can you use a lcd panel as a grow light free sample

One of the biggest expenses in indoor hydroponics is the cost of grow lights. While some high-quality grow lights are on the market, they can be expensive. This blog post will discuss cheap alternatives to high-priced grow lights. We will also provide tips on choosing the best and cheap grow light or artificial light for your needs.

Hydroponics is a soil-less method of growing plants. The plant"s roots are submerged in the water that contains nutrients. Indoor hydroponics is a method of growing plants without soil under controlled conditions. Steps for setting up a grow room or grow tent for indoor hydroponics are similar to those for indoor gardening.

Indoor hydroponic systems use various growing mediums, ranging from simple peat pellets to more complex grow mediums like rockwool and perlite. For example, most plants in a hydroponic garden can be grown in a gravel medium, where the roots are allowed to grow in the spaces between the small stones.

Grow lights are artificial light sources that are used to stimulate plant growth. These lights are essential for indoor gardening, as they provide the plants with the energy they need to photosynthesize.

They are essential because the right kind of light can play a significant role in proper plant growth. For example, some plants will respond better to red light than blue light, while others will thrive with both types of light. In this case, the blue light will help your plants grow better than the red light alone.

Providing the right spectrum of light also means that you"ll be able to grow different types of plants. This means that you"ll have many more options for growing new varieties of vegetables and flowers than you would have otherwise.Light Emitting Diode (LED)

They provide a very specific spectrum of light that plants and flowers use for photosynthesis and plant growth. Without the correct light, your plants will not grow properly and will most likely end up with poor growth.

Grow lights can help you in growing plants more quickly. Plants that grow under grow lights develop quicker than those cultivated in natural light. This is because the grow lights provide optimum radiation for plant development.

Grow lights may also benefit the development of larger plants. Plants that grow under grow lights are typically larger than those cultivated in natural light. This is because grow lights give the best possible illumination level for plant development.

Cheap grow lights come in various shapes and sizes, so choosing the best one for your needs can be challenging. Here are a few tips to help you choose the best cheap grow light:Make sure the grow light is bright enough for your plants. The brightness of a grow light is measured in lumens.

Consider the size of the grow light. If you have a small grow area, choose a small grow light. If you have a large farm area, choose a large grow light.

There are some less expensive or cheap alternatives to grow lights.One option is to use fluorescent light. These are available in various sizes, and they generate very little heat. These bulbs are relatively inexpensive, and they do not generate much heat. However, they are not as bright as some other types of grow lights on the market.

Finally, you can also use sunlight to grow plants indoors. Sunlight is free and provides the correct spectrum of light for plant growth. However, sunlight may not be practical during the winter months, when the days are shorter.

If you want to save money on your grow light setup, you can make your own. Here are a few tips:Use an old coffee can or soup can. Cut holes in the bottom of the can and insert light bulbs.

Hang the can above your plants. To get the best results, you may need to experiment with the grow light height. Read What Is the Ideal Distance for a Grow Light to Be Away from Indoor Plants to learn more.

Grow lights are an important part of indoor hydroponics. They can be expensive, but some cheap lighting alternatives work well. When choosing a grow light, consider the above-given tips. If you"re looking for a more affordable option, making your own grow light is a great way to save money.

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LED Grow Lights are becoming very popular and they are a good choice if you are buying a new grow light system or upgrading your old florescent fixture. This post about LED grow light myths will save you time and money.

As with any new technology there are many myths about LED grow lights. Some are started because of a lack of knowledge by the general public, but many are started by manufacturers who are trying to sell their product. Some of them prefer to keep us in the dark so they can make outrageous claims, but the better companies don’t do this. We need to do our part and become educated consumers so that we can properly evaluate both the message being broadcast and the product itself.

With incandescent and florescent lights, watts were a good measure of the brightness of a light. A 100 watt bulb was always brighter than a 60 watt bulb. Not so with LED. Lower wattage can produce more light.

The watts rating on a LED grow light tells you how much electricity it will use, and therefore the ongoing cost to run the light, but it tells you very little about how bright the light is, or how suitable the light is for growing plants.

How many watts do you need per square foot of growing area? Consumers want to know, and manufacturers are quite willing to give you a rule such as, seedlings need 15 watts per sq foot. You can find similar rules for other types of plants, but none of them mean very much.

As explained above, watts do not equate to the amount of light. But even more important, watts tell you nothing about the quality of light (i.e. the wavelengths of light). What you really want to know is the PPFD (photosynthetic photon flux density) for a given spot under the grow light.

You will have trouble finding a PPFD value for most lights. LED shop lights will not provide this value because they are not being sold specifically for plant growth. Many LED grow lights will not give you this value because they want to sell you on watts and give you that value instead – don’t buy from these companies.

The other reason you will have trouble finding a PPFD value is that many people equate PPFD to PAR. They provide PPFD values but call them PAR values. They just don’t understand what PAR means – it is a measure of light quality, not intensity.

If the product does not advertise a PPFD value, but does show you a PAR value – you can usually assume they are the same thing. The units should be μmol/m2/s.

The term PAR (Photosynthetically Active Radiation), when properly used, describes the light spectra that plants use, between 400 and 700 nm. Since plants use more blue and red light these colors get weighted higher than yellow and green.

A common misconception of LED lights is that they are 100% efficient at turning electricity into light. Granted they are more efficient than older technology like incandescent and florescent lights, but they are not 100% efficient.

In theory LED lights could convert all of the electricity into light, but that only works in story books. In real life, an LED converts 20% or more of the electricity into heat.

A light fixture containing 100 individual LED bulbs creates a lot of heat. The lights are designed so that most of this heat comes out the back of the fixture, directing it away from the plant. Larger units also contain fans that blow the heat away. This is important since heat shortens the life of LED bulbs.

LED bulbs – the single units that give off the light, are available in various watt ratings. 1, 3, 5, 10 watt bulbs are common. This leads to another myth. It is common to see the claim that a 3 watt unit does not produce as much light as a 5 watt unit – so the 5 must be better. It is not that simple.

Most bulbs are not run at 100% efficiency. Higher wattage bulbs tend to be run at lower efficiency levels since they produce too much heat at higher efficiency. So a 5 watt bulb may be giving the same amount of light as a 3 watt bulb.

