What are the reasons why head lettuce does not form heads?

Head lettuce is unlike the loose-leaf type of lettuce; it is a lettuce that forms a head and folds its heart during growth. It is also very popular in the market, but during cultivation it is sometimes found not to fold its heart. This directly affects its market quality. So today we will discuss the reasons why head lettuce does not form heads, and how to solve this problem.

1. Reasons

It may be due to the variety; choose a cultivar according to the local environmental conditions. For example, if the local head-forming period falls in a high-temperature stage, you can choose a variety with higher heat tolerance. Single-type fertilization causes failure to form heads: excessive nitrogen fertilizer, lack of phosphorus and potassium fertilizer, or lack of trace-element fertilizer. Too high a temperature: the temperature during head formation must not exceed 25 degrees, which easily causes damage. The head-forming period needs a large amount of water, and insufficient watering is also a reason. Pests and diseases also have an effect, and are generally easy to spot.

2. Fertilization

For one mu of lettuce, use about three thousand jin of decomposed organic fertilizer and one hundred jin of compound fertilizer; these are the base fertilizer, or bottom fertilizer. For topdressing, about two to three weeks after transplanting and seedling recovery, apply another forty jin of compound fertilizer. One month after transplanting, apply another thirty jin or twenty jin of compound fertilizer. After that, no fertilizer is needed.

3. Temperature and humidity

Lettuce likes a cool climate, so planting in spring or autumn is better. For late-spring planting, do not let the head-forming period fall in summer; it cannot be planted in midsummer, otherwise head formation very easily fails, and it easily rots when it rains. Normally keep moisture balanced, keep it moist, and maintain 65% humidity. During the proper head-forming period, you can water more. After the head has formed, water must be controlled; too much water easily causes rot.

4. Pest and disease control

Planting in protected facilities makes disease more likely, but open-field disease is also not negligible. Common diseases affecting head formation are soft rot, viral disease, and tipburn. The pests affecting head formation are aphids and whiteflies. Disinfect seeds and soil, and sun the ground. When disease is found, spray promptly to control its spread. Use relevant agents for control. You can also cover with silver-gray film to repel them.

Head lettuce is a lettuce variety with relatively good economic returns. There are many reasons affecting the failure to form heads during cultivation; judge carefully before deciding on countermeasures.