There is more to summer celery planting time and methods than meets the eye, and getting it right is key
Summer celery seedling raising coincides with high temperature, high humidity and strong light, and under such weather conditions celery seed germination is difficult, so summer celery planting has many particulars. So what are the summer celery planting time and methods?
1. Summer celery planting time
Celery likes cool conditions and is relatively cold-tolerant; it is a semi-hardy vegetable. The seeds begin to germinate at 4°C, and the optimum germination temperature is 15-20°C. Above 25°C or below 15°C, the germination rate decreases or the germination time is prolonged. However, the seedlings can endure low temperatures of -4 to -5°C, and mature plants can withstand low temperatures of -7 to -8°C, but their quality declines after freezing. The optimum growing temperature for celery is 20-22°C during the day and 13-18°C at night. The soil temperature should preferably be 15-23°C; generally, it must stay above 5°C at night to ensure normal growth of celery.
For summer-planted celery, seedlings should be raised in the open field after the last frost in spring, transplanted in early June to July, and harvested and marketed from August to September. In the hot and rainy season, summer celery grows poorly, many seedlings die, yields are low, and the planting area is not large.
2. Summer celery planting methods
1. Sowing and seedling raising
(1) Seedbed selection
Celery likes a cool climate, so its seedbed should be chosen on a site with loose, thick, fertile soil, convenient drainage and irrigation, and relatively shady conditions. Apply 100 kg of lime per mu, dig it deeply into the soil, and burn and sun it until it turns white.
(2) Land preparation and bed making
Make beds about 1 m wide, apply 2,000 kg of human and animal manure per mu, and after drying, break up and level the bed surface. During soil preparation, add 1 kg of carbofuran to eliminate earthworms.
(3) Seed soaking and germination
Put the seeds in a cloth bag, tie one end of a long rope around it, and lower it into well water to soak for 48 hours. Then suspend the seeds in the well about 0.5 m above the water surface for germination. They will germinate in 3-4 days. When more than 80% of the seeds have germinated, they can be sown. If there is no well, germination can be carried out in an earth cave or in the refrigerator compartment of a fridge, that is, after soaking in cool water for 48 hours, take them out and dry the surface moisture, then wrap them well and put them in the refrigerator compartment for 24 hours.
(4) Sowing rate
One mu of field requires 500 g of seed, and 1 mu of seedbed can sow 2 kg of celery seed. When sowing, mix the germinated seeds with old rice husk ash or dry fine soil and broadcast evenly. After sowing, pat the bed surface lightly and sprinkle water with a watering can. In summer, pay attention to covering with a shade net to lower the temperature and prevent rain.
2. Seedbed management
Generally, in good weather, water once every evening; in hot, dry weather, water once in the morning and once in the evening every day. After the seedlings emerge fully, begin topdressing, applying light manure water once every 5-7 days, and pay attention to controlling aphids.
3. Soil preparation and fertilization
For celery cultivation, choose sandy loam rich in organic matter and with strong water and fertilizer retention. Broadcast 150 kg of quicklime per mu, dig it deeply into the soil, burn and sun it until it turns white, and make bed soil about 1.67 m wide. Apply 100 kg of rapeseed cake, 200 kg of human and animal manure, 20 kg of urea, 40-50 kg of phosphate fertilizer, and 10-15 kg of potash fertilizer per mu, turn them shallowly into the soil, level and refine the soil, and leave it idle for 4-5 days before transplanting.
4. Transplanting
When the seedling age reaches 50-60 days and the seedlings are 12-15 cm tall, they can be pulled and transplanted. Spray an insecticide once before pulling the seedlings (such as deltamethrin, etc.), and water 3-4 hours before pulling the seedlings so that the bed soil is fully moist. The transplanting row spacing is 16-26 cm, the cluster spacing is about 1 cm, with 4-5 plants per cluster, and water should be poured well to settle the roots while transplanting.
5. Field management
After the seedlings are transplanted and before they survive, water to settle the roots every morning and evening, and pay attention to checking the seedlings and filling in gaps to ensure a full stand. After transplanting and survival, apply manure water frequently and keep the soil moist. Before the rows close, carry out shallow intertillage 2-3 times. In hot and dry seasons, cover with a shade net on a greenhouse or small arch shed during the early growth stage, or build a frame and cover it with straw mats for shade. In particularly dry conditions, you can lead water into furrows for irrigation in the morning and evening when the water temperature is lower. Never let water rise above the bed surface; after the bed is moistened, drain the water quickly to maintain normal growth of celery.
6. Pest and disease control
The main diseases of celery are late blight and leaf spot, which can be controlled with zineb, carbendazim or chlorothalonil, etc. The main insect pest is aphids, which can be controlled with deltamethrin or dimethoate.