How to grow vegetable seedlings during high-temperature periods? Remember these five steps

During high-temperature periods, direct-sown vegetables grow poorly and are prone to pests and diseases, so seedling cultivation is necessary. Vegetables grown as seedlings in summer and autumn mainly include cauliflower, cabbage, summer Chinese cabbage, lettuce, and late-autumn peppers, eggplants, and tomatoes. Summer and autumn vegetable seedling cultivation must achieve the "six preventions," namely preventing strong light, preventing rain damage, preventing drought, preventing high temperatures, preventing pests, and preventing root damage.

?Determining the sowing period

The sowing period for vegetable seedlings during high-temperature periods should be determined by comprehensively considering the planting method, climatic characteristics, vegetable type, and the selected variety. Because of the high temperatures, seedlings grow and develop quickly, and the seedling period is greatly shortened compared with autumn and winter vegetable seedling cultivation. Cucurbit vegetables need only about 20 days, solanaceous fruit vegetables about 30 days, and cabbage-type vegetables have a seedling age of about 25 days. Seedling facilities

For vegetable seedling cultivation during high-temperature periods, in addition to seedbeds, shade and rain protection facilities must be used. Using the frames of large tunnels, medium tunnels, or small arch tunnels and covering them with shade netting, insect-proof netting, old greenhouse film, etc., can effectively reduce the adverse effects of high temperatures and heavy rain on vegetable seedling cultivation. Plot selection

The seedling plot should be dry and level, with good soil permeability and water retention, and capable of both irrigation and drainage. Avoid growing seedlings on continuous cropping land or plots where the same crop of vegetables was previously grown, to prevent soil-borne disease damage, and avoid growing seedlings on plots with severe underground pest problems.

Choose fertile garden soil that has not grown vegetables of the same family for many consecutive years and fully decomposed high-quality barnyard manure as the seedbed soil raw materials, mixed at a soil-to-manure ratio of 2:1. For each cubic meter of seedbed soil, add 60 g of 90% trichlorfon crystals and 80 g of 75% thiram wettable powder. Mix the soil, manure, and chemicals thoroughly, then sieve and set aside for use. To prevent root damage during transplanting, nutritional pots can be used for seedling cultivation. Seed treatment

Hot water seed soaking. For example, put seeds of cucurbit and solanaceous fruit vegetables into 50-55°C warm water and stir to scald the seeds. When the water temperature drops to 30°C, soak the seeds for 6-8 hours, then soak them in a 500-fold solution of 50% carbendazim wettable powder for 20 minutes, wash clean with clear water, and then place them under 30°C conditions to promote germination.

Liquor seed soaking. Use seeds, liquor, and water at a weight ratio of 1:0.5:0.5. First mix the liquor and water well, then put the seeds in and soak for 10 minutes. After removing them, wash clean with clear water.

Potassium permanganate solution seed soaking. First soak the seeds in 50°C hot water for 25 minutes, then soak them in a 1% potassium permanganate solution for 15 minutes. Copper sulfate solution seed soaking. First soak the seeds in clear water for 10-12 minutes, then soak them in a 1% copper sulfate solution for 5 minutes. After taking them out, wash clean with clear water. This can prevent bacterial diseases. Carbendazim seed soaking. Soak in cold water for 3-4 hours, then transfer to a 500-fold solution of 50% carbendazim wettable powder and soak for 1 hour. Wash clean with clear water. This can kill or attenuate pepper viruses.

Chemical seed dressing. Put the seeds into a clean container, then add chemicals such as thiram and carbendazim at 0.3% of the seed weight, so that the chemicals evenly adhere to the seed surface. This can kill many kinds of pathogens.

?Do a good job of the "six preventions"

Use the frames of large tunnels, medium tunnels, or small arch tunnels and cover them with shade netting or old greenhouse film (which can be coated with mud slurry) to provide shade, prevent high temperatures, prevent strong light, and prevent rain damage. If there is no old greenhouse film on the seedbed, cover it promptly with greenhouse film before rain.

Water thoroughly before sowing; 2-3 irrigations can be given before sowing. After sowing, cover with straw mats to keep the seedbed moist. If water is lacking during the seedling stage, water lightly in the morning and evening to replenish moisture and prevent viral diseases caused by high temperatures and drought. Use insect-proof netting coverage to prevent damage by pests such as aphids, whiteflies, and leafminers.

It is recommended to use nutritional pots or paper cups for seedling cultivation to reduce damage to the seedling root system during transplanting and reduce the occurrence of soil-borne diseases caused by root damage.