Without light and water, plants cannot maintain their vital activity – light takes part in photosynthesis and affects their growth. Artificial lighting for greenhouses should be as close as possible to the natural light of the ecological zone of a specific grown plant.

Rules of greenhouse lighting

Lighting systems play a primary role in the greenhouse business. Lighting costs have the greatest impact on the formation of the cost of the finished product. It is especially advisable to grow light- and heat-loving crops in the cold season.

lighting for greenhouses

Such crops as tomatoes, peppers, and lettuce need up to 18 hours of continuous lighting per day. The creation of such lighting is subject to special rules and has its own characteristics:

  • Lamps must create a high level of illumination and be designed for a long cycle of operation. The amount of light for a plant is more important than the spectrum.
  • Special lamps with narrow light spectrums are required for assimilation. For different stages of growth and different species, a spectrum will be effective.
  • The lighting system and placement of lamps and reflectors must provide the same illumination at any point on the horizontal plane.

To easily change the height of the lamp and its orientation in space, a suspended mounting option is used.

Types of greenhouse lighting

The use of artificial light sources in greenhouses is called light addition or supplemental lighting. In regions above 40 degrees north or south latitude, it cannot be done without it.

It can be a complement to natural lighting, thereby increasing the length of the plant’s day. The effectiveness of such additional lighting is the highest in the summer, but the large number of fruits in the open ground at this time makes it unprofitable.

greenhouse lighting

Round-the-clock use of supplemental lighting allows you to grow crops at any time of the year that are not typical of the open soil of a specific area, gives full control of lighting conditions, and allows you to place the greenhouse premises in any place.

Types of additional education:

  • Illumination from above is the main one and should first of all create a high level of brightness, and then the necessary spectrum. It is located on top and brings little light to the lower leaves of the plant.
  • Lateral illumination complements the main one, is located between the rows of plants and can improve yield by 15%.

Light sources for greenhouse lighting

Waves in the 400-700 nm range have a positive effect on plants:

  • 400-500 nm is blue, cold light – mandatory for regulation and substrate influence, affects shoot germination and vegetative growth;
  • 500-600 nm green – is not mandatory, but since it has a high degree of penetration, it is indicated for the growth and photosynthesis of thick leaves;
  • 600-700 nm red, warm light – necessary for acceleration of photosynthesis, flowering and fruiting phases, but in a homogeneous form leads to the occurrence of anomalies;
  • full-spectrum white daylight is versatile for both primary and secondary lighting, but not the most effective for increasing fertility.

In this regard, the following lamps have become the most widespread and used both in large industrial greenhouse farms and in small ones:

  • DNAT – a high-pressure sodium gas discharge lamp creates a red spectrum of light and partially blue. This is the cheapest and most efficient source – the light output is 130 lm/W. DNAT on a sintered electrode is an improved modification with a service life increased by 1.4 times. DNaZ is a mirror sodium lamp, the reflector improves the light distribution on the surface of the lamp. This type of lamps is also very popular in landscape lighting of trees.

Greenhouse lamps for DNaZ, DRIZ gas-discharge lamps must contain a ventilation system, a reflector, an EPRA and, in execution, meet the protection class IP50, 53.

    • DRY is a mercury arc lamp with emitting additives (sodium, thallium, indium nitrates) of the cold spectrum. Light output – 70-90 lm / W. DRIZ – DRIZ with an internal reflective coating.

lighting for greenhouses

  • Fluorescent ESLs do not have a pronounced spectrum, their light output is 50-70 lm / W. They are better suited for creating high daylight illumination in small greenhouses. In special ESLs, a coating is applied to the bulb to improve the spectrum, but such lamps are in short supply. I use it when it is necessary to create a light with a power of up to 300 W.
  • Incandescent lamps can only be used as an additional heat source, because they do not emit the blue spectrum and their light output is only 25 lm / W.
  • LED lamps can contain lamps of 5 basic light spectrums for photosynthesis (2 red, 2 blue and white), in them you can select the necessary ratio of colors and brightness most accurately, but the light level is weaker than sodium lamps. The peculiarity is that they do not heat up above 40 degrees.

A correctly selected lamp will maximally demonstrate the energy-saving properties of the lamp, which play a primary role in the greenhouse economy.

In general, the use of well-thought-out lighting schemes can increase productivity by up to 300%.

All of them are combined, as they offer the use of several types of lamps in one scheme. For small greenhouses, this is sodium fluorescent lighting, a budget option is fluorescent with incandescent lamps. The best so far has no analogues: use sodium lamps for the main additional lighting, and LED lamps, since they do not burn the plants, but only supplement the heating, to be placed directly between the rows as side additional lighting.

What should be the lighting for greenhouses?

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