When to sow Chinese cabbage? Start of Autumn is the suitable sowing time
August 7 is the Start of Autumn solar term, heralding that the hot summer is about to pass and autumn is about to arrive. After Start of Autumn, each rain brings a spell of cool weather, hence the farming proverb "one autumn rain, one spell of cold." The weather at Start of Autumn is still within the three fu periods, with ample sunlight, heat and frequent rain, so vegetable production should focus on sowing autumn crops, raising seedlings and field management.
?Sowing of autumn Chinese cabbage and radish
In plain areas such as Daxing, Shunyi and Tongzhou, the suitable sowing period for Chinese cabbage is August 3-8, and for Xinlimei radish (watermelon radish) it is August 5-12; in high-altitude mountainous areas such as Miyun, Yanqing and Huairou, the sowing period should be 5-7 days earlier than in the plains. Apply decomposed, finely crushed organic fertilizer as base fertilizer; for Chinese cabbage apply 5000 kg per mu, or 3000 kg of commercial organic fertilizer; for Xinlimei radish apply 3000 kg-4000 kg per mu, or 2000 kg-3000 kg of commercial organic fertilizer. Improve the quality of land preparation, make high beds about 15 cm above the ground for sowing, sow evenly and with a reasonable density. For Chinese cabbage, row spacing 60 cm, plant spacing 33-35 cm, 2400-3000 plants per mu. For Xinlimei radish, row spacing 55 cm, plant spacing 20-22 cm, 5500-6000 plants per mu. After sowing, if high-temperature weather occurs, water between the rows in time to cool down. To achieve the goal of complete and strong seedlings of Chinese cabbage free from viral disease, follow "three waterings for complete seedlings, five waterings to set the plants."
Seedling raising and seedling management of autumn crops
For autumn-winter crops such as tomato, chili pepper, sweet pepper and eggplant grown in solar greenhouses with good insulation performance, the suitable sowing and seedling-raising period is still ongoing; choose excellent varieties tolerant to low temperature and weak light. Choosing a good seedling-raising site is very important: carry it out in a greenhouse or dedicated seedling greenhouse with high, dry terrain, capable of both irrigation and drainage, and good ventilation, with insect-proof nets sealing the air vents and doorways tightly. At noon, cover the greenhouse roof with shade nets to cool down; if conditions permit, install external shading and micro-sprinkler cooling facilities. To prevent waterlogging from rain, dredge drainage ditches around the area. Also do a good job of seed disinfection and treatment, focusing on the prevention and control of tomato yellow leaf curl virus. Celery is at a critical period of seedling management; at this time of high temperature and frequent rain, seedlings are prone to spindly growth and damage from pests and diseases, so do a good job of cooling, shading, rain protection, thinning and pest and disease control, and raise age-appropriate strong seedlings under unfavorable climate conditions.
?Field planting of autumn open-field cauliflower
Autumn open-field crops such as cauliflower, cabbage, lettuce and celtuce can still be planted. Apply sufficient base fertilizer: 3000 kg of decomposed, finely crushed organic fertilizer per mu, or more than 2000 kg of commercial organic fertilizer. Prepare the land finely, make flat beds 1.3 m wide and 8-10 m long; for heavy clay soil, make high beds, and do a good job of drainage and waterlogging prevention. Choose a sunny afternoon for planting, do not plant too deep, and cover soil level with or slightly higher than the seedling block. For cauliflower, green cauliflower and loose-curd cauliflower, plant 2500-3000 plants per mu, generally with an average row spacing of 60-65 cm and plant spacing of 40-50 cm. For cabbage and head lettuce, about 4000 plants per mu, generally with an average row spacing of 40-45 cm and plant spacing of 30-35 cm. For celtuce, 6000-9000 plants per mu, with an average row spacing of 20-25 cm and plant spacing of 18-20 cm. After planting, water thoroughly in time.
????Sowing of heat-tolerant leafy vegetables
Heat-tolerant leafy vegetables such as amaranth, water spinach, Malabar spinach, spinach, bok choy and cilantro can still be sown in successive batches; decide the planting area of each batch according to expected sales.
