In the zone of uncertain agriculture, which includes most of the Russian regions, part of the vegetables have to be grown in seedlings. Most gardeners prefer to grow seedlings on their own to be sure of its high quality. It’s easy, but there are some subtleties. Let’s figure out why seedlings need to be illuminated and how to organize it correctly.
All about additional lighting for seedlings
Why is it needed
Features of the organization of the backlight
Three ways to arrange additional lighting
– Lamps of different types
— Reflective screens
— Devices for improving illumination
Why do you need lighting for seedlings
With a lack of light, photochemical reactions inside the plant slow down or completely fade away, it experiences a lack of nutrients, gets sick and dies.
Gardeners begin to sow in late January-February. At this time, the daylight hours are short, the seedlings do not have enough natural light. They lose their bright green color, stretch out, become lethargic. All these are signs of a lack of light radiation. It is «treated» very simply — by backlighting. If the seedling immediately receives a sufficient amount of light, it actively develops the root and ground system. Her immunity is much higher, she quickly and easily takes root in a new place. It is necessary to make a decision on the arrangement of lighting, taking into account the conditions for growing seedlings.
Phyto-illumination is needed if
- Sowing occurs at the end of January-beginning of February.
- Crops with a long growing season or late varieties are grown.
- Seedlings stand on a windowsill facing the north side, or are generally removed from the window.
- There are many plants, and the space for growing them is limited.
You can do without backlight if
- The window sill or other place where the seedling boxes stand is well lit.
- Sowing is carried out in the second half of March or later.
- It is possible to compensate for the lack of light rays by top dressing.
- Early maturing varieties or crops with a short growing season are grown.
Features of the organization of additional illumination
There are norms for additional illumination of seedlings, which determine when and how much light rays the plant should receive. So, inexperienced gardeners sometimes organize round-the-clock illumination of seedlings. It hurts them a lot. A living organism needs a “day-night” cycle, this is inherent in it by nature. Therefore, a dark period must be present. It is best to turn on the lights for 2-3 hours at 6 am in the morning and at 5 pm in the evening.
This is the average time of using phyto-illumination. It depends on how light-loving the culture is. Tomatoes need the most light. Their daylight hours are 15-17 hours. Eggplants and peppers are less demanding, 10-15 hours are enough for them. Cabbage lasts 10-12 hours, strawberries — 12 hours, melons and watermelons 10-12 hours. If the weather is cloudy and there is clearly not enough light, it makes sense to turn on the lighting during the day.
3 ways to arrange additional lighting
Additional lighting can be arranged in different ways, we will analyze the most effective of them.
1. Illumination of seedlings at home with lamps
The easiest way to illuminate plants with additional light sources. It must be understood that none of them can completely replace the sun’s rays. But most of the time this is not necessary. Most of all, seedlings need blue and red rays, the rest of the spectrum is less important. Therefore, it is necessary to correctly determine which lamp can be used to illuminate seedlings. There may be several options.
They are used very rarely, because they give little benefit. Only 5% of electricity is converted into light energy, everything else «leaves» in the form of heat. Therefore, incandescent devices heat more than they shine. This is not good for seedlings. The soil in the boxes dries out quickly, there is a risk of thermal leaf burn. Light bulbs emit light waves of orange and yellow. Additional lighting is inefficient and costly.
Models are available with blue and red emission spectrum. Luminescent devices are economical and easy to install. During operation, they do not heat up, so they do not dry the soil and do not burn the plantings. They are produced in the form of long bulbs-flasks and spotlights. At the end of their service life, they lose power and begin to flicker. Require special disposal, because inside the flask is mercury.
metal halide light bulb
A type of gas-discharge light source. It gives a very powerful stream of light, at the same time it releases a lot of heat, therefore it dries the air and the soil mixture. Metal halide bulbs wear out fairly quickly. They are not safe. Explosion may occur on contact with moisture. Their use at home is not entirely justified. Expensive devices are more suitable for greenhouses or greenhouses.
Another option that is more often used in industrial agriculture. Mercury devices give a powerful luminous flux of the orange-red spectrum. Young plants do not like this very much, they do not have enough waves of blue. Light bulbs are expensive and unsafe because the bulb contains mercury. Requires special disposal.
Another type of gas discharge devices, but with a much lower price. Gives a powerful luminous flux in the orange-red spectrum. This is most suitable for flowering and fruiting plants. Sodium bulbs are characterized by high luminous efficiency, they are economical and durable. Sensitive to voltage drops in the network, unsafe.
Illumination of seedlings with LED lamps at home is considered the best way. LEDs are economical, durable, resistant to moisture and completely safe to use. With high light output, they do not have an incandescent effect: they do not heat up themselves and do not heat the air and objects around them.
LED phytolamps give radiation of a different spectrum. Bicolor emits blue and red light, in the multispectrum they are complemented by warm white and far red. Full spectrum devices use the entire range of luminosity. Bicolor is enough for seedlings, they will “get” the rest of the rays from daylight. The only drawback of such phytolamps is the pink-violet glow that irritates the human eye. It is better not to use them for a long time in a room where people are constantly present.
It is desirable to place the backlight on top of the seedling box. The lateral location of the light source will make the young shoots reach for the lighting fixture. The height of the lamp placement depends on its type and power. In addition, it is desirable to take into account the recommendations of the manufacturer. A light bulb placed too low can cause thermal burns to leaves and stems.
2. Reflective screens
To improve the illumination of seedling boxes, it is not necessary to use phytolamps. Reflective screens work well, redirecting light rays to seedlings. You can make them yourself.
A good effect is given by a box pasted over with a reflective film or foil. In order to make it, they take a cardboard box of a suitable size, cut off one of the sides and the top. The remaining sides are wrapped with reflective material. Foil strips can be glued, fixed with adhesive tape or with clothespins. The main thing is that they are securely held on the cardboard walls. Seedling boxes are placed inside the resulting box and placed on the windowsill.
Foil penofol works in a similar way. It is cut to the size of the window opening and fixed at the level of containers with seedlings. The material not only reflects light radiation, but also protects plantings from drafts and cold.
White paper sheets also reflect light rays. From paper, preferably dense, reflective screens are made. To do this, cut a strip along the length of the window sill. If the material is thin, it is better to make a cardboard base and stick paper on it. Thread loops or just laces are fixed in the upper part of the resulting screen. With their help, the product is attached to the window opening. Fix the screen so that there are containers with seedlings between it and the glass.
3. Devices for improving illumination
You can increase the illumination of seedlings in other ways. First of all, this is the correct placement relative to the light source. Usually the boxes are put on the windowsill. And so that they receive enough light, they build a small stand. The height of the stand depends on the dimensions of the window frame. It is important that it is sustainable.
Another solution is shelving. The arrangement of seedlings in tiers is especially good if there are a lot of them. It allows everyone to receive the dose of light necessary for normal development. Shelves are placed near the window or directly on the windowsill. It all depends on the size and shape of the structure. You can additionally put a reflective screen or screen. Window panes should be washed, even if they don’t seem dirty. Clear glass transmits 15% more light.
We figured out what kind of lighting is needed for seedlings and how to equip it yourself. You can get a good result even when using inexpensive lamps, you just need to place them correctly and not turn them on all night. In rooms with poor natural light, it is better to use combined options when artificial lighting is placed together with a reflective screen or screen. Otherwise, the plants will experience light hunger.