Plant Lighting Break Down-Myth about LED Grow Lights

Posted on Dec 10 , 2020

Summer residents are well aware of how important the correct lighting is for favorite indoor flowers or seedlings, as well as for adult plants in the greenhouse. Lack of light is often detrimental to many cultures, although some, of course, can get by with a small amount of sunlight. Most often, crops need additional illumination in winter, when the daylight hours are very short. And to improve conditions growing seedlings or indoor flowers, as well as crops living in year-round greenhouses, LED grow lights for plants should be used.


Indoor leafy vegetables growing with LED grow lights

Why do plants need light?

Before we study the main characteristics of LED grow lights and learn how to make them, let's recall the school course in biology and talk about why plants need light. Let's conduct a simple experiment - let's move any flower with green leaves deep into the apartment (where there is little sunlight) and observe it. After a while, it will be noted that the foliage of the plant began to gradually fall off. Moreover, if our experiment is continued, then the representative of the flora will simply die. It is logical to assume that the reason for the deterioration in the appearance of the plant was a lack of light.


Signs of a lack of light

The fact is that thanks to light, a certain biochemical process takes place inside plant cells, which also occurs with the participation of carbon dioxide and water - this is photosynthesis, which allows plants to form organic substances from inorganic substances. The cells in which it occurs are called chloroplasts, they contain the pigment chlorophyll, which is green - which is why most plants have green leaves.

Thus, sunlight is the energy source that triggers this complex nutritional pattern for green plants.


Photosynthesis of plants

Note! The process of photosynthesis occurs only during the day - at night, plants do not photosynthesize due to a lack of light. By the way, it is during the day that flora representatives absorb carbon dioxide and purify the air.

Interestingly, different plant species have different requirements for the intensity and quality of lighting. And artificial light sources must imitate real lighting, suitable for specific cultures. Usually, with a lack of light, the plants wither and stop growing, but there are also those cultures that, on the contrary, do not like excess sunlight - give them diffused, unobtrusive light.


How to properly place plant lighting

All types of crops can be divided into three main groups:

  • light-loving;

  • shade-tolerant;

  • shade-loving.

Most garden and indoor crops are plants that love light in sufficient quantities. It is also worth taking into account the fact that any plant organism can partially adapt to changing conditions. However, this ability differs in different species: some get used to a lack or excess of light quickly, others slowly. Due to this, completely different species can often exist in the same conditions. Also, in this case, some crops stop blooming or slightly change their appearance - for example, the leaves become thicker or thinner, growth slows down.


LED grow lights for leafy vegetables

Note! With excessive light, chlorophyll begins to partially break down, and therefore the leaves of some plant species begin to turn yellow. If the culture is not rearranged in a place with diffused and less intense light, then its green part will easily get burned.


Signs of excess light

But it is worth remembering that there are those species that categorically do not accept changes in environmental parameters. To grow them at home or in the garden, you will have to try and provide them with the right conditions.

Light spectra and light characteristics

Sunlight is electromagnetic radiation. The main characteristics of this radiation are dynamics during the day and the season, intensity, spectra included in it. It turns out that the spectra of light are different, and an ordinary light beam consists of several at once. Moreover, they (spectra) differ in wavelengths.


Recommended spectrum for indoor flowering plants

Table. The significance of various spectra in the life of plant organisms.

ColorsWavelength, nmValue for plants
Red and orange720-600 and respectively 620-595These are the main sources of energy for the process of photosynthesis; due to the intensity of their impact, the growth rate of the culture also changes. Also, an excess of rays of this spectrum will slow down the rate of transition of plants to the flowering period. Red rays accelerate the process of sprouting from seeds. The orange part of the spectrum has a beneficial effect on the fruiting process.
Purple and blue490-380Such parts of the spectrum take an active part in the process of photosynthesis, affect the rate of growth and development of culture. Stimulates the reactions that make proteins. Due to the rays of this part of the spectrum, the beginning of the flowering period begins earlier in wild plants under conditions of short daylight hours. Also, blue rays have a positive effect on the formation and growth of the root system, help to build up the correct crown.
Ultra-violet rays380-280Thanks to these parts of the spectrum, plants do not stretch, begin to produce some types of vitamins, and also become more resistant to temperature extremes. But in excess, ultraviolet light is very dangerous for plant organisms.
Yellow rays595-565Almost do not participate in the life of plant organisms.
Green rays565-490Similar to yellow rays.

Note! The most important parts of the spectrum for plants are PAR, photosynthetically active radiation, which has wavelengths in the 400 to 700 nm range.

