A growing light or plant light is an artificial light source, generally electric light, designed to stimulate plant growth by emitting the right light for photosynthesis. Grow lights are used in applications where there is no light occurring naturally, or where additional light is required. For example, in winter when the available daylight hours may not be enough for the desired plant growth, the lamp is used to prolong the time the plant receives light. If plants do not receive enough light, they will grow long and thin.
Growing lights either try to provide a spectrum of light similar to the sun, or to provide a more customized spectrum to the needs of cultivated plants. The outdoor conditions are imitated with the various colors, temperatures and spectral output of the growing light, as well as varying the lumen output (intensity) of the lamp. Depending on the type of cultivated plant, the cultivation stage (eg the germination phase/vegetative or the flowering/fruiting phase), and the photoperiode required by the plant, the specified spectrum range, luminous efficacy and desired color temperature to be used. with plants and periods of time.
Botanist from Russia, Andrei Famintsyn was the first to use artificial light for planting and crop research (1868).
Video Grow light
General use
Growing lights are used for horticulture, indoor gardening, plant propagation and food production, including indoor hydroponics and aquatic plants. Although most light bulbs are used at the industrial level, they can also be used in households.
According to the inverse square law, the intensity of light emanating from the point source (in this case the light bulb) reaching the surface inversely proportional to the square of the surface distance from the source (if an object is two times farther, receiving only a quarter of light) which is a serious obstacle to growers in the room, and many techniques are used to use light as efficiently as possible. Such reflectors are often used in lamps to maximize light efficiency. Plants or lamps are moved as close as possible so that they receive the same lighting and that all the light coming from the lamp falls on the plant rather than in the surrounding area.
Different types of bulbs can be used as growing lamps, such as incandescent lamps, fluorescent lamps, high intensity discharge lamps (HIDs), and light-emitting diodes (LEDs). Currently, the most widely used lights for professional use are HID and fluorescent. Individual flower and vegetable growers usually use HID/SON and metal halide (MH) lamps, but fluorescent and LED lamps replace metal halides due to their efficiency and economy.
Metal halide lamps are regularly used for the vegetative phase of plant growth, as they emit larger amounts of blue and ultraviolet radiation. With the introduction of ceramic metal halide lighting and full-spectrum metal halide lighting, they are increasingly being used as exclusive light sources for vegetative and reproductive growth stages. Blue spectrum light can trigger a larger vegetation response in plants.
High-pressure sodium lamps are also used as a single light source throughout the vegetative and reproductive stages. In addition, they can be used as a full spectrum lighting amendment during the reproductive phase. The red light spectrum can trigger a larger flowering response in the plant. If a high-pressure sodium lamp is used for the vegetative phase, the plant grows slightly faster, but will have longer segments, and may be longer overall.
In recent years LED technology has been introduced into the growing light market. By designing growing light indoors using diodes, certain wavelengths of light can be produced. NASA has been testing LED grow lights for their high efficiency in growing food in space for space colonization. The findings show that plants are affected by light in the red, green and blue parts of the visible light spectrum.
Maps Grow light
General type
High Intensity Discharge (HID)
While fluorescent lighting is used to be the most common indoor growing type of light, HID lamps are now the most popular. High intensity discharge lamps have high lumen per watt efficiency. There are several types of HID lamps including mercury vapor, metal halide, high pressure sodium and conversion lamps. Metal halide lamps and HPS produce a color spectrum somewhat comparable to the sun and can be used for growing crops. Mercury vapor lamps are the first type of HIDs and are widely used for street lighting, but when indoor gardening they produce a relatively poor spectrum for plant growth so most have been replaced by other HIDs for growing plants.
All HID lamps grow in need of a ballast to operate, and each ballast has a certain wattage. Popular watt HID covers 150W, 250W, 400W, 600W, and 1000W. Of all sizes, the 600W HID lamp is the most electrically efficient as far as light is produced, followed by 1000W. HPS 600W produces 7% more light (watts-for-watt) than HPS 1000W.
Although all HID lamps work on the same principle, different types of lamps have different initial and voltage requirements, as well as different operating and physical characteristics. Because this bulb will not work properly unless it uses a suitable ballast, even if the bulb will physically connect in. In addition to producing lower light levels, incompatible light bulbs and ballasts will stop working earlier, or may even burn directly..
