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Artificial lighting will only benefit seedlings when the right light source is selected. Natural lighting for plants is the most useful, but in early spring it is not enough. The seedling lamp used for supplementary illumination should emit two important spectra: blue and red. It is these colors that are absorbed by plants and affect their development.
Influence of different light spectra on plant development
Outdoors, green vegetation develops under sunlight. Waves of different colors and lengths are partially visible to human vision, but all color spectra are important for seedlings:
- The main role in the development of planting material is played by the red and blue light spectrum. The rays help to develop plant cells, the root system, and produce chlorophyll.
- Orange light is responsible for the future fruiting of indoor crops.
- The yellow and green spectrum, which is completely reflected from the foliage of plants, is considered useless. However, these colors contain the sun’s rays, which means that there is a small share of the benefits from them.
- Ultraviolet is harmful to all living things in large quantities. However, small doses of rays benefit the planting material. UV radiation is present in the sun’s rays and destroys pathogens of fungal and viral diseases.
- Infrared rays are completely absorbed by plants. Seedlings become lush, green, juicy.
No artificial light source is able to contain all the spectra, 100% replacing the sun’s rays. Usually, when organizing the backlight, the emphasis is on red and blue. However, the best lamps for seedlings are those that are capable of emitting white light, as well as IR and UV rays, in addition to the two main spectra.
The best sources of artificial light for additional illumination of planting material
Even the most expensive lamps for supplementing seedlings are not able to completely replace natural lighting. However, without artificial illumination it is impossible to grow a full-fledged planting material. It is optimal when the backlight is combined with natural light. You can achieve such results by placing seedlings on a windowsill or in a glass greenhouse.
Illumination helps to grow planting material even in rooms without window openings. Cultures grow under artificial illumination during the polar night. However, one white, red or blue seedling lamp will not do any good. We need specialized light sources that emit the entire composition of the spectrum and rays of different lengths.
Натриевые
Gas-discharge sodium lamps for growing seedlings produce several modifications. On sale there are models of the domestic manufacturer “Reflax”, as well as products of European brands. The gas-discharge lamp for illuminating seedlings does not harm a person, which allows it to be used in a greenhouse and a residential area.
If we dwell on the models of a domestic manufacturer, then a DNAZ with a power of 70 watts is suitable for indoor use. A feature of the product is the presence of a mirror reflector on a glass bulb. The lamp is able to make high-quality illumination of seedlings on a windowsill 1,5 m wide. The reflector creates a large projection angle of light rays and enhances them.
HPS serves as an analogue, but the product differs in the absence of a mirror reflector. With the same power of 70 W, the light spot will cover only 1 m of the area with planting material. Due to the small projection angle, one light bulb will have to be placed for every 1 m.
The considered positive and negative qualities of sodium light sources will help determine which lamps to use to illuminate seedlings.
Positive sides:
- radiation of a light spectrum suitable for the development of plants;
- long service life;
- low power consumption.
Negative sides:
- high price;
- for backlight you need a regulator;
- large dimensions.
Despite the emission of the most suitable spectrum, there is a lack of blue rays in the glow of a sodium bulb.
Phytoluminescent
The specialized pink seedling lamp belongs to the line of fluorescent light sources. The glow is well perceived by plants, and all spectra are completely absorbed. Phytoluminescent bulbs from different manufacturers differ in power and application features:
- Manufacturer Osram introduces a light source called Fluora. On 1 m2 of area with seedlings, 18 phytolamps with a power of XNUMX W are used.
- The domestic light source LFU-30 is installed one per 1 m of the length of the shelf with seedlings. Phytolamp power – 30 watts.
- The Enrich brand introduced a phytolamp, the glow of which slightly harms the eyesight. A plus is the presence of a mirror reflector. The downside is a short service life. With a power of 60 W, a lot of heat is released along with the light.
- Paulmann phytolamps are distinguished by a long service life. The power of light sources varies between 40-100 watts. The advantage is minimal heat generation.
The main advantage of phytoluminescent lamps is low power consumption, compact size, long service life, as well as radiation spectrum useful for seedlings.
The big disadvantage is the impossibility of using the backlight in the living room. The pink glow strongly irritates the organs of vision. Phytolamps are best installed in a greenhouse, non-residential room or covered with reflective screens.
Luminescent
A good energy-saving lamp for seedlings will come from a fluorescent housekeeper. However, such a light source is inconvenient due to the small capture area. Above the shelves with planting material, it is better to hang long tubular models of two pieces. The choice of this number is due to the low power of fluorescent lamps. Two tubes are placed from the tops of the seedlings at a distance of 15–35 cm.
The advantage of fluorescent tubes is low cost, economy, daylight emission. The disadvantage is that they emit a small amount of the red light spectrum. Mercury vapor poses a danger to humans if the flask breaks.
LEDs and phytolamps
The most economical and safe are led lamps for seedlings from a set of LEDs. You can even assemble the backlight yourself. You just need to buy red, blue and white LEDs, a power supply and solder the circuit from the details.
It is easier to give preference to the finished LED panel or use tape. The second option is even more convenient. The LED strip is glued to any support above the planting material along the entire length of the shelf.
The advantage of LED backlighting is low power consumption, as well as high light emission with low heat generation. The disadvantage is the high cost of lamps, individual LEDs and power supplies.
If you stay on LEDs, then bicolor lamps for seedlings will be the best choice. The phytolamp is an independent light source that is simply inserted into the cartridge. Lamps are produced with a different type of base, as well as differing in power and shape.
Depending on the LEDs used, phytolamps are divided into three groups:
- The red and blue spectrum is emitted by a bicolor lamp for seedlings, which affects the process of photosynthesis. Light wavelength – 660 and 450 nm. The direct purpose of the phytolamp is to illuminate young vegetation grown in any conditions.
- Phytolamp multispectrum is distinguished by the presence of additional spectra. A white glow has been added, as well as a distant red light. Radiation of the optimal set of light spectra stimulates the formation of inflorescences and fruiting in adult plants. Phytolamps are suitable for greenhouses and illumination of indoor flowers in case of lack of sunlight. Far red light passes through dense foliage. Phytolamps multispectrum well illuminate plants at a high density of planting.
- Phytolamps have a wide range – a full spectrum. They produce light sources with a power of 15 and 36 watts. The lamp is considered universal, but the bicolor model is inferior in efficiency, as well as spectrum peaks. The emitted artificial light in terms of indicators is as close as possible to natural light. Fitolamps are used to illuminate crops in a dark room throughout the entire growing season – from sowing to harvesting.
If the question arises, which lamp is better to highlight the seedlings, preference is given to a bicolor light source.
Induction
Induction bulbs are still little used in everyday life, but are considered an excellent option for artificial lighting. A feature is the emission of two spectra – blue and red. The advantage of light bulbs lies in the economy, versatility of the light spectrum, suitable for all types of seedlings. The maximum heating temperature during the glow is 75оC.
Lack of illumination with a conventional incandescent lamp
Beginning vegetable growers are interested in the question of whether it is possible to highlight seedlings with an ordinary lamp with a tungsten filament. As an independent source of illumination – it is impossible. A tungsten spiral transforms only 5% of the energy to create a light flux. The yellow-orange glow is not absorbed by plants. The large amount of heat generated overheats the plants and burns the leaves. If necessary, raise the temperature of the bulb can be used in tandem with other light sources.
The video shows the lamps for backlighting:
Lighting must be efficient, economical and safe. According to this principle, lamps are selected.