6 causes of uneven seedling emergence
In the process of vegetable seedling rearing, there often appear the phenomenon of uneven seedlings. Uneven seedling emergence in the seedling bed brings a lot of inconvenience to the seedling management, but also affects the seedling growth rate because of the removal of old young seedlings, so why the phenomenon of uneven seedling emergence? The main reasons are as follows.
1. Using seeds that are not ripe enough
Normal mature seeds have more keratin structures in the endosperm, while immature seeds have silty endosperm, and the keratin structure absorbs less water than the silty endosperm. Therefore, normal mature seeds only need to absorb less water to germinate, and seeds with lower maturity need a relatively longer time to germinate.
2. The seeds are dormant
Seeds have a certain period of dormancy, which can not germinate even if the condition of suitable growth is reached. Sowing seeds that do not break the dormancy period will lead to uneven emergence or even no germination.
3. Use aged seeds
As time goes by, the vitality of the seed gradually declines, the germination rate also decreases, and it will affect the germination time.
4. Damaged or improperly stored seeds
In the process of seed processing, due to mechanical damage caused by seed embryos, endosperm damage, as well as improper storage after purchase, such as humidity, high temperature, poor ventilation environment, will lead to uneven seedlings.
Sowing depth also has a great influence on seed emergence. Different sowing depth will lead to inconsistent seedling emergence speed.
Sowing too deeply can lead to slow or even no emergence of seedlings, but also excessive consumption of nutrients resulting in weak seedlings.
The sowing depth of tomato and pepper is about 10mm, the sowing depth of lettuce is about 5 ~ 10mm, and the sowing depth of pellet and raw vegetable seeds should be within 5mm because of the coating problem.
Artificial irrigation is prone to uneven watering, which will lead to slow seedling emergence in places with insufficient irrigation. After seedling emergence, the substrate humidity is low in places with less irrigation, and the seedlings grow slowly. In places with high substrate humidity, the seedlings may also emerge slowly, or even rot.
The air around the seedbed is large, the light is sufficient, the matrix is drying faster than the middle, especially when the sun is strong, we should pay more attention to the supplement of fertilizer.
Too much irrigation water at seedling stage can lead to retting of the roots, poor root development, resulting in smaller seedlings and even death.
The less irrigation, the lower the water content of substrate, the slower the growth of seedlings.
Control the growth height of seedlings by water control, it is easy to produce aging seedlings due to excessive water control, resulting in uneven height of seedlings.
The correct way to control the height of seedlings is to reduce the air humidity, reduce the temperature, and strengthen ventilation.
The lack of fertilizer supply at seedling stage will lead to the growth of seedlings, yellow and white leaves, emaciated, and the lack of fertilizer will also lead to the uneven height of seedlings.
Drug damage is generally caused by excessive concentration of pesticides, such as leaf wilt, necrosis, distortion, etc., less seriously affected seedlings grow slowly and uneven, serious ones will stop growing, or even disappear.
Too much fertilizer after the substrate nutrient concentration is too high, will lead to seedling cells in the water to the substrate reverse osmosis, so that the seedling wilting, leaf edge dry yellow, serious lead to death of seedlings.