Published: Apr 21, 2022
Control of environmental factors that affect plant growth in greenhouses
If you are thinking about growing in a greenhouse, or are already doing so, you should know that if you do not properly control the environmental factors that affect plant growth (light, temperature, nutrients, water and humidity) you may risk losing your precious harvest.
Planting in greenhouses can be a real challenge for any beginner, since, being an enclosed space - although not entirely - the growing conditions are completely different.
Usually, when we plant in greenhouses, we seek to control those environmental factors that affect plant growth in open spaces. But what are the that factors? How do I know which one affects my crop? What do I have to do to make my harvest successful? Well, here we will tell you.
Discover specifically: the five (5) environmental factors that affect plant growth, how to heat and control the environment inside greenhouses, and some tips for growing Cannabis plants.
5 Environmental Factors That Affect Plant Growth
There are five (5) environmental factors that affect plant growth considerably, both in open and enclosed spaces; farmers are looking for ways to control them, so that their crops can meet their full cycle.
When we sow outdoors, the plants are exposed to different climatic changes, this allows the elements necessary for the correct growth of the plants to vary, either increasing or decreasing. These fluctuations can adversely affect the natural cycle of your crop, especially if your planting corresponds to specific requirements.
Being an open space, the grower is tied hands to control those unevenness that harm their planting, therefore, to avoid losses of money and work, they see the need to go to closed spaces to cultivate successfully.
Greenhouses are the answer to this situation. So it has become more recurrent the cultivation in these spaces, especially, of those plants susceptible to environmental changes. As in the case of tomato, lettuce, beets, eggplant, spinach, cucumber, melon radish, potato, watermelon, etc.; some ornamental plants such as chrysanthemum, poppy, Christmas cactus, etc.; and other medicinal plants such as cannabis.
Let's look, in detail, at these 5 environmental factors that affect plant growth:
The water supply is a fundamental and decisive factor for the existence of plants. Well, this factor must accompany it from germination to harvest. Water, in some cases, is so important and necessary that it allows a seed to germinate or a plant to live, even if there is no soil.
On the other hand, there are also those species that need very little water to live, and that if there is an increase in the supply can drown the plant until it withers.
When planting in open spaces, the main water supply is given through rain, so if we are in winter the supply will be greater, or on the contrary, it will be scarce if we are in summer. This forces producers to plant in a limited way, using the characteristics of the crops.
What that tells us is that water can affect a plant's growth, either positively or negatively. Therefore, it is necessary to know the demands of the plants that will be grown; that way your supply will be adequate and you can stimulate the healthy growth of them.
Light is another of the environmental factors that affect plant growth, and that, like water, is necessary for their germination, growth and flowering.
By planting outside, plants absorb light energy from the sun, receiving a full spectrum. Whereas when growing indoors, whether indoors or in greenhouses, you need an artificial light source that offers a spectrum much like natural light, such as that provided by LED lights.
For the correct development of crops, it is important to consider the quantity (intensity or power), quality (type of wavelength) and duration (hours of exposure) of light. Well, with them, photosynthetic processes, growth and flowering will be facilitated.
The absence of light can cause the plant to grow without uniformity, have an opaque color and do not comply with its normal processes in the given time.
Excess light, on the other hand, can burn part of its structure and alter the flowering time. While the poor quality of light, especially in the cultivation of enclosed spaces, will modify its proper growth and development.
Also, in order to control this factor, it is essential to know the requirements of your crop.
Temperature is the next incident factor in plant growth. This, in particular, is a factor that is impossible to control when it comes to crops in open spaces.
Usually, plants can grow properly at a temperature ranging from 15° C to 40° C. But due to seasonal change and the normal climate of some countries, colder or hotter spaces are found, affecting crop growth.
The high temperatures favor the low absorption of water, drying out the soils and dehydrating the plant itself. And very low temperatures could cool the cells in such a way that it will prevent the normal transit of fluids and components.
When temperature negatively affects plants, it can cause considerable damage to their existence, which is why it is one of the environmental factors that are sought to be controlled in the use of greenhouses, especially through thermometers.