Metal splitting metal halide (MH)
Metal halide lamps are a type of HID lamp that emits light in the blue and purple parts of the light spectrum, which are similar to the light that is available outdoors during the spring. Because their light mimics the spectrum of the sun's colors, some farmers find that plants look more fun under metal halide than other types of HID bulbs like HPS that change the color of plants. Therefore, it is more common for metal halides to be used when plants are on display at home (eg with ornamental plants) and natural colors are preferred. Metal halide lamps need to be replaced about once a year, compared to HPS lamps that last twice as long.
Metal halide lamps are widely used in the horticultural industry and are well suited to supporting plants at an earlier stage of development by promoting stronger roots, better disease resistance and more compact growth. The blue spectrum of light promotes dense and leafy growth and may be more suitable for growing vegetative plants with many leaves.
A metal halide bulb produces 60-125 lumens/watt, depending on the wattage of the bulb.
They are now being made for digital ballasts in early versions of pulses, which have higher electrical efficiency (up to 110 lumens per watt) and faster heating. One common example of a metal halide starting pulse is metal halide ceramics (CMH). Pulse start metal halide lamps can come in the desired spectrum from cold white (7000 K) to warm white (3000 K) and even ultraviolet-heavy (10,000 K).
Metal Ceramic Halide (CMH, CDM)
Ceramic metal halide lamp (CMH) is a relatively new type of HID lamp, and this technology is named by several names when it comes to growing lamps, including ceramic disposal of metal halides (CDM), ceramic arc metal halide .
Ceramic metal halide lamps start with pulse starters, just like any other "pulse start" metal halide. The disposal of ceramic metal halide lamps is contained in a type of ceramic material known as polycrystalline alumina (PCA), which is similar to the material used for HPS. PCA reduces sodium loss, which in turn reduces shifts in color and variation compared to standard MH lamps. Horticultural CDM offerings from companies like Philips have proven to be an effective light source of growth for applications with medium watt.
Combination MH and HPS ("Dual arc")
The combination of HPS/MH lamps combines high-pressure metal and sodium halides in the same bulb, providing the red and blue spectrum in a single HID lamp. The combination of blue and red metal halides of high-pressure sodium lamps is an attempt to provide a very wide spectrum in a single lamp. This allows for a single bulb solution throughout the plant life cycle, from vegetative growth to flowering. There is a potential sacrifice for the convenience of a single bulb in terms of results. However there are some qualitative benefits that come for a wider spectrum of light.
High-Pressure_Sodium_.28HPS.29 "> High Pressure Sodium (HPS)
High-pressure sodium lamps are a type of HID lighting that is more efficient than metal halides. The HPS light emits light in yellow/red look and small parts of all other visible lights. Because HPS grow lights give more energy in the red part of the light spectrum, they can promote bloom and fruition. They are used as a supplement for natural daylight in greenhouse lighting and full metal halide lighting or, as a stand-alone light source for growing space.
HPS bulbs are sold in the following sizes: 150W, 250W, 400W, 600W and 1000W. Of all sizes, the HID 600W lamp is the most efficiently electrically as far as the light is generated, followed by 1000W. HPS 600W produces 7% more light (watt-for-watt) than HPS 1000W.
The EPS bulb produces 60-140 lumens/watts, depending on the light bulb.
Plants grown under HPS lamps tend to extend from the lack of blue/ultraviolet radiation. Modern HPS hoods have a much better adjustable spectrum for plant growth. The majority of HPS lamps while providing good growth, offer poor rendering color index rendering (CRI). As a result, the yellowish light of the HPS can make indoor plant health monitoring more difficult. CRI is not a problem when HPS lamps are used as additional lighting in greenhouses that utilize natural light (which offsets the HPS yellow light).
High-pressure sodium lamps have a long bulb life, and six times more light output per watt of energy consumed than standard incandescent bulbs. 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 more preferred greenhouse lights. However, at higher latitudes, there are periods of years where sunlight is scarce, and additional light sources are indicated for proper growth. HPS lamps can cause distinctive infrared and optical signatures, which can attract insects or other pest species; this in turn can threaten the growing crop. High-pressure sodium lamps emit a lot of heat, which can lead to leggier growth, although this can be controlled by using special special air-ball reflectors or cages.
