Greenhouse vegetable seedlings can suffer from root-related physiological diseases, often caused by improper management practices. Initially, the roots may show signs of rust, and in severe cases, the roots become rotten with no new roots forming. As a result, the seedlings turn yellow, wilt, and eventually die.
1. Maintain an appropriate temperature. The preparation of the bed soil should be done carefully to ensure good drainage and warmth. After sowing, it's essential to maintain sufficient soil temperature. During rainy days or periods of low light, take measures to keep the environment warm and insulated. In early spring, using electric hotbeds for seedling cultivation is highly recommended, as they help retain heat and promote healthy growth.
2. Control humidity effectively. When growing seedlings in greenhouses or shelters, avoid overwatering, especially when the seedlings are close together. Water only when necessary, and do not overdo it during dry spells. Keep the seedlings slightly dry, and if the soil becomes too dry, cover it with moist fine soil. This helps meet the plants' water needs while reducing air humidity. If the humidity is too high, you can sprinkle ash or ventilate the area during the hottest part of the day to lower moisture levels.
3. Ensure adequate lighting. Before starting seedling production, choose a location that receives plenty of sunlight. Good light exposure promotes strong growth, enhances disease resistance, and minimizes the risk of root-related issues in vegetable seedlings.
4. Apply well-decomposed farmyard manure. To grow healthy vegetable seedlings, it's important to enrich the soil with farmyard fertilizer, particularly hot composted manure. This improves soil fertility, strengthens the seedlings, and increases their resistance to diseases. It also helps raise the ground temperature, which reduces the chances of disease occurrence. The method involves mixing fully decomposed hot manure with the bed soil before planting. However, never use fresh manure, as it can burn the roots.
5. Ventilate regularly. Once the cotyledons have unfolded, choose a clear and warm day to open the cover for ventilation. Afterward, spread a thin layer of dry soil over the seedbed and re-cover it securely. This helps reduce soil moisture and also provides some warming benefits, promoting better seedling development.
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