Higher watt bulbs are newer technology and generally cost more. They may also have a shorter life. Given the current technology, your best bang for the buck is a 3 watt bulb. It is a good compromise between efficiency, reliability and cost.

A newer technology called COB LED (chip-on-board LED), is more efficient, has a longer life, but is more expensive. At the moment, I think the technology is too new and still has issues. One potential benefit of this technology is that it allows the manufacture to make longer light tracks, similar to a traditional 4 ft florescent fixture. In that configuration it would cover a larger area for home use.  Manufacturers have not taken advantage of this feature, maybe because of higher shipping costs for a larger unit, but there are some DIY systems worth looking into, such as the one pictured here, created by Ichabod Crane on International Canagraphic Magazine.

Plants have evolved under the sun, so we assume sunlight is what plants want. It is not. Much of the yellow and green light in sunlight is not used by plants.

Traditionally we have always grown plants under white light, and outside they grow under sunlight which is a yellow-white. It is natural to think white light is better for growing plants – its not.

The best light is one that produces the wavelengths of light that plants need in the relative amounts plants want. They use more blue and red, and less yellow and green. It does not have to look white.

As light moves away from the source, the light spreads out, and the intensity at any given point is reduced. This follows theinverse square rule, whereby if the distance doubles, the intensity is reduced to 1/4. If you move a plant from 1 ft under the light to 2 ft, it will receive 1/4 as much light.

This rule works for point sources of light, but most LED fixtures contain many LED bulbs, so they are not a point source of light. Therefore the rule does not apply to LED lights.

The other complication is that in the real world the rule only works well right below the light source. As you move out to the sides, the rule is also not valid.

Since it is important to know how much light you get at any point under the fixture, the manufacturer should provide you with that information, as seen in the diagram below

What is the growing area under an LED light? This is an important question since it determines how many plants you can grow and it varies from lamp to lamp.

Manufacturers try to help you by providing a “coverage area value” and say something like, the coverage area is 8 sq feet. That sounds great, but this number means absolutely nothing. If you raise a light up higher it will cover more area, so unless they also provide the height of the light and the light intensity values across that whole area, the coverage area number is of no value.

Lets have a close look at this. The diagram below shows the coverage area for a Viparspectra Par 700 light. You are viewing the growing area from above the light and the numbers are the PPFD values at certain points under the light, with the light hanging at 2 feet above the growing surface.

The specifications for this light suggest a coverage area of “Core Coverage at 24″ Height is 4x3ft“. The reason why this area is longer than wide is because the shape of the light is a rectangle. It makes no sense that the above diagram shows circles and squares for a rectangular light, but lets assume the numbers are correct.

Directly under the light you have a PPFD value of 780, which is lots of light to grow and flower any plant. Assume you want to cover a 3 x 3 ft area, the light at the edges of this growing area have a PPFD of between 30 and 200. That is enough for growing seedlings, but not much more.

Lets look at this from a different perspective. Lets say that after doing a lot of diligent research you decide that you want to provide a minimum PPFD of 300. That reduces the growing area under this light to a 2 x2 ft area, and even then the corners will only be getting about 200 PPFD. So for your requirements (ie 300 PPFD), your coverage area is 2 x 2 ft, not the advertised 4 x 3 ft.

Without seeing this light distribution diagram and knowing the height used to measure the values, the coverage area in the specifications is of little help. At least Viparspectra provides this information; many manufacturers don’t. If they don’t, don’t buy from them.

This one is not really a myth, but it does confuse things. PAR 20 and PAR 30 are lamp size designations and PAR in this case stands for parabolic aluminized reflector. It describes the shape and size of the bulb and has nothing to do with the quality of the light. PAR 20 and PAR 30 are common sizes for bulbs used in the home.

A bit of factual information can easily lead to incorrect conclusions. Plants look green because they reflect green light and absorb red an blue. That makes sense and it follows that if they reflect green light, they don’t use it.

The absorption spectra for extracted chlorophyll shows peaks in the blue and red zones, but no absorption of green light. Again we conclude plants don’t use green light in photosynthesis.

We are wrong. Some green light (around 500 nm) is absorbed by plants, and when we look at photosynthesis in a whole leaf instead of extracted chlorophyll, it is clear that green light does contribute to photosynthesis.

We now know that plants grow best with a wide spectrum that contains all wavelengths including near IR and maybe even near UV. A good LED grow light will provide a wide spectrum which includes some green light.

LED lights tend to produce less heat than older technology, and their light intensity is relatively low. This has lead to the conclusion that you can put plants as close to the lights as you want and you won’t burn them.

The reality is that modern LED grow lights can produce a very high level of light and it can cause photo-bleaching and burn leaves. This depends very much on the plant, but a PPFD of 800 is enough to damage some plants.

This was a myth even with florescent technology but it persists with LED. People using cool white (more blue light) bulbs used to add a few incandescent bulbs (very red light) when it was time for plants to flower. It was believed that red light was needed to initiate the flowering process.

Some of the early LED lights were red and blue and it naturally followed that the blue ones would be best for veg and the red for flowers. There are even lights that allow you to switch between a veg mode ( more blue bulbs on) and a flower mode (more red bulbs on).

The reality is that plants grow and flower best with both blue and red light all of the time. For production you might want to fine tune this at different stages in a growth cycle, but for home use we can ignore it.

Lumens is a measure of light intensity so it logical to think that a grow light with more lumens is better. The problem is that lumens measure intensity based on the human eye, and we see green and yellow light much better than red and blue.

Consider this extreme case where the light is only yellow. People see a lot of light and therefore it gets a high lumen rating. But plants don’t use yellow light very well, so for a plant this light has a very low intensity.

Some of the early LED shop lights did not produce much light and were not suitable for growing plants, except for some very low light level requirements. That has all changed. The newer LED shop lights provide lots of light for seedlings and low level plants like lettuce and African violets.

You can buy complete systems including the reflectors or you can buy 4 ft long LED tubes that replace traditional florescent bulbs, allowing you to continue using the existing fixtures. Even better is that the price of these has come way down.

Florescent tubes and the new LED shop lights measure the color of light using a Kelvin (K) scale. A blue-white has a higher Kelvin value than a red-white. Since Kelvin is a unit of measure for temperature these lights are also called cool and warm.

