How to make a lamp for a polycarbonate greenhouse?

To get a good harvest or strong healthy seedlings, one greenhouse is not enough. It is necessary to create the necessary microclimate (humidity and temperature) and proper lighting in it. Today, the market offers a wide selection of phytolamps, the features of which are not so easy to understand. The information below will help.

Design Features

Depending on the type of lighting in greenhouses, there are differences in the design requirements for luminaires. For example, if you decide to use incandescent lamps for lighting, you need to place them high, since the heat generated by them can harm plants, especially seedlings. Before installing such lighting, consider how to protect the vegetation from excessive heat.

Important! The power of the light flux when changing the height of the light source, changes according to the " inverse square rule " . That is, if the lamp is located at a height of 1.5 m, the intensity of the flow near the floor will drop 2.25 times, the lamp located 2 meters from the floor will give 4 times less light. But the power of the lamp flow, installed at a height of 0.7 m, will give 2 times more light than the same lamp, located 1 meter from the surface.

The same can be said about halogen lighting devices, they also emit a lot of heat. Before equipping fixtures, the most suitable installation locations should be identified, based on this rule: Install moderate power devices (> 250 W) so that the distance to plants is 35–60 cm, for luminaires with a higher power distance should be about 90 cm

Fluorescent lamps do not heat up, but due to their large size, they must be installed in a certain way. It may be necessary to equip the greenhouse with additional mounting panels, since, for example, in greenhouses with a semicircular profile, it is problematic to install such devices vertically. The low cost of such lighting devices can offset the costs of their installation.

Metal-halogen devices are voltage-dependent (this also applies to halogen devices), so if the greenhouse is located in a holiday village with voltage fluctuations, you should think carefully before installing such lighting. In addition, frequent shutdown significantly reduces the service life of such devices. Most devices of this kind, with the exception of LEDs, do not tolerate high humidity.

LED (LED) technology is the most suitable lighting option for greenhouses. Such devices are small, their radiation is suitable for vegetation. You can place them at any distance from the crops grown, they are not afraid of moisture and are absolutely safe. In addition, such devices can be easily manufactured independently, they are lightweight and are not afraid of mechanical influences.

Did you know? The light of the blue spectrum promotes photosynthesis, warm red (orange) is needed during the flowering period, ultraviolet radiation stimulates the formation of vitamins and helps the hardening process. The light of the green-yellow spectrum can adversely affect the shape and thickness of the stems.

Types of lamps for greenhouses

To illuminate greenhouses, various types of lamps are used. They not only differ in the type of light source, but they have advantages and disadvantages, which are described in more detail below.

Incandescent lamp

It can be used to illuminate greenhouses, however, it is not recommended to use them in polycarbonate structures for the reason that lamps of this type emit only a red spectrum, which is not enough for the development of vegetable crops.

• Perhaps there are only two advantages to such lighting:
• low cost;
• due to strong heating, you can save on heating.

• Disadvantages of using incandescent lamps:
• emit only the red zone of the spectrum, which can harm the leaves and stems - deformation occurs, growth stops;
• Seedlings are poorly affected by strong heat, characteristic of lamps of this type (this does not apply to green crops);
• high power consumption.

Fluorescent lamps

This type of lamp is characterized by a wide range of light waves that can simulate natural sunlight. There are many models that differ in power and size.

You can arrange such lamps both vertically and horizontally. The only significant drawback is the fact that the voltage directly affects the brightness of the lamps, and if this value is below a certain level, the lamp is unlikely to turn on.

• Of the positive features of the use of lamps of this type can be identified as follows:
• white light emitted by such lamps is the most acceptable option for general (non-point) illumination;
• in the spectrum of these fixtures there is a necessary, but not excessive amount of infrared light needed by plants;
• in the lamp you can adjust the ratio of warm and cold rays, which can achieve excellent results for specific purposes (when growing certain crops);
• profitability;
• suitable for growing flowers;
• you can choose a device with narrowly targeted characteristics for specific purposes: to stimulate growth, the development of the ovaries.

Sodium lamps

Lamps whose mechanism of action is based on the use of sodium vapor as a luminous body are designed for use in greenhouses. Such light sources have a red spectrum, simulating sunlight well, but the blue spectrum in them is poorly represented. For this reason, they are not used to stimulate growth.

A distinctive feature of devices of this type is low power consumption and high light output, efficiency. Mirrors mounted nearby to reflect light will enhance the flow of light and increase its intensity.

• The advantages of this type of fixtures:
• low cost and energy consumption;
• durability (on average, up to 20, 000 hours);
• generate strong light with low energy consumption;
• due to the large amount of heat generated, it is possible to save on heating in winter;
• the red zone of the spectrum promotes flowering and fruiting;
• Efficiency is over 30%.

