Why Tomatoes Don't Grow and Turn Yellow, and How to Fix It

Mr. Gao of Gedaodian Township, Wuzhi County, Jiaozuo, grows 10 mu of greenhouse tomatoes. Just half a month after planting, he noticed yellowing and asked what was going on. So what causes tomatoes to stop growing and turn yellow? What should be done?

According to research by tomato cultivation expert teacher Ying Fangqing, there are several factors behind yellowing leaves:

1. Climatic factors. Many cloudy days, slow seedling recovery, and stored substances inside the leaves are excessively consumed.

2. Fertilizer damage. In production, organic fertilizer that is not well decomposed and not thoroughly rotted produces heat damage and harmful gases (ammonia, hydrogen sulfide, nitric oxide).

3. Bacterial diseases. Tomato bacterial canker, which occurs on the leaves, starting at the leaf margins and leaf tips.

4. Fungal diseases.

5. Nutrient deficiency, especially magnesium deficiency, when yellow patches appear on the leaves. Yellow patches appearing on the lower part indicate magnesium deficiency; those appearing on the upper young leaves may be a virus disease.

How should this be prevented and controlled?

1. For fertilizer damage, pay attention to watering and ventilating to release gas. Harmful gases dissolve in water, which can reduce heat damage.

2. For diseases, spray chemical agents in a targeted way. For bacterial diseases, copper-based preparations such as Kocide are commonly used in production; antibiotics such as zhongshengmycin and streptomycin sulfate can also be used.

3. Magnesium deficiency has been very common on tomatoes in recent years, and magnesium sulfate can be sprayed on the leaves.