Humidity is the amount of water in the air. And although it is one of the least popular factors, it affects the process of growth, perspiration, absorption and pollination. In addition, an environment with excess humidity tends to favor the appearance and spread of diseases and pests. It also contributes to the malformation of plant structures.
Although the percentage of humidity is determined by the type of crop, it must be found between 50% and 90%.
In the case of greenhouses, hygrometers are used to monitor the level of humidity in the space and take the necessary measures in the event of any fluctuation.
Nutrition is the last factor we will analyze, and not because it is the one that affects plants the least, but because it is affected, in turn, by the other factors.
When the levels of water, light, temperature and humidity are altered, the nutrients that make up the environment where the plant develops are modified, affecting its absorption and subsequently its growth.
For plants to grow properly you need: carbon, hydrogen, oxygen, nitrogen, calcium, potassium, magnesium, sulfur and phosphorus. And they are found in water, air and soil; therefore, any factor that modifies them can generate nutrient deficiencies.
Air conditioning and climate control inside the greenhouses
Thanks to the air conditioning and climate control inside the greenhouses you can:
- Isolate crops from external conditions.
- Control the environment to cultivate.
With this, it has been possible to regulate the environmental factors that affect plant growth, managing them in a positive way so that they contribute to the good growth and development of our crops.
The most common ways to control environmental factors within greenhouses are:
The water supply in greenhouses is due to irrigation systems. Which comes to efficiently supplant rain.
They can place it aerially or at the level of the crop, and it is activated according to the requirements of the plantation.
With the implementation of irrigation systems you can grow any plant throughout the year, without having major concerns.
Although the light in greenhouses is not totally isolated, it must be complemented with grow lights, and these can be: CMH, fluorescent, HPS, MH or LED.
The function of these lights will fall on the exposure of the wavelengths necessary to stimulate the growth of plants according to their stage of development.
The ideal is to place lights that can offer a full spectrum of light (the most similar to that of sunlight) so that the plants receive the quantity and quality necessary for their correct growth.
In order to isolate the temperature of the greenhouse from the outside, a total secrecy of the space must be achieved and create (with heating or cooling systems) the ideal temperature for the type of crop.
Usually, in places with cold weather the heating system is used to counteract low temperatures. And in hot places, cooling systems are employed, either with fans or air conditioning units.
Humidity levels are stabilized with the measures taken to control water and temperature. But, if you consider that it is not enough, you can use humidifiers with a dehumidifier option, to increase or decrease the percentage of humidity.
It is important that you remember that, humidifiers, you must acquire them according to the size of your greenhouse or higher, because if you select one of lower capacity you will not get the results you want.
Once the environment corresponding to your crop is assembled, the amounts of nutrients that your plants need should be normalized.
As an addition, you could place fertilizers to reinforce any deficit in the soil. Just make sure you dissolve and add them correctly so that they can be synthesized more easily and not spoil the leaves.
Tips to control the environmental factors that affect the growth of Cannabis plants
If you are thinking of growing Cannabis, medicinally or recreationally, you should know these tips that will help you control the environmental factors that affect plant growth:
- Cannabis plants during their early stages of vegetative growth require: 50% to 70% humidity; 18 hours of light and 6 hours of darkness (light must contain the lengths of the PAR range, ultraviolet and far red light); and a temperature ranging between 20ºC and 25ºC.
- In the pre-flowering stage: A humidity between 40% and 50% is needed; greater exposure to red light; and a temperature of 20ºC to 28ºC.
- In its last stage it demands: more nutrients (water with pH 6.2) and a temperature of 24°C to 26°C.
- In addition to creating the necessary conditions for your cannabis plants to grow properly, it is necessary that you protect them from pests and diseases, which can affect both their growth and their quality.
Currently, there are many ways and equipment to control environmental factors and external agents; it must be properly documented to achieve healthy plants with optimal growth within a controlled environment in which they have most of the elements they could find in a natural environment.