Let’s speak about the vegetable harvest in greenhouse dependence of environmental factors. The following characteristics such as growth, development and as a result the productivity of the vegetable crops depend on the factors that are surrounding the plant other words it is the nature environment.
The dependence of harvests from environmental factors of the greenhouse
These factors are divided into 4 groups:
- Food factors are everything that may concern the ground, the physical properties of the soil, the content of the food elements in the ground and the moisture of the soil.
- The humidity, the air temperature and the light regime basically are the climatic factors.
- The biotic factors are the flora and the fauna.
- The anthropogenic factors are all the actions that the human does. It can be the use of fertilizers, the pesticides, the machines and all related actions that can increase the harvest.
There are three main indicators for assessing the response of the environment:
- The need or the exactingness. We can describe it as how much the plant organism needs this factor.
- The stability. It is the ability to remain under the influence of this factor for a long time and during a short time.
- The responsiveness is the rapidity and power of the reaction of the plant on different changes of the environment and the quantity of the given factor.
The thermal regime for the greenhouse vegetables
The optimum of the thermal regime is when the temperature is on the level when the plant can be developed most intensively. The minimum and maximum limits of the temperature are when the growth processes in plants stop.
The vegetable crops are divided into 5 groups according to the demand of air temperature:
- The first and the second group. The winter and frost resistant plants. Such type of vegetables can tolerate the significant drop in temperature even down to ten degrees Celsius below zero. The seeds of these cultures begin to germinate when the temperature going up to 1-2 degrees Celsius above zero. These vegetables are perennial such as sorrel, rhubarb, garlic, asparagus and others. Also you have to know that the root system of these vegetables has enough supply of nutrients and in case of frosts the supply can help the vegetable to survive.
- The third group. This group includes cold-resistant vegetables. Such type of plants does not tolerate prolonged frosts to up to seven degrees Celsius below zero. The germination of the seed begins when the temperature rises about 2-5 degrees Celsius above zero. The optimal temperature for the adult plants growth is around 18 degrees Celsius above zero. We can add to this group the following vegetables such as cabbage, lettuce leaf, radish, parsley, dill, spinach, onion and others.
- The fourth group. The heat-loving vegetables. The humidity of air for heat-loving crops should be at least on the level of 90% and the temperature of the air should be in the range of 22 – 29 degrees Celsius above zero. Such vegetables will die when the air temperature drops down to 3 degrees Celsius above zero. The group of heat-loving vegetables includes the following vegetables such as cucumber, tomato, pepper, eggplant and others.
- The fifth group is the heat resistant vegetables. The plants that belong to this group easily tolerate when the air temperature increase up to 36 – 40 degrees Celsius above zero. These vegetables do not tolerate when the temperature drops down to 10 – 15 degrees Celsius above zero. In order to receive an early crop of the vegetables from the heat-resistant group it is highly recommended to create favorable conditions for the cultivation of this group. You have to know that such kind of conditions is easy to make and control in the greenhouses. The heat resistant crops include vegetable beans, watermelon, melon and others.
- The fundamentals of vegetable greenhouse kits growing Part 1– The thermal regime in vegetable greenhouse
- The fundamentals of vegetable greenhouse kits growing Part 2 – The light and air-gas mode in vegetable greenhouse
- The fundamentals of vegetable greenhouse kits growing Part 3 – The watering regime in vegetable greenhouse
- The fundamentals of vegetable greenhouse kits growing Part 4 – The mode of nutrition of vegetable in greenhouse