Important! You can’t use only one spectrum light for lighting a greenhouse, this negatively affects plants, and can cause a lack of crops and diseases.

• However, sodium lamps also have disadvantages:
• can get too hot, which does not affect seedlings in the best way;
• not safe enough.

Mercury lamps

Gas discharge (GR) lamps, where mercury vapor is used as an emitter of light waves. The optical radiation of such lamps has a beneficial effect on plants, simulating sunlight well. They present a UV spectrum that is suitable for overgrown or too elongated seedlings.

A significant drawback of such devices is the toxicity of mercury and its vapor. Such lamps should be operated carefully, and if the lamp crashes, complex demercurization is required, which can only be done by special services. In addition, in such a situation, everything that came into contact with mercury must be disposed of.

Is it worth it to equip the greenhouse with such lighting, you decide. Keep in mind, if even one lamp breaks, you can lose not only the crop, but also the greenhouse. In addition, the circumstance can adversely affect health and lead to expenses for demercurization and treatment.

Metal halide lamps

Lighting devices of this type are considered the most suitable for use in lighting greenhouses, since their spectrum is as close as possible to sunlight. They belong to high-pressure discharge lamps; mercury vapor is used as the luminous body, as in mercury lamps. The difference is that radiating elements - halogen salts - are added to these pairs.

• The advantages of such devices:
• long service life, provided that the device does not often turn on and off;
• high efficiency;
• small dimensions;
• excellent color rendering.

• The disadvantages of such lamps:
• have a high price, which makes their economic attractiveness low when used in small greenhouses;
• health hazard if the lamp breaks;
• strong dependence on the voltage;
• such lamps often burn out;
• the duration of use is directly affected by how often the lamps will turn on and off;
• it takes some time between power-up cycles, and also between power-up and light on.

LED bulbs

LED lighting fixtures (fittings) are manufactured using the most advanced LED technology. This is the most suitable option for artificial lighting of the greenhouse. A certain type of LEDs has a narrow emission spectrum, depending on the brand of its semiconductor (crystal). White light is obtained by sharing diodes of red, yellow and blue spectra.

• The advantages of using lamps of this technology include the following:
• have a long service life, with daily work for 16 hours are able, depending on the manufacturer, to serve for 5-18 years;
• the least energy-consuming among the possible options;
• You can vary the brightness level;
• LEDs are able to work at low voltage;
• do not radiate heat;
• tolerate mechanical stress;
• LED devices are not afraid of temperature changes and increased humidity;
• have the most suitable optical spectrum for the growth of a particular culture.

Read also about infrared heaters for the polycarbonate greenhouse.

The disadvantage is that the full coverage of a greenhouse of sufficient area is financially expensive. But, given the significant savings in electricity and the longevity of the lamps, equipment costs will soon pay off.

Crop Application

The use of additional lighting in greenhouses will not be superfluous when growing cucumbers and tomatoes, onions, peppers, flowers and other plants. You can do without it, but the results will be worse. Below are the rules and recommendations that should be remembered when growing various crops.

Cucumbers:

• additional lighting recommended;
• lighting should have a blue spectrum, during flowering and ovary formation - red;
• natural lighting should smoothly turn into artificial without gaps, this can provide relay greenhouse equipment;
• the culture needs 12 light hours per day (natural + artificial lighting);
• 1/4 of the day in the greenhouse should be dark;
• during the use of artificial lighting, the temperature regime should be controlled within + 8 ° C.

Tomatoes:

• additional lighting after seedling emergence is recommended;
• in the first time after seedling germination, 20 light hours per day are needed, the duration gradually decreases to 12 hours;
• Tomatoes need directional rather than diffuse lighting;
• the lighting of the greenhouse is contraindicated round the clock, as this is fraught with the development of diseases.

Did you know? LED lamps have an efficiency of more than 93%, have the highest light output - up to 100 Lm / W, while the index of fluorescent lamps does not reach 75 Lm / W.

Strawberry:

• during breeding, fluorescent lamps (1 m long, power 40–50 W) have proven themselves well. Such a device is sufficient for normal additional illumination of an area of ​​4-6 m².
• periodic change of location of containers with seedlings is necessary.
• within 13-14 hours, it is necessary to illuminate a warm spectrum with an average brightness of 140 lux.

Onion. Experts say that natural lighting for growing onions is enough, but the greens will have a pale appearance. Phytolamps, as an additional source of light, will help to cope with this problem: the greens will become more elastic, and the color bright.

Wild strawberries . Although the formation of buds of strawberries is beneficially influenced by short daylight hours, during the period of inflorescence formation, the plant needs illumination of 13-17 hours a day. In natural nature, such conditions are possible no earlier than mid-spring, so that in May strawberries already bloom, and in June you can already enjoy a berry. Using additional lighting in the greenhouse, delicious strawberries can be tasted at an earlier date, while the abundance of the crop will pleasantly surprise you.