By the way, the length of daylight hours is also not constant. For example, the longest daylight hours in temperate latitudes lasts 16 hours, and the shortest - only about 8. And that is why sometimes you have to resort to artificial lighting to provide plants with the amount of light they need.

Understand the impact of light spectrum for plant growing


Growing tomato with LED lights

Artificial lighting of plants

Artificial lighting for plants is necessary so that during a short daylight hours their development and growth does not stop, but seedlingit grew better and was old enough by the time of planting in open ground or greenhouse. Artificial lighting should provide the spectrum and intensity of radiation that crops need in accordance with their natural requirements.


LED grow lights for indoor home gardening

Artificial lighting of plants can be organized using various lighting devices. It was first used in 1868 by the botanist Andrei Famintsyn - he illuminated cultures with the help of lighted kerosene lamps. Now metal halide, fluorescent lamps, incandescent lamps, and also LEDs are used to illuminate plants. It is the latter that are the optimal solution when choosing options for organizing artificial lighting.

Features of LED grow lights

A grow light made on the basis of LEDs is considered one of the best options for organizing backlighting for plants. It is used for productive lighting of seedlings and flowers on windowsills, and can also use a whole system of grow lights to illuminate hugeindustrial greenhouses... It is possible to make the backlight as effective as possible using three types of bulbs: white, red and blue.


LED grow lights differ from conventional incandescent lamps, first of all, in the quality of the emitted light - it is balanced and selected in such a way that the plants are as comfortable as possible. That is, the radiation of the lamps is exclusively phytoactive.

Note! grow lights on LEDs shine not with white, but with violet-pink light, unpleasant for the human eye. But on the other hand, plants from this type of lighting grow much better and bloom / bear fruit well. Such light provides all their needs.


Light-emitting diode (LED) lamps for plants

The main advantages of LED lamps:

  • low energy consumption compared to other lighting options;

  • long service life;

  • the ability to work in high humidity conditions;

  • illumination of plants only with the rays they need;

  • lack of heating of air and objects around (therefore, LED grow lights can be installed right next to plants);

  • due to the previous point, the soil in which the plants live does not dry out quickly, which means that the frequency of watering decreases;

  • safety during operation (impossibility of explosions, absence of ultraviolet radiation, environmental friendliness);

  • no flicker;

  • the possibility of correcting the spectrum and adjusting the intensity of illumination depending on the life period of the plants.


LED grow light for plants 10W 3Red + 2Blu cartridge E27

The only drawback of LED grow lights is their high price. But if you calculate the costs over a certain period of time, then LED lamps will still turn out to be more profitable than other lighting fixtures. In addition, you can make a grow light yourself.


LED plant lighting

How to choose the right type of LED grow light for your plants?

When choosing an LED grow light, consider the following:

  • the lamp should not have radiation in the ultraviolet spectrum;

  • the size and power of the lamp should be correlated with the dimensions of the plantings;

  • pay attention to the number of LEDs in the lamp.

Large areas are best illuminated with phyto-floodlights, and small grow lights will be enough in rooms or on shelves. It is best to fix linear lighting fixtures on the windowsills.

It is important to know that a 5-15 W lamp will be enough to illuminate just a couple of plants, a 21-27 W lamp is suitable for illuminating an area up to 0.6 m 2 , and 36-45 W - up to 0.7 m 2 . Moreover, if the window where the seedlings stand faces north, then the number of lamps increases by 1.5 times. In the absence of daylight at all, the number of lamps is multiplied by 2.


LED lighting for plant indoors

Good advice

And finally, here are some practical tips to help you choose a lamp and use it correctly.

  • Vegetables are very fond of daylight and are best served with a permanent source of white light.

  • Seedlings prefer red and blue light (1: 2) before picking. This ratio stimulates the development of the root system and slows down the growth of the green part.

  • Seedlings after picking need some reduction in light intensity, and then they are highlighted with blue and red diodes (1: 1).

  • Flowering / fruit development works well under red light.

  • You can use green LEDs to decorate a green corner.

  • To make the light diffuse, you can use various reflectors (sheets on the walls, foil).

  • The grow light operating time is determined depending on weather conditions, the length of daylight hours.


Vertical farming LED lighting system

How will future vegetable grow under LED lighting in a vertical farming method?

Do not forget that alternation of dark and light periods is also important for plants. That is, they also have a night. Therefore, grow lights should be turned off regularly so that crops can take a break from endless photosynthesis. Moreover, the amount of light and darkness depends on the variety and type of plant. In general, both an experienced gardener and a beginner should buy or make a grow light with their own hands.

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