How to harden off early spring vegetables? Detailed explanation of methods and precautions
Although the pandemic situation is severe, the vegetable basket still cannot be cut off. Now many early spring vegetables have already begun to be transplanted one after another, but during hardening off, seedlings are very likely to suffer cold damage and disease damage after transplanting. So how should early spring vegetables be hardened off? What should be noted during hardening off? Let's learn about it together with the editor.
1. Hardening off time
The hardening off time is generally controlled to about one week, usually carried out 7-10 days before transplanting. In the first 5-7 days, temperature control, water control and appropriate ventilation are generally carried out; in the last 3-4 days, continue lowering the temperature, controlling water and providing full ventilation, so as to promote the seedlings to fully adapt to the environment after transplanting. Temperature reduction should be carried out gradually, water control should also be appropriate, and ventilation should go from small to large. In addition, the low-temperature hardening off time should be neither too long nor too short. If the hardening off time is too short, it cannot play the role of strengthening the seedlings and making the plants healthy. But if the hardening off time is too long, it is very easy to form aged seedlings, which is not conducive to seedling recovery and is also very prone to premature aging, which is extremely unfavorable for later growth.
2. Hardening off methods
10 days before transplanting, gradually lower the temperature of the seedbed. During the day, appropriately increase the ventilation amount and extend the ventilation time; in the evening, cover the shed appropriately later, and leave an appropriate gap for slow temperature reduction. The daytime temperature can be slightly higher, while the nighttime temperature can be as low as about 12°C. Under the condition of ensuring that the seedlings are not frozen, lower the nighttime temperature as much as possible. During low-temperature hardening off, the seedlings grow slowly, so water should be appropriately controlled. Also, before hardening off, potassium dihydrogen phosphate can be sprayed to improve the stress resistance of the seedlings. In autumn hardening off, as long as the seedlings do not wilt at noon, watering is generally not needed. If there is wilting, an appropriate amount of light watering or spraying can be done so that the seedlings can recover normal growth.
3. Precautions for hardening off
During hardening off, always pay attention to the weather forecast. When temperature drops and cold waves occur, cover the seedling shed appropriately in advance at night to prevent the seedlings from freezing. During hardening off, the low temperature should be reasonable. If the temperature is too low, it will cause problems such as renewed yellowing of leaves, thin stems and stiff seedlings. During hardening off, those diseased, weak and incompletely developed seedlings should be removed in time, and the spacing between seedlings should be appropriately increased to improve air permeability. After transplanting and seedling recovery, appropriately widen the day-night temperature difference for seedling training. This can promote the seedlings to become further stronger.
The above is an introduction to the methods and precautions for hardening off early spring vegetables. I hope it can help you. To learn more related knowledge, please follow us.