Light in spring is more blue, and fall light is more red. Some people believe that it is a good idea to mimic this natural shift by using bluer light (6500 Kelvin) in spring and a redder light (3500 Kelvin) in fall.

In northern and southern hemispheres there is a real shift in color because sun light has to travel through more atmosphere in winter, but the change from spring to fall is only 300-500K. That is not significant enough to warrant changing lights with the seasons.

In the world of LED grow lights, Kelvin means very little. It is much better to compare actual spectra, but they can be hard to come by. Some manufacturer do show them on their website.

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A grow light is an electric light to help plants grow. Grow lights either attempt to provide a light spectrum similar to that of the sun, or to provide a spectrum that is more tailored to the needs of the plants being cultivated (typically a varying combination of red and blue light, which generally appears pink to purple to the human eye). Outdoor conditions are mimicked with varying colour temperatures and spectral outputs from the grow light, as well as varying the intensity of the lamps. Depending on the type of plant being cultivated, the stage of cultivation (e.g. the germination/vegetative phase or the flowering/fruiting phase), and the photoperiod required by the plants, specific ranges of spectrum, luminous efficacy and color temperature are desirable for use with specific plants and time periods.

Grow lights are used for horticulture, indoor gardening, plant propagation and food production, including indoor hydroponics and aquatic plants. Although most grow lights are used on an industrial level, they can also be used in households.

According to the inverse-square law, the intensity of light radiating from a point source (in this case a bulb) that reaches a surface is inversely proportional to the square of the surface"s distance from the source (if an object is twice as far away, it receives only a quarter the light) which is a serious hurdle for indoor growers, and many techniques are employed to use light as efficiently as possible. Reflectors are thus often used in the lights to maximize light efficiency. Plants or lights are moved as close together as possible so that they receive equal lighting and that all light coming from the lights falls on the plants rather than on the surrounding area.

Example of an HPS grow light set up in a grow tent. The setup includes a carbon filter to remove odors, and ducting to exhaust hot air using a powerful exhaust fan.

A range of bulb types can be used as grow lights, such as incandescents, fluorescent lights, high-intensity discharge lamps (HID), and light-emitting diodes (LED). Today, the most widely used lights for professional use are HIDs and fluorescents. Indoor flower and vegetable growers typically use high-pressure sodium (HPS/SON) and metal halide (MH) HID lights, but fluorescents and LEDs are replacing metal halides due to their efficiency and economy.

High-pressure sodium lights are also used as a single source of light throughout the vegetative and reproductive stages. As well, they may be used as an amendment to full-spectrum lighting during the reproductive stage. Red spectrum light may trigger a greater flowering response in plants.

In recent years LED technology has been introduced into the grow light market. By designing an indoor grow light using diodes, specific wavelengths of light can be produced. NASA has tested LED grow lights for their high efficiency in growing food in space for extraterrestrial colonization. Findings showed that plants are affected by light in the red, green and blue parts of the visible light spectrum.

LED grow lights are usually composed of multiple individual light-emitting diodes in a casing with a heat sink and built-in fans. Most or all LEDs use AC/DC or DC/DC power supplies that provide constant direct current through the LEDs, regulating the amount of total power the LEDs can draw and preventing their failure.

Individual LEDs usually provide only a single narrow range of colors, and so different color LEDs are mixed in grow lights in proportions depending on the intended use. It is known from the study of photomorphogenesis that green, red, far-red and blue light spectra have an effect on root formation, plant growth, and flowering, but there are not enough scientific studies or field-tested trials using LED grow lights to recommend specific color ratios for optimal plant growth under LED grow lights.

White LED grow lights provide a full spectrum of light designed to mimic natural light, providing plants a spectrum of red, blue and green. White light is rated on a spectrum in terms of Color temperature where cooler lights produce more blue photons and warmer lights produce more red photons.

A large number of plant species have been assessed in greenhouse trials to make sure plants have higher quality in biomass and biochemical ingredients even higher or comparable with field conditions. Plant performance of mint, basil, lentil, lettuce, cabbage, parsley, carrot were measured by assessing health and vigor of plants and success in promoting growth. Promoting in profuse flowering of select ornamentals including primula, marigold, stock were also noticed.

In tests conducted by Philips Lighting on to find an optimal light recipe for growing various vegetables in greenhouses, they found that the following aspects of light affects both plant growth (photosynthesis) and plant development (morphology): light intensity, total light over time, light at which moment of the day, light/dark period per day, light quality (spectrum), light direction and light distribution over the plants. However it"s noted that in tests between tomatoes, mini cucumbers and bell peppers, the optimal light recipe was not the same for all plants, and varied depending on both the crop and the region, so currently they must optimize LED lighting in greenhouses based on trial and error. They"ve shown that LED light affects disease resistance, taste and nutritional levels, but as of 2014 they haven"t found a practical way to use that information.

The diodes used in initial LED grow light designs were usually 1/3 watt to 1 watt in power. However, higher wattage diodes such as 3 watt and 5 watt diodes are now commonly used in LED grow lights. For highly compacted areas, COB chips between 10 watts and 100 watts can be used. Because of heat dissipation, these chips are often less efficient. Standard LED lighting usually has a power factor of at least 0.90, while good quality LED lights will be around 0.99.

To prevent leaf burn, LED grow lights should be kept between 12 inches (30 cm) away from plants for lower wattage lamps (under 300 watts) up to 36 inches (91 cm) away from plants for higher wattage lamps (1000 watts or more).

Historically, LED lighting was very expensive, but costs have greatly reduced over time, and their longevity has made them more popular. LED grow lights are often priced higher, watt-for-watt, than other LED lighting, due to design features that help them to be more energy efficient and last longer. In particular, because LED grow lights are relatively high power, LED grow lights are often equipped with cooling systems, as low temperature improves both the brightness and longevity. LEDs usually last for 10,000 - 50,000 hours until LM-70 is reached.

All HID grow lights require an electrical ballast to operate, and each ballast has a particular power rating. Popular HID ratings include 150W, 250W, 400W, 600W and 1000W. 600W HID lights are the most electrically efficient as far as light produced, followed by 1000W. A 600W HPS produces 7% more light (lumen-per-watt) than a 1000W HPS.