Conversion light
Conversion lamps are manufactured so that they work with either MH or HPS ballasts. A grower can run a HPS conversion ball on a MH ballast, or a MH conversion bulb in an HPS ballast. The difference between a ballast is a ballast HPS has a igniter that ignites sodium in a HPS ball, while a MH ballast does not. Therefore, all electric ballasts can turn on MH lights, but only Switchable or HPS ballasts can fire HPS ball without conversion balls. Usually a metal halide conversion bulb will be used in HPS ballasts because the MH conversion bulb is more common.
Replaceable Reply
Switchable ballasts are HID ballasts that can be used with metal halide or HPS bulbs with the equivalent wattage. So a 600w Switchable ballast will work with either 600W MH or HPS. Farmers use this equipment to spread and vegetatively grown plants under a metal halide, then switch to a high-pressure sodium bulb for the fruiting or flowering stages of plant growth. To change between the lights, only light bulbs need to be changed and the switch needs to be set to the appropriate settings.
LEDs (Light Emitting Diodes)
The growing LED light consists of a light-emitting diode, usually in a casing with built-in heat sink and fan. The growing LED light usually does not require a separate ballast and can be plugged directly into a standard power socket.
The LED lights vary in color depending on the intended use. It is known from the study of photomorphogenesis that the spectrum of green, red, far-red and blue light has an effect on root formation, plant growth, and flowering, but there is not enough scientific study or field trials using LED lights to grow for specific color ratio recommendations for optimal plant growth under growing LED lights. It has been shown that many plants will grow normally if given a red and blue light. However, many studies show that red and blue lights only provide the most cost-efficient method of growth, plant growth is still better under light that comes with a green color.
The white LED lights grow providing a full light spectrum designed to mimic natural light, providing a balanced spectrum of red, blue and green spectrum. The spectrum used varies, however, the white LED lights are grown designed to emit red and blue light in amounts equal to the added green light to appear white. The white LED lights are grown often used for additional lighting in homes and office spaces.
A large number of plant species have been assessed in greenhouse trials to ensure that plants have higher quality in biomaterials and biochemicals are even higher or comparable to field conditions. The performance of mint, basil, lentil, lettuce, cabbage, parsley, carrots is measured by assessing plant health and strength and success in promoting growth. Promote with large flowering of select ornamentals including primula, marigold, stock also note.
In tests conducted by Philips Lighting on growing LED lights to find the optimal light recipes for growing various vegetables in greenhouses, they found that the following light aspects affect plant growth (photosynthesis) and plant development (morphology): light intensity, total light from time to time, the light at which time of day, light/dark period per day, the quality of light (spectrum), the direction of light and the distribution of light above the plant. But it is noted that in tests between tomatoes, mini cucumbers and peppers, the optimal light recipes are not the same for all plants, and vary depending on the crop and the area, so now they should optimize LED lighting in greenhouses based on trials and errors. They have shown that LED lights affect resistance to disease, taste and nutritional levels, but by 2014 they have not found a practical way to use that information.
The diodes used in early LED lighting designs are typically 1/3 watt to 1 watt. However, higher watt diodes such as 3 watts and 5 watt diodes are now commonly used in growing LED lights. for very dense areas, a COB chip between 10 watts and 100 watts can be used. Due to heat dissipation, these chips are often less efficient.
The growing LED light must be kept at least 12 inches (30 cm) from the plant to prevent the leaves from burning.
Historically, LED lighting is very expensive, but the cost is greatly reduced over time, and their longevity has made them more popular. Growing LED lights are often priced higher, watt-to-watt, than other LED lights, because of the design features that help them become more energy efficient and last longer. Specifically, as LED lights grow with relatively high power, growing LED lights are often equipped with cooling systems, since low temperatures increase brightness and long life. LEDs typically last for 50,000 - 90,000 hours until LM-70 is reached.
Fluorescent
The fluorescent lamps come in various form factors, including long, thinner bulbs as well as smaller spiral balls (compact fluorescent lights). Fluorescent lights are available in color temperatures ranging from 2700 ° C to 10,000 ° C. Luminous efficacy ranges from 30 lm/W to 90 lm/W. The two main types of fluorescent lamps used for growing crops are tubular lights and lamps compact fluorescent.
Fluorescent lights with Tube style
Fluorescent lamps grow not as strong as HID bulbs and are usually used to grow vegetables and herbs indoors, or to start seeds to get an initial jump on spring planting. A ballast is required to run this type of fluorescent lamp.
