Autumn Lettuce planting and sowing period is in the hot season, small temperature difference between day and night, night temperature is high, strong breathing, easy to grow, and at the same time due to high temperature and long days easy to make the asparagus flower bud rapid differentiation and convulsions, so the cultivation of strong seedlings and prevent unripened Brewing is the key to the cultivation of autumn lettuce.
Selection
Choose a variety that is resistant to heat and convulsions. Asparagus officinalis seedlings are in favor of convulsions under high temperature and long-day conditions, so we must choose to respond to high temperature and long days, the sharp-leaf type of late-maturing varieties, such as purple skin incense, willow lettuce, spring and so on.
Seeding
Autumn sowing from sowing to harvest takes three months, suitable for stem and leaf growth in the appropriate temperature period in the ten days after the temperature dropped to 21 degrees Celsius after about 60 days, so the seedling period should be arranged in the ten-day average temperature dropped to 21 °C ~ 22 The previous month at °C is safer. Although the sowing date is too late, it is not easy to convulsive, but due to the short growing period, the yield is reduced.
Nursery clearance
Summer seeding due to high temperature seed germination difficulties, sowing must be low temperature soaking germination, soaking in cold water after a day and night soaked in 15 °C ~ 20 °C temperature, 3 to 4 days after budding, in the afternoon when the temperature is low seeding. After sowing, it was covered with wheat straw, straw, etc. to achieve the purpose of moisturizing, cooling and preventing rain. It can also be mixed with Chinese cabbage. The emergence of Chinese cabbage can be used to shade the lettuce, and the cabbage can be gradually removed after the seedlings begin to grow.
There are wet sowing and dry sowing methods. When the seedlings are topped with wet sowing method, they are sprinkled with water once, and they are discharged after 1 to 2 days. Dry broadcasts must be sprayed regularly to keep the soil moist and reduce ground temperature. Note that water must be applied sooner or later. Gradually withdraw the cover after the emergence, to strengthen the exercise of the seedlings, after the first pouring water to reduce seedbed temperature to prevent seedlings from sunburn, and later still have to pour small water, keep the soil moist, timely pouring water after the rain to reduce the temperature to prevent seedlings. Timely weeding, insect control, and seedlings, and 3 to 4 true leaves were treated with a quick-acting nitrogen fertilizer.
Management
Seedling age 25 to 30 days, there are 4 to 5 true leaves when planting, it is best to plant soil in the afternoon with a view to ease the seedlings. Before the planting, the base fertilizer must be applied. To prevent the growth of the autumn lettuce, the requirements of water and fertilizer must be met as far as possible so that the leaf area can be expanded rapidly. After the planting, the soil was poured and poured gently until the seedlings were reduced. After the seedlings were grown slowly, a quick-acting nitrogen fertilizer was applied. Thereafter, watering was appropriately reduced and a deep cultivator was used to extend the root system. The second round of topdressing was performed during the planting period to accelerate the occurrence of leaves and the expansion of leaf area. Immediately before the ridge closure, the stems begin to expand for the third time. In addition to the application of available nitrogen fertilizers, potassium fertilizers are added to promote stem hypertrophy.
Adjustment
Plant growth regulators are used to inhibit immature convulsions. When the stems of the asparagus doublings begin to grow in size, they can be sprayed with chlormidine or chlorophyllin for 2 or 3 times, which can effectively inhibit twitching and increase stem weight.
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