Although all HID lamps work on the same principle, the different types of bulbs have different starting and voltage requirements, as well as different operating characteristics and physical shape. Because of this a bulb won"t work properly without a matching ballast, even if the bulb will physically screw in. In addition to producing lower levels of light, mismatched bulbs and ballasts will stop working early, or may even burn out immediately.

Metal halide bulbs are a type of HID light that emit light in the blue and violet parts of the light spectrum, which is similar to the light that is available outdoors during spring.

Metal halide lamps are widely used in the horticultural industry and are well-suited to supporting plants in earlier developmental stages by promoting stronger roots, better resistance against disease and more compact growth.

They are now being made for digital ballasts in a pulse start version, which have higher electrical efficiency (up to 110 lumens per watt) and faster warmup.

Ceramic metal halide (CMH) lamps are a relatively new type of HID lighting, and the technology is referred to by a few names when it comes to grow lights, including ceramic discharge metal halide (CDM),ceramic arc metal halide.

Ceramic metal halide lights are started with a pulse-starter, just like other "pulse-start" metal halides.polycrystalline alumina (PCA), which is similar to the material used for an HPS. PCA reduces sodium loss, which in turn reduces color shift and variation compared to standard MH bulbs.

Combination HPS/MH lights combine a metal halide and a high-pressure sodium in the same bulb, providing both red and blue spectrums in a single HID lamp. The combination of blue metal halide light and red high-pressure sodium light is an attempt to provide a very wide spectrum within a single lamp. This allows for a single bulb solution throughout the entire life cycle of the plant, from vegetative growth through flowering. There are potential tradeoffs for the convenience of a single bulb in terms of yield. There are however some qualitative benefits that come for the wider light spectrum.

An HPS (High Pressure Sodium) grow light bulb in an air-cooled reflector with hammer finish. The yellowish light is the signature color produced by an HPS.

High-pressure sodium lights are a more efficient type of HID lighting than metal halides. HPS bulbs emit light in the yellow/red visible light as well as small portions of all other visible light. Since HPS grow lights deliver more energy in the red part of the light spectrum, they may promote blooming and fruiting.

Plants grown under HPS lights tend to elongate from the lack of blue/ultraviolet radiation. Modern horticultural HPS lamps have a much better adjusted spectrum for plant growth. The majority of HPS lamps while providing good growth, offer poor color rendering index (CRI) rendering. As a result, the yellowish light of an HPS can make monitoring plant health indoors more difficult. CRI isn"t an issue when HPS lamps are used as supplemental lighting in greenhouses which make use of natural daylight (which offsets the yellow light of the HPS).

High-pressure sodium lights have a long usable bulb life, and six times more light output per watt of energy consumed than a standard incandescent grow light. Due to their high efficiency and the fact that plants grown in greenhouses get all the blue light they need naturally, these lights are the preferred supplemental greenhouse lights. But, in the higher latitudes, there are periods of the year where sunlight is scarce, and additional sources of light are indicated for proper growth. HPS lights may cause distinctive infrared and optical signatures, which can attract insects or other species of pests; these may in turn threaten the plants being grown. High-pressure sodium lights emit a lot of heat, which can cause leggier growth, although this can be controlled by using special air-cooled bulb reflectors or enclosures.

Conversion bulbs are manufactured so they work with either a MH or HPS ballast. A grower can run an HPS conversion bulb on a MH ballast, or a MH conversion bulb on a HPS ballast. The difference between the ballasts is an HPS ballast has an igniter which ignites the sodium in an HPS bulb, while a MH ballast does not. Because of this, all electrical ballasts can fire MH bulbs, but only a Switchable or HPS ballast can fire an HPS bulb without a conversion bulb.

A switchable ballast is an HID ballast can be used with either a metal halide or an HPS bulb of equivalent wattage. So a 600W Switchable ballast would work with either a 600W MH or HPS.

Fluorescent lights come in many form factors, including long, thin bulbs as well as smaller spiral shaped bulbs (compact fluorescent lights). Fluorescent lights are available in color temperatures ranging from 2700 K to 10,000 K. The luminous efficacy ranges from 30 lm/W to 90 lm/W. The two main types of fluorescent lights used for growing plants are the tube-style lights and compact fluorescent lights.

Fluorescent grow lights are not as intense as HID lights and are usually used for growing vegetables and herbs indoors, or for starting seedlings to get a jump start on spring plantings. A ballast is needed to run these types of fluorescent lights.

Standard fluorescent lighting comes in multiple form factors, including the T5, T8 and T12. The brightest version is the T5. The T8 and T12 are less powerful and are more suited to plants with lower light needs. High-output fluorescent lights produce twice as much light as standard fluorescent lights. A high-output fluorescent fixture has a very thin profile, making it useful in vertically limited areas.

Fluorescents have an average usable life span of up to 20,000 hours. A fluorescent grow light produces 33-100 lumens/watt, depending on the form factor and wattage.

Compact Fluorescent lights (CFLs) are smaller versions of fluorescent lights that were originally designed as pre-heat lamps, but are now available in rapid-start form. CFLs have largely replaced incandescent light bulbs in households because they last longer and are much more electrically efficient.

While standard CFLs in small sizes can be used to grow plants, there are also now CFL lamps made specifically for growing plants. Often these larger compact fluorescent bulbs are sold with specially designed reflectors that direct light to plants, much like HID lights. Common CFL grow lamp sizes include 125W, 200W, 250W and 300W.

Compact fluorescent bulbs are available in warm/red (2700 K), full spectrum or daylight (5000 K) and cool/blue (6500 K) versions. Warm red spectrum is recommended for flowering, and cool blue spectrum is recommended for vegetative growth.

A cold cathode is a cathode that is not electrically heated by a filament. A cathode may be considered "cold" if it emits more electrons than can be supplied by thermionic emission alone. It is used in gas-discharge lamps, such as neon lamps, discharge tubes, and some types of vacuum tube. The other type of cathode is a hot cathode, which is heated by electric current passing through a filament. A cold cathode does not necessarily operate at a low temperature: it is often heated to its operating temperature by other methods, such as the current passing from the cathode into the gas.

