How to prevent and cure the yellowing of tomato caused by poor coloring due to various reasons

The poor coloring of tomato is mainly caused by temperature, light, fertilization and so on.

Poor coloring and yellowing of tomatoes

One temperature. Tomato coloring is the decomposition of chlorophyll and the formation of lycopene and carotenoids. When the temperature is too high or too low, generally speaking, when the temperature is higher than 30 ℃ or lower than 10 ℃, it will affect the formation of lycopene. The tomato coloring was the best when the temperature was 18 ℃ ~ 26 ℃. When the daytime temperature was higher than 32 ℃, the tomato grew and matured faster, but affected the lycopene formation and thus affected the coloring. Especially in June summer, the temperature in the arch shed is high and lasts for a long time, which is the period of tomato expansion and color conversion, but the high temperature affects the formation of lycopene, resulting in the yellowing of tomato.

The second is the influence of light. The coloring of tomato also has a lot to do with light. If the planting density of tomato is too high, it will make tomato plants shade each other, so that the tomato can not get enough light, resulting in poor coloring of tomato, green shoulder fruit and uneven coloring.

The third is fertilization. Excessive application of nitrogen fertilizer and excessive vegetative growth make it difficult for tomatoes to color.

In the coloring period of tomato, especially in the red stage, when too much nitrogen fertilizer is applied, the chlorophyll will increase, which will delay or slow down the decomposition of chlorophyll, affect the formation of lycopene and carotene on tomato and affect the coloring of tomato. Too much nitrogen fertilizer aggravates the phenomenon of green shoulders in tomatoes. At the same time, if potash fertilizer is insufficient, tomatoes are also prone to yellow-green fruit shoulders.

Prevention and control measures:

1. When entering the high temperature period, it is necessary to increase the ventilation and light transmission of tomatoes and reduce the temperature in the greenhouse.

2. Tomato plants should keep row spacing during planting, and should not be too dense.

3. In the fruit setting period, reduce the application amount of nitrogen fertilizer, pay attention to the combined use of nitrogen, phosphorus and potassium fertilizer, and at the same time spray chitin + 0.2% potassium dihydrogen phosphate + calcium, boron and other micro-fertilizers on the leaves of tomato during the expansion period to promote the balanced growth of tomato.