Lettuce (celtuce) planting time and methods: do these things well for a high yield

Celtuce is a common vegetable; its stems and leaves contain lactucin and it has high nutritional value. It has strong adaptability and can be cultivated in spring and autumn or overwintered, mainly in spring, with harvest in summer. So, what are the planting time and methods for celtuce? Do these things well for a high yield!

I. Planting time

Spring celtuce: raise seedlings in a greenhouse from December to March, or raise seedlings in the open field from mid-February to late March;

Summer celtuce: open-field cultivation in April to mid-May; from late May to July, use shade netting coverage, with direct sowing or high-density planting;

Autumn celtuce: from July to September, sow under shade netting coverage, raise seedlings and transplant;

Overwintering celtuce: raise seedlings in the open field from October to November.

II. Planting methods

1. Variety selection

For overwintering celtuce and spring celtuce, choose varieties that are cold-tolerant, highly adaptable and slow to bolt, such as Naihan Baiyejian, Naihan Erbaipi, and Kumaicai. For summer and autumn celtuce, choose heat-tolerant early-maturing varieties, such as Naihe Baiyejian, Kumaicai, Naihe Dadahuaye, Te Naihe Erbaipi, and oilseed lettuce (yóumàicài).

2. Soil preparation

Choose a plot with high, dry terrain and good drainage as the seedbed. 5-7 days before sowing, apply 4000-5000 kg of decomposed organic fertilizer or 500 kg of compound fertilizer per mu as base fertilizer. Apply before land preparation, then plow deep, level and refine the soil, and cover with plastic film while waiting to sow.

3. Raising seedlings

For sowing from May to September, because of the hot high temperatures, the seeds germinate with difficulty, so low-temperature pregermination is needed before sowing. Soak the seeds in cool water for 6-7 hours, then wrap them in a damp cloth and keep them at 20-25°C to pregerminate until 80% of the seeds have sprouted (white tips showing), then sow.

4. Sowing

Sow wet seeds and cover with film, then remove it after the seedlings emerge. After sowing, water and cover with a layer of decomposed pig manure slurry at 30-40% concentration and cover with a thin layer of rice straw, or cover with black shade netting; sow pregerminated seeds or wet seeds. Before emergence, cover the seedbed soil with a double layer of floating cover; after emergence, cover with silver-gray shade netting. Water with liquid fertilizer in the morning and evening, keep the seedbed soil moist, and weed and thin the seedlings in time.

5. Field planting

When field planting, choose loam soil with good drainage conditions and apply 4000-5000 kg of decomposed organic fertilizer per mu. Plow deep and level, and make raised beds 1.20-1.50 m wide. Before lifting the seedlings, water the seedbed first. When the seedlings are 25-30 days old and have 5-6 leaves, transplant them at a spacing of 20 cm × 27 cm, with the depth set so the base of the first leaf stalk is buried, and water to settle the roots after planting.

6. Field management

Water promptly after transplanting. After the transplants have survived, apply ammonium bicarbonate diluted in water at 8-10 kg per mu plus 10 kg of calcium superphosphate. After that, control water and fertilizer, strengthen cultivating, and from the rosette stage until the leaves close over the rows, water and topdress with 10-15 kg of urea and 5 kg of potassium sulfate per mu; afterward, water when the soil is dry and withhold when wet. When the stem begins to thicken, apply the third topdressing, with 50 kg of NPK compound fertilizer, 10 kg of potassium sulfate and 15 kg of urea applied in holes per mu.

7. Harvesting

Before the stem has fully thickened, tender plants can be harvested at any time for market. The harvest period of celtuce is also the period when bolting is fastest. If not harvested in time, the plant will bolt and the quality will become tough, or even hollow, greatly affecting the yield and quality of the celtuce; therefore celtuce must be harvested in time. When the top of the main stem of the celtuce is level with the tip of the highest leaf, that is the proper harvest time. Do not use pesticides for 10 days before harvest.