The quantity, quality, and duration of light regulate plant growth and development. In general, if a plant does not get enough light, it will become stunted, have reduced pigmentation, or begin shade-avoidance response. A plant that does not receive the right quality of light may exhibit physiological differences when compared to the same plants grown under optimal lighting conditions.

Grow light quantity and quality has been technologically limited in the past. High pressure sodium (HPS) and metal halide (MH) were and are still common supplemental lighting options for greenhouses and some sole-source operations.LED grow lights composed solely of blue and red LEDs due to both their efficiency at converting electricity to photons and efficiency at driving photosynthesis. As LEDs become less expensive and more efficient, an interest in studying light quality has risen in the field of plant science.

Light quantity refers to the amount of light a plant requires each day for optimal growth. Historically, light quantity was expressed in units of W m−2, lumens, or lux. While these units are useful in energy calculations, W m−2, or in human lighting (lumens and lux), plant scientists now prefer to measure the photosynthetic photon flux density (PPFD), in units of μmol m−2s−1. PPFD is an explicit measure of the quantity of photons hitting a surface per square meter per second, a more accurate way to measure how plants interact with photons.

Another useful way to measure light quantity is through the daily light integral, or DLI. The DLI takes into account the PPFD and the total number of hours a plant is exposed to that PPFD to get the total quantity of photons per day, in units of mol m−2d−1. The equation for converting PPFD to DLI, assuming constant PPFD, is below.DLI (mol m−2d−1) =0.0036 * PPFD (μmol m−2s−1) *Hours of Light

The light quantity requirements for crops vary, in general the light requirement for a specific crop is greater for crops that are fruiting and flowering and is less for crops that remain vegetative. Leafy greens such as lettuce, spinach, and kale are typically considered low-light crops, requiring a DLI between 12 and 17 mol m−2d−1. Tomatoes, cucumbers, and peppers require between 20-30 mol m−2d−1. Cannabis has one of the highest light requirements of cultivated plants, requiring a DLI of up to 40 mol m−2d−1.

Absorbance spectra of free chlorophyll a (blue) and b (red) in a solvent. The action spectra of chlorophyll molecules are slightly modified in vivo depending on specific pigment-protein interactions.

Light quality refers to the spectral distribution of light given to a plant. Light quality is grouped into colors based on wavelength; 320-400 nanometers (nm) is UVA, 400-500 nm is blue, 500-600 nm is green, 600-700 nm is red, and 700-750 nm is far red, sometimes referred to as near-infrared. Light quality can also be expressed as ratios, e.g. 3:2 red:blue ratio, or sometimes as their peak irradiance, e.g. 450 nm blue light and 660 nm red light.

Photomorphogenesis is the term for light-mediated plant responses to light spectrum. Plants are able to sense parts of the electromagnetic spectrum through a network of photoreceptors including phytochromes, cryptochromes, phototropin, and zeiltupe. Each receptor is able to sense different parts of the electromagnetic spectrum. Information about the light spectrum can affect seed germination, the signal to transition from vegetative to flowering, and the production of secondary metabolites such as anthocyanins.

In addition, many plants also require both dark and light periods, an effect known as photoperiodism, to trigger flowering. Therefore, lights may be turned on or off at set times. The optimum photo/dark period ratio depends on the species and variety of plant, as some prefer long days and short nights and others prefer the opposite or intermediate "day lengths".

Much emphasis is placed on photoperiod when discussing plant development. However, it is the number of hours of darkness that affects a plant’s response to day length.

Plants that flower in response to photoperiod may have a facultative or obligate response. A facultative response means that a plant will eventually flower regardless of photoperiod, but will flower faster if grown under a particular photoperiod. An obligate response means that the plant will only flower if grown under a certain photoperiod.

Weighting factor for photosynthesis. The photon-weighted curve is for converting PPFD to YPF; the energy-weighted curve is for weighting PAR expressed in watts or joules.

Lux and lumens are commonly used to measure light levels, but they are photometric units which measure the intensity of light as perceived by the human eye.

The spectral levels of light that can be used by plants for photosynthesis is similar to, but not the same as, what is measured by lumens. Therefore, when it comes to measuring the amount of light available to plants for photosynthesis, biologists often measure the amount of photosynthetically active radiation (PAR) received by a plant.nanometers, which generally corresponds to the spectral range that photosynthetic organisms are able to use in the process of photosynthesis.

The irradiance of PAR can be expressed in units of energy flux (W/m2), which is relevant in energy-balance considerations for photosynthetic organisms. However, photosynthesis is a quantum process and the chemical reactions of photosynthesis are more dependent on the number of photons than the amount of energy contained in the photons.−2s−1, but the value relevant for plant growth is the Daily light integral (DLI), the PPFD integrated over 24 hours. Most plant species will grow well with a DLI of 5-15 mol m−2 day−1. Shade-tolerant species can grow with DLI values of 1-3 mol m−2 day−1, light-demanding species easily handle 30-50 mol m−2 day−1.

"How to Choose the Proper Grow Light for Your Indoor Garden". primalgrowgear.com. 2021-08-27. Archived from the original on 2022-01-05. Retrieved 2022-01-05.

Goins, G. D.; Yorio, N. C.; Sanwo-Lewandowski, M. M.; Brown, C. S. (1998-01-01). "Life cycle experiments with Arabidopsis grown under red light-emitting diodes (LEDs)". Life Support & Biosphere Science: International Journal of Earth Space. 5 (2): 143–149. ISSN 1069-9422. PMID 11541670.

Massa, Gioia D.; Kim, Hyeon-Hye; Wheeler, Raymond M.; Mitchell, Cary A. (2008-12-01). "Plant Productivity in Response to LED Lighting". HortScience. 43 (7): 1951–1956. doi:ISSN 0018-5345.

Kim, Hyeon-Hye; Wheeler, Raymond M.; Sager, John C.; Yorio, Neil C.; Goins, Gregory D. (2005-01-01). "Light-emitting diodes as an illumination source for plants: a review of research at Kennedy Space Center". Habitation. 10 (2): 71–78. doi:10.3727/154296605774791232. ISSN 1542-9660. PMID 15751143.

Sabzalian, Mohammad R., Parisa Heydarizadeh, Morteza Zahedi, Amin Boroomand, Mehran Agharokh, Mohammad R. Sahba, and Benoît Schoefs. "High performance of vegetables, flowers, and medicinal plants in a red-blue LED incubator for indoor plant production." Agronomy for Sustainable Development 34, no. 4 (2014): 879-886.