Standard fluorescent lighting comes in several form factors, including T5, T8, and T12. The brightest version is T5. T8 and T12 are less strong and more suitable for plants with lower light requirements. High output fluorescent lamps produce twice as much light than standard fluorescent lamps. High-output fluorescent fixtures have very thin profiles, making them useful in restricted areas vertically.
Fluorescent has an average lifespan of up to 20,000 hours. Fluorescent lamps produce 33-100 lumens/watt, depending on form factor and wattage.
Compact Fluorescent Lamps (CFL)
Compact Fluorescent Lights are smaller versions of fluorescent lamps originally designed as pre-heat lamps, but are now available in quick-start form. CFLs mostly replace incandescent light bulbs in households because they last longer and are much more electrically efficient. In some cases, CFL is also used as a growing lamp. Like standard fluorescent lamps, they are useful for propagation and situations where relatively low light levels are required.
While standard CFLs of small size can be used for growing crops, there are also CFL lamps made especially for growing plants. Often these compact fluorescent lamps are sold with specially designed reflectors that direct light to plants, such as HID lamps. CFLs grow common lamp sizes including 125W, 200W, 250W and 300W.
Unlike HID lamps, CFLs go into standard mogul socket lamps and do not need separate ballasts.
Compact fluorescent lights are available in warm/red versions (2700 Â ° K), full-spectrum or daylight (5000 Â ° K) and cool/blue (6500 Â ° K). A warm red spectrum is recommended for flowering, and a cool blue spectrum is recommended for vegetative growth.
The lifespan that can be used for compact fluorescent lamps is about 10,000 hours. The CFL produces 44-80 lumens/watts, depending on the light bulb.
Examples of lumens and lumens/watt for different CFL sizes:
Color spectrum
Different growing lamps produce different light spectra. The pattern of plant growth can respond to the color spectrum of light, a process completely separate from photosynthesis known as photomorphogenesis.
Natural light has a high color temperature (about 5000-5800 Â ° K). The color of visible light varies according to the weather and the angle of the Sun, and the amount of light (measured in lumens) stimulates photosynthesis. The distance from the sun has little effect on seasonal changes in the quality and quantity of light and plant behavior generated during the season. The Earth's axis is not perpendicular to the plane of its orbit around the sun. For half a year the north pole is tilted toward the sun so that the northern hemisphere gets direct sunlight and the southern hemisphere gets a tilted sunlight that must move through the atmosphere more before reaching the Earth's surface. In the other half of the year, this is reversed. The visible spectrum of light emitted by the sun does not change, only its quantity (more during summer and less in winter) and the overall quality of light reaching the Earth's surface. Some additional LED lights grown in a vertical greenhouse produce a combination of only red and blue wavelengths. The color rendering index facilitates the comparison of how close the light matches to the natural colors of ordinary sunlight.
The ability of the plants to absorb light varies with species and the environment; however, the general measurement for the quality of light as it affects the plant is the value of PAR, or the Active Radiation of Photosynthetic.
There have been several experiments using LEDs to grow crops, and it has been shown that plants need red and blue light for healthy growth. From experiments it has consistently found that plants grown just beneath red LEDs (660Ã, nm, long waves) of spectrum grow poorly with leaf deformity, although adding a small amount of blue allows most plants to grow normally.
Some reports indicate that the minimum blue light requirements of 15-30 Ã, ÂμmolÃ,m -2 Ã, Â · s -1 are required for normal development in some plant species.
Many studies show that even with the blue light added to the red LED, plant growth is still better under white light, or light that comes with a green color. Neil C Yorio shows that by adding 10% of the blue light (400 to 500 nm) to the red light (660 nm) in the LED, certain plants such as lettuce and wheat grow normally, producing the same dry weight as the control plants grown under the spectrum rays full.. However, other plants such as radish and spinach grow poorly, and although they are better under 10% blue light than red light, they still produce much lower dry weight than controlling plants under full-spectrum rays. Yorio speculates there may be additional spectrum of light that some plants need for optimal growth.
Greg D. Goins examined the growth and yield of Arabidopsis seed plants growing from seed to seed under a red LED light with 0%, 1%, or 10% blue light spectrum. Arabidopsis plants growing under just red LEDS alone yield seeds, but have unhealthy leaves, and the plants take twice as long to start flowering as compared to other plants in experiments that have access to blue light. Plants grown with 10% blue light produce half the seeds of those growing under the full spectrum, and those with 0% or 1% blue light produce one tenth of the seeds from the full spectrum plant. The seeds all germinate at a high level beneath all types of light tested.
