How does light affect plant growth?

Light is the most important variable affecting plant growth. If plants do not receive enough light, they will not grow at their maximum rate or reach their maximum potential, no matter how many other variables they receive – water, growth medium, or fertilizer. And light starts the growth cycle of plants and supports plant development. Without light, plants cannot grow, reproduce and find enough oxygen to sustain life.

Three basic needs for plant survival. Light, water and carbon dioxide. Plants use water and carbon dioxide to produce food. Plants use energy from sunlight or artificial light sources to convert carbon dioxide, soil nutrients and water into organic compounds. This process of forming the basis of plant life is called photosynthesis. Light is the driving force of photosynthesis, which is a plant process that converts sunlight into chemical energy. In the process of photosynthesis, water is decomposed into oxygen and hydrogen in chemical reaction, and carbon dioxide (CO2) is converted into sugar.

The general rule of thumb is that 1% more light will increase plant growth by a similar percentage, thereby increasing yield by 1%. All plants need light and carbon dioxide for photosynthesis. Sufficient spacing between plants will ensure that each plant receives sufficient light in the greenhouse. But plants that lack light tend to grow upward and seek light. This is the survival mechanism of plants. If the plant does not get enough light; Leaves turn yellow, shrink, and stems weaken. Plants that do not get enough light will eventually lose color and die. Plants exposed to too much light will also have a negative impact on plant growth.

White light includes red, blue, green, yellow and other light colors. Plants absorb or reflect some colors for photosynthesis. And the color of different light is also different for plant growth. For example, blue light is very important for the first stage of plant growth. The flowering stage requires red light.

Natural sunlight is the best way for plants to grow. Sunlight provides the true balance of blue and red light that plants need. This balance is particularly important for plant growth and flowering. However, there are seasonal differences in natural light, such as short sunshine time in winter. And different plants need different sunshine time, so there is artificial light to meet the needs of plant growth. And the working principle of artificial light source is also made by simulating sunlight. For example, fluorescent lamps, incandescent lamps, metal halide lamps, high-pressure sodium lamps and LED lamps are artificial light sources used to support plant growth. Artificial light source can control the growth of plants and produce faster.

In addition, the following factors are also extremely important

1. Light intensity

The intensity of light is an important consideration in plant growth and lighting.

In the outdoors, the light intensity cannot be controlled too much, except for planting plants only in spring and summer (when the light is stronger). However, if you use a plant growth lamp indoors, you can adjust the light intensity by changing the distance between the lamp and the plant. That is to say, the closer the plant lamp is to the plant, the hotter the plant will be. So as not to burn the plants.

2. Spectrum of light

Light is a form of energy that exists and moves in the form of electromagnetic waves. The visible light we see is composed of electromagnetic radiation of a series of wavelengths.

Visible light is between 390-700 nm, and light of different wavelengths shows a certain color. Red has the longest wavelength and the least energy, while blue and purple light have more energy and shorter wavelengths.

Plants need various wavelengths in the spectrum to grow well, but the two wavelengths that have the greatest impact on plant health are red light and blue light.

Blue light has high energy and affects leaf growth and chlorophyll production. If your plant doesn’t get enough blue light, you may notice yellow stripes on the leaves.

Red light affects flowering and flowering. If your plants don’t get enough red light, they won’t bloom or bear fruit.

3. Day lighting length

Some plants will bloom only when they get enough sunlight. Some do not need too long sunshine, that is, some plants should not be exposed to light for more than 16 hours a day, because they really need a period of darkness to survive. Too much direct light can cause plants to burn, brown and die.