Abhay Thosar, Ph.D., Esther Hogeveen van Echtelt (July 29, 2014). LED: the New Fast-track to Growth: Recipe Development and Practical Applications in Horticulture - Part 1: Global Examples LED Recipes and Development (Video). Orlando, FL. Event occurs at 00:03:15, 00:13:05. Archived from the original on February 16, 2016. Retrieved February 12, 2015.

Zelenskii, M. I. (1987). "Photosynthetical Activity of Spring Wheat in Light Defficient [sic] Conditions" (PDF). Proceedings of the Indian National Science Academy, Section B. 53 (5–6): 401–406.

Aphalo, P. J.; Ballare, C. L.; Scopel, A. L. (1999-11-01). "Plant-plant signalling, the shade-avoidance response and competition". Journal of Experimental Botany. 50 (340): 1629–1634. doi:ISSN 0022-0957.

McCree, K. (1972a). "The action spectrum, absorptance and quantum yield of photosynthesis in crop plants". Agric. Meteorol. 9: 191–216. doi:10.1016/0002-1571(71)90022-7.

Potter, David J.; Duncombe, Paul (May 2012). "The Effect of Electrical Lighting Power and Irradiance on Indoor-Grown Cannabis Potency and Yield: EFFECTS OF LIGHTING POWER ON CANNABIS". Journal of Forensic Sciences. 57 (3): 618–622. doi:10.1111/j.1556-4029.2011.02024.x. PMID 22211717. S2CID 20822748.

Poorter, Hendrik; Niinemets, Ülo; Ntagkas, Nikolaos; Siebenkäs, Alrun; Mäenpää, Maarit; Matsubara, Shizue; Pons, ThijsL. (8 April 2019). "A meta‐analysis of plant responses to light intensity for 70 traits ranging from molecules to whole plant performance". New Phytologist. 223 (3): 1073–1105. doi:PMID 30802971.

You’ve done your research on color spectrum for plant cultivation. You know blue light is essential for growth and development. You know red light promotes flowering. You know LED grow lights are most efficient. Now as you look at your options, you wonder: “Can I just use blue and red LED lights? Do I need all this extra research.”

The short answer: No, you can’t, and yes, you do. While the color spectrum is essential for expert cultivation, it is not the only factor that can make or break your operation. Here’s a quick guide for choosing the right blue and red lights so you can narrow down the possibilities.

In order to thrive, your plants need plenty of photons that fall within the PAR range. PAR refers to “photosynthetically active radiation.” In short, these are the wavelengths your plants actually use for photosynthesis.

As you know, blue light is a major player in the vegetative phase. Blue promotes root development and strong, stocky plant growth. When you blast your young plants with blue, you prepare them to sustain a ton of buds in the future.

It follows, then, that you do need light sources can provide both the red and blue light spectrum. But red and blue are only the beginning. There are a few more considerations that help youchoose the right lights.

It isn’t enough to give your plants light within the PAR range. They need to get enough of that light to thrive. This is why you can’t just screw in a blue incandescent light bulb and call it a grow room.

Look at this way. In nature, plants get all their light from the sun. That is some high intensity light. If you plan to in a grow room or agrow tent, you have to provide the light spectrum your plants would get from the sunanddeliver enough photons to support photosynthesis.

In the language of indoor cultivation,what you’re looking for is PPFD. PPFD stands for “photosynthetic photon flux density.” This measurement tells you the amount of usable light (PAR) that actually reaches your crop when you use a given grow light.

If you’re growing a flowering plant, you need around 300 – 600 umols for the vegetative phase and 800 – 1,000 umols for flowering. That’s a high PPFD, and it narrows your options for grow lights considerably. The two likeliest places to find the spectrum and intensity you need are:

HID (high-intensity discharge) lamps used to be the preferred option for indoor growing. The greatest benefit of these bulbs is right there in the name: high intensity.

However, HID bulbs are not full-spectrum lights. In order to accommodate the needs of their plants, HID growers have to switch between two different bulbs. During vegetation, they use MH (metal halide) lights, which radiate light in the blue spectrum. For the flowering phase, they switch out MH bulbs for HPS, which favors red light.

For years, this method has been the most effective way to promote healthy plants and substantial yields. But now, the landscape of grow light technology is changing. Blue and red LED lights arefast becoming the number one choice over MH and HPS bulbs.

LED grow lights easily match the intensity of HID bulbs. They radiate that essential blue and red light. And high quality LED grow lights accomplish this while also:

Now, this all explains why LED grow lights are easier to use and more cost-effective in the long run. But it’s also worth considering how the highest quality LED grow lights set new standards for the ideal color spectrum.

Blue and red light are so essential that they’re almost all you hear about when you’re new to cultivation. The problem is that these are not theonlycolors your plants use within the PAR range.

While your plants get the most use out of red and blue, colors in the middle of the PAR range also serve a purpose. Green light, for example, penetrates the canopy better than the rest of the color spectrum.

The best LED grow lights provide the exact spectrum your plants require . . . and only that spectrum. This ensures your crop gets everything it needs and no light goes to waste.

One great example of afull spectrum LED grow lightis theSolarXtreme seriesby California Lightworks. Every lamp in this collection includes the exclusive Optigrow spectrum, tailored specifically to the needs of your plants.

Serious growers may even want to kick their game up a notch withvariable spectrum LED lights, like theSolarSystem series. A variable spectrum LED allows you to adjust color levels.

There are countless benefits to having that kind of control. By manipulating the spectrum, you can usher your indoor plants through the grow cycle at a faster rate. You can make nuanced adjustments to your light recipes in real time, depending on how your plant responds.

You also don’t have to choose between strictly blue or red LED lights. Instead, you can create a more natural ratio of red to blue LED light, promotinghigher yieldsanda more flavorful harvest.

It’s easier than ever to find low-cost blue and red LED lights on Amazon or Ebay. The problem is that these lamps are not coming from a reliable manufacturer who understands the science of indoor grows.

Rather, these arecheap LEDs made in China. They produce a vastly inferior light quality, they break in a matter of weeks, and they may not even be safe.