Generally they can be harvested and marketed 30-50 days after emergence. Prepare the land finely, make flat beds 1.3 m wide and 8-10 m long, adopt the drilling method, sow evenly, and cover soil to an appropriate depth. Also do a good job of drainage and waterlogging prevention.
?Management of overwintering summer crops and autumn crops in greenhouses
Over-summer crops such as loofah, bitter gourd, chili pepper and eggplant, and summer-autumn tomato, are at the flowering and fruiting stage, while autumn-planted tomato and cucumber are at the seedling and flowering stage. Field management should be strengthened to promote robust plant growth without excessive vegetative growth.
◆Do a good job of shading and cooling. After Start of Autumn the temperature is still relatively high; on sunny days from 11:00 to 15:00, cover the greenhouse roof with shade nets with a shading rate of 60%-70%; you can also lower the greenhouse temperature by watering between the rows or by micro-sprinkler irrigation at noon on sunny days.
◆Strengthen plant training. Timely train the vines, prune and remove side shoots, and promptly remove lower old leaves, yellow leaves and diseased leaves to facilitate ventilation and light penetration and reduce nutrient consumption.
◆Do a good job of fruit management. Melon and fruit vegetables do not set fruit well when the greenhouse temperature is too high. For bitter gourd and pumpkin, use artificial pollination in the morning; for eggplant and tomato, use bumblebee-assisted pollination or spraying with "Fengchanji No. 2" and "Guomeining" to increase the fruit-setting rate. After young fruits set, promptly thin out excess fruits and those too large or too small; deformed fruits should also be removed early.
◆Scientific topdressing and watering. According to weather conditions, soil conditions and plant growth, water and topdress in a timely manner to promote plants that neither grow excessively nor age prematurely and bear more fruits with a high marketable rate. Promote the integrated water-fertilizer method and topdress with fertilizer with a reasonable nitrogen-phosphorus-potassium ratio. Spray foliage fertilizer once every 7-10 days to quickly supplement nutrients.
◆Pest and disease control. Diseases such as viral disease and powdery mildew and pests such as whitefly, red spider mite and broad mite are common. In particular, focus on preventing tomato yellow leaf curl virus and control infection at the seedling stage. Give priority to using yellow and blue sticky traps to trap and kill adult pests such as whitefly, aphid, thrips and leafminer; cover air vents and doorways with insect-proof nets to block pests from entering the greenhouse; at the early stage of occurrence, use biological pesticides or low-toxicity, high-efficiency pesticides. Strictly observe the regulation of waiting through the safety interval after applying pesticides before harvesting to ensure product safety.
◆Timely harvesting. After Start of Autumn, the temperature difference between day and night gradually increases, crops grow fast, and mature fruits should be harvested in time. The best harvesting time is early morning on sunny days, when product quality is good. If the product cannot be sold immediately after harvest, store it in a dark, low-temperature environment.
????Welsh onion should be protected from pests such as thrips
Welsh onion is at the stage of vigorous plant growth. Do a good job of hilling and inter-row cultivation and loosening of the soil, water and topdress in a timely manner, water promptly when the soil is dry, and combine hilling with topdressing organic fertilizer, applying 300 kg of bio-organic fertilizer per mu each time, or 20 kg of nitrogen-phosphorus-potassium compound fertilizer. For plots planted early, hill up in several sessions, each time hilling up to the junction of the leaf blade and leaf sheath, without burying the heart leaves. Promptly pull out weeds between the rows and at the field edges. This period is when pests such as thrips cause the most rampant damage; control them promptly by spraying with spinetoram 1500-fold dilution. Note that it should be sprayed on the young tender parts of the plant and on the ground, because the leaf surface of Welsh onion has a waxy layer, and 80% of the pesticide sprayed on it will slide off, affecting the control effect; when preparing the pesticide, add pesticide adjuvants such as "Xiaokangye" or "organosilicon" to ensure the control effect.