How to make a lamp for a greenhouse with your own hands?

It is possible to independently manufacture additional lighting devices for the greenhouse. If you have some skills, and following the instructions below, this is not difficult.

Before proceeding with artificial lighting equipment, it is necessary to take into account such factors:

• the height at which the lighting devices will be located;
• type of device and its power;
• cultivated plants;
• greenhouse area to be lit (often this indicator is less than the total area);
• time of year and daylight hours.

Depending on the degree of necessary illumination, plants can be divided into 3 groups:

1. Which need bright light (15–20 thousand Lux). These crops in natural conditions grow in an open, brightly lit area (roses, exotic fruits).
2. Lighting a moderate level - 10-17 thousand Lux.
3. Twilight - from 5 to 10 thousand Lux.

In agrotechnical reference books you can find out the amount of light needed for a particular species. The smallest value necessary for the normal functioning of the cultivated crops is 6–8 thousand Lux. This degree of illumination is easily achieved with instruments with a specific power of 60–100 W / m.

Read more about the features and types of lighting for greenhouses.

Given the amount of light required by the culture you grow, you can calculate the light flow rate and the number of devices that can provide it.

Do this according to the following formula:

X = L × S : K, where:

X is the created light flux; L is the level of lighting needed by the plant (the indicator is taken from the directory); S - greenhouse area requiring lighting; K is the reflection coefficient (lamps with an external reflector have K = 0.4, with an internal reflector of 0.8).

Using this formula, you can calculate the light flux needed by crops that need 12 thousand Lux, which grow in a greenhouse with an area of ​​20 m, and the number of lighting devices:

X = 12000 × 20: 0.4 = 600000 lumens (lm), so much light is needed for these conditions.

Now, based on this indicator, it is possible to calculate the required number of lamps to create such a light flux, using the example of NaNT 400 sodium lamps. One such lamp gives a flow of 48, 000 lm, so 600, 000: 48, 000 = 12. It is this number of light devices that will be needed to satisfy the above conditions . Now you need to determine the desired height of the lighting fixtures.

It can be found most accurately with the help of a luxometer, but you can also apply the data of directories:

• Above one seedling you can place a light source with a power of 20-30 W, at a distance of 6-30 cm;
• a small group of plants can be illuminated by a device with a power of 60–100 W, located 45–60 cm above the tops of seedlings;
• Winter greenhouses with large areas of lighting are equipped with 250 W luminaires located at a height of 1-2 meters.

Important! In order to enhance the light flow, a reflector (principle of a searchlight) is used, which purposefully focuses and enhances the flow. Reflectors are required if low power lamps are used.

It is necessary to calculate the distance between the lighting device and the plant with special care, otherwise the seedlings may get burned.

Preliminary measures for equipping phytolamps are as follows:

1. Calculation of the level of necessary illumination and the number of fixtures needed for its creation.
2. Drawing up a plan for the placement of devices and power wiring.
3. Calculation of the required cross-section of electrical cables and associated fuses.
4. Installation, according to the drawn up plan, lighting devices, junction boxes, switchboard. Lamps should be mounted with adjustable height.

When fixtures, wiring and shields with circuit breakers are installed inside the greenhouse, it is time to move on to supplying electricity to the devices.

Do this in the following sequence:

1. Start by bringing the power cable to the greenhouse. The cable can be conducted through the air (the distance between the posts on average 2.5 m), or laid underground (ditch depth 0.8 m). If you decide to lay power underground, use an armored cable with a good insulating layer. After the cable is laid, it is covered with two layers of slate on top (to avoid possible damage), after which it is covered with earth, periodically well priming when burying.
2. If you decide to pull the power wire through the air, lay the line so that there are no trees nearby.
3. Now connect the cable to the electrical box. It must be equipped with a circuit breaker and a circuit breaker. Devices should be selected moisture resistant. As a result of the actions taken, at the exit from the electrical panel (do not forget to ground it) there must be a current of the required power.
4. Теперь следует соединить смонтированную в теплице систему с электропитанием. Все соединения между проводами должны быть прочными и надёжными, для этого лучше применить обжимные клемники. Помните, что вся система расположена в помещении с высокой влажностью.
5. Когда все вышеперечисленные действия выполнены, и вы проверили, что система нормально работает, её необходимо отрегулировать, меняя высоту расположения ламп или мощность подаваемого тока. Для измерения потока света следует использовать люксометр.

Для получения обильного урожая в теплице, как и для выращивания здоровой рассады, освещение должно быть сбалансированным. Это означает, что необходимо в нужной степени сочетать естественный солнечный свет и дополнительное освещение. Сложно получить хороший урожай без применения дополнительного освещения, и практически невозможно этого добиться без естественного освещения, используя исключительно искусственное.