There is also absolutely no chance that these budget manufacturers could even begin to answer your questions. It may cost more in the immediate future to choose a reputable LED brand, but you’ll get both the quality and customer service you need to support a healthy crop.

Even once you’ve decided to bank on the benefits of full-spectrum LED lights, you still face the challenge ofchoosing the best LED grow lightfor your setup.

We recommend starting with either theSolarXtreme seriesorSolarSystem seriesby California Lightworks. The SolarXtreme series provides full-spectrum lamps that are both high powered and hobbyist-friendly. The SolarSystem series is also easy to use, but the technology is more sophisticated and provides variable spectrum control.

If you need any help navigating these options,please let us know. We understand how daunting the light selection process can be, and we’re happy to help growers however we can.

These types of lights "produce light by passing an electric current between two tungsten electrodes inside a glass tube containing gases and metal salts".

Sometimes grow lights will come with all the accessories needed but many times you must buy the accessories separately. Here are some highly rated and reviewed grow light accessories:

When space is efficiently used with grow lights, vertical farming stacks can also be feasible by creating multiple layers of plant beds and grow lights.

To get an approximate idea of the space you will need vertically, see the tables below for LED (light emitting diode) and HPS (high pressure sodium) lighting.

Heat From Fluorescent Grow Lights:CFL, T5, and T8 will typically have modest power draws and efficiency. Will generate more heat than an LED but less than HID lights.

Will generate significant heat, may need to use with fans or other tools for ventilation. To get the power benefits of HID lights while reducing the heat creation, ceramic metal halide (CMH) grow lights offer less heat output but are more expensive than HPS or MH.

In recent years, BTU calculators (example above) have been popular tools used to make sure that the heat generated by your grow light does not cause your room to overheat.

With LED grow lights, heat generated will be less significant, however for HID grow lights, here are example values for BTUs generated for different strengths of grow light:

BTU Calculations are meant to be general guides. Factors such as insulation, ambient temperature outside, and ceiling height can affect the thermodynamics of any given indoor growing space.

Therefore, when evaluating an LED grow-light (or any grow light) for use, (as far as color spectrum goes) you should look for a grow light which offers:

Lumens are defined as,  "a unit of measure describing the total quantity of light from the visible spectrum that is emitted from a source of light (in all directions)".

Keep in mind however, that lux is a measure of light visible to humans, NOT plants. In order to get a better concept of light visible to plants, you must use PAR measurement instead of lux.

PAR photon irradiance (often abbreviated as just PAR) is a metric which gives allows the best understanding of the light which your plants are getting from your grow light.

Watts are important because grow light manufacturers will commonly display Wattage in their product specs as a proxy for the power capability of the light.

‍A last important spec to consider is rated life of your lighting and how that coincides with not only your budget but your "day-length", or how long you are using your grow lights on a day to day basis.

While some types of grow lights have rated lifetimes of over 10 years, warranties on lights often will fall into the 3-5 year range. The durability of your light will be determined primarily by how you use it.

‍A last important spec to consider is rated life of your lighting and how that coincides with not only your budget but your "day-length", or how long you are using your grow lights on a day to day basis.

While some types of grow lights have rated lifetimes of over 10 years, warranties on lights often will fall into the 3-5 year range. The durability of your light will be determined primarily by how you use it.

$$: T5, T8, T12 fluorescent: good value for less than 100 USD. A 4 tube T5 grow light system can generate multiple hundreds of dollars worth of produce in a year (1-2 year pay back period with all other costs factored in besides lighting).

$$$: LED and High Pressure Sodium (small sizes): most LED solutions will be on the pricier side relative to fluorescent, if you are going to spend on LED"s, your best option is to invest in a light from a well established LED vendor (full explanation in the next section "Vendor Quality")

$$$$: Most heavy duty commercial style systems will involve high pressure sodium/metal halide (collectively referred to as HID or high intensity discharge)and high priced options are increasingly now appearing for LED systems. These systems will range in the thousands of dollars+ (USD) and will often be part of larger systems involving grow tents, grow "boxes", air filters, fans, controlled environment features, etc.

For grow lights, ratings and reviews on sites like Amazon, Alibaba, or even niche sites for grow lights may not guarantee you are receiving the product quality you paid for.

In this case study from Albopepper.com the true wattage of brand new LED grow lights varied wildly (one light had 34.2% lower wattage than advertised).

When you are paying for grow lights, a lot of what you are paying for is wattage, so this is a serious risk to consider when buying grow lights. This sort of issue could cost you hundreds if not thousands of dollars, and, most importantly, time, if undetected.

Solution: trusted brands like Lumigrow may have more expensive products but also have a long track record of shipping consistently performing products. International products from countries like China should be reviewed thoroughly.

If you are looking for a grow lights kit a simple search online will help you several options. We recommend looking on Amazon, Home Depot, eBay, Gardeners Supply, or other well-known vendors to get an idea of the options available.

Often times a grow light will be the only part of the "package" or "kit" you are purchasing. Here are other potential additions besides the grow light that you should know about:

Ballast/fixture: grow light systems require an electrical component called a ballast to regulate the power supply in the grow light. if you are buying just a bulb, of course you will also need a ballast. this is a necessary component for lights. ballasts can be purchased independently from grow lights but grow lights can also have the ballasts incorporated into unit.

Grow Tents: grow tents are another feature mainly seen with more expensive systems. Tip: It"s worth noting that many of the benefits of a grow tent that help create a more controlled growing environment can be replicated cheaply DIY (not all the benefits).

Now, whether you are just getting started with a grow kit or building an entire grow room, you will need to understand the unit economics of what you are doing.

1) Know the rate paid for electricity: this will typically be expressed in cents / kWhr (kilowatt hr). Your kWhr price can be provided by your electricity provider. Keep in mind that the full cost of your electricity is not just the kWhr cost.

2) Know the wattage of your bulbs. Given the kWhr prices above, if you are using 2 40w fluorescent bulbs, then your total wattage is 80 w (40 * 2). To find the cost of operation, divide 80/1000 (1000 because the unit is kilowatt hrs), then multiply by $0.12/kWr.

2. HID is currently still the best at scale for most commercial applications, although with the rapid advance of LED"s grow light technology the advantages over LEDs at scale are less and less significant.

