If the ground temperature is stable above 10, you can sow. Planting time may be different in different areas. Sowing can be carried out according to local temperature conditions. Bamboo shoots are only planted in most northern areas (Henan, Hebei, Shandong, Shaanxi, etc.). In spring and autumn, spring stubble is the main crop, summer harvest and sowing in late spring and March. Lettuce can also be planted in plastic greenhouses in many places in the north, including spring and autumn (sowing in late September and harvesting in March and April), autumn extension (sowing in July and August and harvesting in February 10- 12) and overwintering stubble (sowing in early September and harvesting in the following year). Sowing can be done all year round in most parts of the south, including bare land, and winter lettuce can also be planted. High-altitude areas, such as Aba Prefecture, can be planted in March-June and harvested in July and August to fill the low season of vegetables in plain areas.

Downy mildew is a common disease in lettuce planting, mainly because the succulent stems of bamboo shoots are watered too much, the leaves become larger, and the ventilation between umbilical cords is not smooth, which leads to irregular spots on the leaves, and the back leaves turn brown and become a piece, and the germs extend to the stems, making the stems black. The main control methods of downy mildew are not only to control the humidity in the field, but also to use 40% cannon 1000 times or 50% morpholine oleate 1000 ~ 1500 times. I remember watching my mother grow lettuce when I was a child. My mother said that to plant lettuce, we should sow the bamboo shoots first, so that the bamboo shoots can germinate. But when sowing, we should not sow them too thinly, so that the bamboo shoots will not grow. The bamboo shoots can't be cold, and they are easy to cool and freeze. Please note that if the weather is cold, it is best to grow lettuce in Tucki. This will help the growth of bamboo shoots. The optimum germination temperature of lettuce seeds is 15 ~ 20. Now, when the temperature is above 30, the lettuce seeds will not germinate directly, and the seeds must be refrigerated at low temperature to accelerate germination.

Two days before sowing and seedling raising, the seeds are soaked in clear water for about one hour, and rubbed several times during the soaking process to remove the oily protective layer on the outer layer of the seeds. Then, the seeds are wrapped with gauze or screen, and stored in the refrigerator or near Old Jing Quan for 48 hours. When the seeds reach 80%, you can sow the seedlings. Earthworms belong to dilute temperature crops, which are cold-resistant and heat-resistant. It's easy to fall during high temperature. How to prevent this situation is related to output and commodities.

The first method is to make a sunshade film in the vegetable garden to prevent the sun from shining for a long time, and at the same time, it can achieve the effect of cooling down, which is conducive to normal growth and slow down the harvest in advance. The second method is to spray 500 ~ 800/ L green growth hormone once a week for two weeks to increase the yield and prevent bolting. In addition, the same effect can be achieved by spraying gibberellin solution with a ratio of 1000 times almost one week before the heart leaves at the top of lettuce contact with the outer leaves.