Hyeon-Hye Kim points out that adding 24% of green light (500-600 Â ° nm) to red and blue LEDs increases the growth of lettuce plants. This RGB treated plant not only produces higher dry and wet weights and a larger leaf area than plants grown with only red and blue LEDs, but also produces more than control plants planted under cold, white fluorescent lamps, which is a common standard for full spectrum light in plant research. He reports that adding green lights also makes it easier to see if the plants are healthy because the leaves appear green and normal. However, giving almost all green light (86%) to lettuce yields lower yields than all other groups.
The National Aeronautics and Space Administration's (NASA) Biological Sciences research group has concluded that a light source consisting of more than 50% green causes a decrease in plant growth, while combinations including up to 24% green increase growth for some species. The green light has been shown to affect plant processes through both cryptochrome-dependent and cryptochrome-independent means. Generally, the green light effect is the opposite of that directed by red and blue wavebands, and it's speculated that the green light works with orchestration with red and blue.
Need for plant light
The manufacturer's specific requirements determine which lighting is most appropriate for optimal growth. If the plant does not get enough light, it will not grow, regardless of other conditions. Most plants use chlorophyll that mostly reflects green light, but absorbs red and blue light well. Vegetables grow best in strong sunlight, and to thrive indoors they require sufficient light levels, while leaf plants (eg Philodendron ) grow in full shade and can grow normally with far-flung light levels lower.
The use of lamps grows depending on the plant growth phase. In general, during the hatching/cloning phase, the plant should receive 16 hours at, 8-hour off. The vegetative phase usually takes 18 hours, and 6 hours off. During the final stages, flower growth, continued to grow lights for 12 hours and 12 hours off is recommended.
Photoperiodism
In addition, many plants also require dark and bright periods, an effect known as photoperiodism, to trigger flowering. Therefore, the lamp can be switched on or off at the specified time. The optimal photo/dark period ratios depend on plant species and varieties, as some prefer a long day and a short night and others prefer an opposing or intermediate "day length".
Much emphasis is placed on photoperiods when discussing crop development. However, it is the number of hours of darkness that affect the response of plants to the length of the day. In general, "short-day" is the day on which the photoperiode is no more than 12 hours. A "long-day" is a day in which the photoperiode is not less than 14 hours. Short-term plants are the ones that flower when the length of the day is less than the critical duration. Long-lived plants are plants that only flower if the photoperiode is greater than the critical duration. Neutral plants of the day are flowering without fotoperiode.
Plants that flower in response to a photoperiode may have a facultative or mandatory response. The facultative response means that the plant will eventually flower regardless of the photoperiode, but will bloom more quickly if it grows under a certain photoperiode. A meaningful response means that the plant will only flower if planted under a certain photoperiode.
Photosynthetic Active Radiation (PAR)
Lux and lumens are commonly used to measure light levels, but they are photometric units that measure the intensity of light perceived by the human eye.
The level of light spectrum that plants can use for photosynthesis is similar to, but not equal to what is measured by the lumens. Therefore, when it comes to measuring the amount of light available to plants for photosynthesis, biologists often measure the amount of radiation actively photosynthetically (PAR) received by plants. PAR sets the spectral range of solar radiation from 400 to 700 nanometers, which in general corresponds to the spectral range that photosynthetic organisms can use in photosynthesis.
Irradiance PAR can be expressed in units of energy flux (W/m 2 ), which is relevant in the consideration of the energy balance for photosynthetic organisms. However, photosynthesis is a quantum process and the photosynthetic chemical reactions are more dependent on the number of photons than the amount of energy contained in photons. Therefore, plant biologists often measure PAR using the number of photons in the range 400-700 m received by the surface for a certain amount of time, or Photointetic Photon Flux Density (PPFD). This is usually measured using m -2 s -1 .
According to one of the growing lamp manufacturers, plants need at least a light level between 100 and 800? Mol m -2 s -1 . For daylight (5800 K), this is equivalent to 5800 to 46.000 lm/m 2 .
See also
- Chlorophyll
- High Pressure Sodium Lamp
- Fluorescent Lamps
- Compact Fluorescent Lamp
References
External Links
- Does the Plant Need UV Light?
Source of the article : Wikipedia
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