3. LED is the grow light technology that has gained the most ground in the past decade. It offers many scalability advantages that neither CFL or HID offer.

Verdict: If you are interested in scalability and are willing to invest capital in the long term growth of your grow light system, upper end LED"s will once again be the best way to go.

1) For household growing projects where pets or children may be disturbing the lights, LEDs are much less likely to break when knocked down or jostled, due to the small size of the diodes and the way they are situated in the fixture.

Other lighting systems like fluorescent tubes and HPS lighting can be very fragile and will shatter or even explode if they are knocked over with enough force.

2a: Fire - it is a common misconception that fires started by grow lights are caused simply by heat creation. Many fires casued by grow lights are electrical fires that result from incorrect electrical sources not designed for grow lights.

Large grow light fixtures typically require 220 V "dryer" outlets. Overloading your electrical outlet combined with long periods of running time can pose a risk for indoor growers.

When grow lights cycle on and off, the moisture level in the growing spaces changes. This continuous changing of moisture (lights on = low moisture, lights off = condensing of moisture), can increase the risk of mold or mildew which can be harmful to humans.

Many types of grow lights, with one exception being LEDs, have a significant amount of mercury present. The main problem is if these lights break, they can pose a health risk - anyone in the growing room can potentially inhale the mercury which can cause braind damage.

To give a specific range, ‘white LEDs’ will typically emit wavelengths only in the 450 - 550 nm range, or approximately 29.4% of the necessary photosynthetically active range (PAR) (550 nm - 450 nm / 720 nm - 380 nm).

Adding lights to your greenhouse can be a good option if you are not getting at least 6 hours of direct sunlight on your greenhouse and are not getting total of 12-18 hours.

Keep in mind however, that in a greenhouse, lighting should stay 20-40 Watts of light per square foot, and that light should be evenly distributed among leaves.

When using grow lights in your greenhouse you may not be able to get uniform light on all of your plants, and you may have difficulty getting uniform exposure for all of your crops.

Most vegetables and flowering plants by default will need a maximum of 12-16 hours of light per day. This means that your grow light will often be “on” for a similar period of time.

Some plants will actually do quite well when exposed to 24 hours of light, growing and blooming even faster than usual, whereas some plants will not do so well, and may fail to bloom or have stunted growth.

Photosynthesis depends on two biochemical processes, “light reaction” and “dark reaction”. Generally speaking, the light reaction is when the plant cells convert light to energy and the dark reaction is when the plant cells store the energy for later use.

Dark reactions, contrary do the name, many times do not actually require the plant to be exposed to just darkness. Some plants can undergo “dark reaction” storage of energy from light while exposed to light, and these are the plants that grow amazingly well in 24 hr light exposure situations.

As covered above, even incandescent bulbs can be used for growing plants indoors, but are not the best option. For most people, fluorescent, Metal Halide (MH), High Pressure Sodium (HPS), and LED lights will be the best options. For more in-depth details, re-visit the areas above!

For pretty much anyone besides the highly experimental grower, you will want to buy lights specifically designed as grow lights for indoor growing applications. Beyond the simple difference in effectiveness, you may be putting yourself at a safety risk by treating lights not designed to be grow lights in a grow light application.

This is one of the most common complaints our audience members e-mail in with feedback about. If you buy a grow light for the first time, odds are you will experience the burning of your plants.

- Adjust the height of your lights. Just because there is a recommended distance does not mean you should stick to the "guidelines" if you are burning your plants.

- Some readers have experimented with shade cloth if they have space constraints limiting how high they can hang lights. Be careful with this strategy as it can increase fire hazard.

- Ventilation and airflow. Most sites will suggest airflow as the solution to preventing overheating. This is a good first step to take if you are experiencing light to moderate browning or curling of leaves.

- fundamentally, all grow lights are replicating the sun. however grow lights are not as powerful as the sun, plan to run grow lights for 12-18 hours per day. Timers can help you manage this cycle.

- Fluorescent lights will not typically have color temperature / Kelvin rating listed on packaging in normal stores, instead they will be more loosely categorized into categories like "warm glow", "soft white", "bright white", "daylight" and "cool white" that each correspond to ratings

- When looking for fixtures / ballasts look for ones that have reflectors. Reflectors will help you significantly increase the efficiency of your lights. As an example, fluorescent lights emit light in all directions with equal intensity. Without a reflector, up to half of your light will not be shining where it needs to shine: on your crops.

- Roughly 2/3 of the your grow light expense should be the fixture/ballast and 1/3 of the expense should be the bulbs. other one time costs may involved for things like mounting.

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This lamp is very sturdy and has the Best gooseneck that I"ve every seen on a lamp. It is NOT the limp gooseneck you see on other lamps where you place the lamp in position, then it slowly Wilts like a dying flower. NOPE! This has a strong firm gooseneck that stays PUT exactly wherer you position it. If you"re using this for plants, this is a must because you need exact positioning to illuminate your plants so they will get the light they need. This lamp WILL ALLOW that Perfect Placement so your plants will thrive.

The clip is very strong is should solidly attach the lamp to a table, shelf, or other surface the the clip can grab. I was suprised at the heavy duty clip. You should never have any attachment problem with this lamp.

I purchased the 50 watt version. I was suprised at how BRIGHT this lower wattage version really is. Glad I didn"t order the 100 watt because it would have been too bright. Even with 50 watts, you must turn away to keep it from hurting your eyes.

Seller Customer Service is GREAT. My first lamp was defective. The selleer answered my query immediately and shipped a new lamp right away. I had the new lamp in only a few days. The seller is exceptional in customer service.

"Timer Function & Multiple Settings - this growing light offer the circular memory timer function with 3 options-4h/8h/12h. When keeping power, it can automatically turn on and off every day according your settings, no more manual operation for you."

What I expected is that once you set the timer the lamp would but ON for the timer period, then OFF for the timer period, then ON for the timer period... etc. etc. etc.

This lamp doe NOT work this way!!! It is based on a 24 hour cycle from the time you set the timer. For example, if you set a 4 hour timer it will turn ON immediately for 4 hours, then shut to OFF.

It will remain OFF for the next 20 hours until the next day when the time that you set the timer rolls around. Then, on Day 2, it wil burn for 4 hours then turn OFF.

Each time period you se