What are the common seed pre-sprouting methods for vegetables such as chili peppers and cilantro, and for cucurbits such as watermelon and pumpkin?

Usually the seeds need to be disinfected, soaked, and then pre-sprouted. After this treatment, the germination rate of the seeds will be greatly improved. Soaking and pre-sprouting help the seeds of leafy and cucurbit vegetables sprout quickly and uniformly, improve the utilization rate of the seedbed, and prevent seed rot caused by low temperatures in early spring, so what are the common seed pre-sprouting methods for vegetables and cucurbits?

Common vegetable seed pre-sprouting methods

1. Celery

Soak the seeds in clean water for 12-24 hours, then rinse with clean water and rub with your hands. After rubbing open the seed coat, spread the seeds out to dry. When the seeds are slightly dry, wrap them in a damp cloth and place them in a cool, shaded spot at about 20°C to pre-sprout; after 3-4 days they can be sown.

2. Celeriac

Soak the seeds in 48°C warm water for 30 minutes, then wrap them in damp gauze and place them at 15-20°C to pre-sprout, rinsing them frequently; after 7-12 days, when the seeds germinate, they can be sown.

3. Malabar spinach (ceylon spinach, tofu vegetable)

Soak the seeds in 25°C-30°C warm water for 1-2 days, and pre-sprout them at about 30°C; after about 7 days the seedlings emerge and they can be sown.

4. Spinach

Soak the seeds in clean water for 12-24 hours, stirring thoroughly in the water, and pre-sprout them at 10°C-15°C; after 3-4 days, when most of the seeds show white, they can be sown.

5. Lettuce

After washing the seeds, soak them for 5-10 hours, take them out and place them at a low temperature of 5°C for one day and one night, then spread them on a damp towel (gauze), cover with another layer of gauze to keep them moist, and pre-sprout them indoors in the light; sow after 1-2 days, keep the soil moist after sowing, and it is best for the seedlings to emerge without being covered with soil.

6. Cilantro (coriander)

Before sowing, first rub the seed fruits open, soak them in clean water for 12-24 hours, and place them in an environment of 20°C-32°C to pre-sprout; once most of the seeds have germinated they can be sown.

7. Water spinach

Soak the seeds in 50°C-55°C warm water, stirring constantly until the water temperature reaches 30°C, then keep soaking at a constant temperature for 5-10 hours; afterward take them out and wrap them in a damp cloth, and pre-sprout them at 20°C-25°C. Sow once most of the seeds have sprouted, and cover after sowing to keep them warm.

8. Carrot

Choose high-quality new seeds, rub off the prickles, and create good germination conditions. They can be sown after germination.

9. Garden pea

Choose high-quality new seeds, soak them in 25°C-30°C warm water for 1-2 days, and place them at 20°C-30°C to pre-sprout; once most of the seeds have germinated they can be sown.

10. Lettuce

After washing the seeds, soak them for 5-10 hours, take them out and place them at a low temperature of 5°C for one day and one night, then spread them on a damp towel, cover with another layer of gauze to keep them moist, and pre-sprout them indoors in the light; sow after 1-2 days, keep the soil moist after sowing, and it is best for the seedlings to emerge without being covered with soil.

11. Chili peppers, tomatoes:

1. Chemical soaking: soak in 10% trisodium phosphate solution for 20 minutes or 0.2% potassium permanganate solution for 20—30 minutes, which can inactivate viruses carried by the seeds.

2. Soaking: generally soak the seeds in 50—55°C warm water; when the seeds are placed in the warm water, stir constantly, and stop stirring when the water temperature drops to 30°C, then soak for 3—4 hours, but be careful to prevent the water temperature from being too high and scalding the seeds to death, or the soaking time from being too long and suffocating the seeds to death. After soaking, let the seeds cool for a while, then wrap them in gauze and place them in a 25—30°C constant-temperature chamber. If there is no oxygen supply, the seeds cannot germinate; under severely oxygen-deficient conditions, harmful substances such as ethanol are produced and accumulate, causing embryo poisoning and seed rot.

The soaking time is related to how old the seeds are and the water temperature; for new seeds and when the water temperature is higher, the soaking time can be shorter. During pre-sprouting, turn the seeds frequently and rinse them with warm water so that the seeds are evenly warmed and keep breathing. Where conditions permit, pre-sprout in a constant-temperature chamber; if there is no constant-temperature chamber, it can be done on the flue of a heated greenhouse, beside a stove, or on a radiator, but the seeds must not come into direct contact with the heat source, to avoid steaming the sprouts. The wrapped seeds can be placed in a clay pot with sorghum stalks, rice husks, sawdust, or similar regulating materials at the bottom to pre-sprout. The pre-sprouting time must not be too long, to avoid the sprouts growing too long; overly long sprouts are easily broken when sowing. If sowing must be delayed for special reasons such as weather, the pre-sprouting temperature can be lowered to 5~10°C to delay germination.

12. Brassicaceae: Chinese cabbage, radish, cabbage, cauliflower, rapeseed, mustard, potherb mustard, etc.

The germination temperature of these vegetable seeds is 15-30°C, a wide suitable temperature range. Because the seed coat is thin, there is no need to soak the seeds; sow them directly in a small petri dish, using the paper germination method, and the seeds do not need to be rinsed during germination.

13. Liliaceae: scallion, onion, Chinese chives, fennel, seaweed, etc.

These seeds have lower temperature requirements; they can germinate well only at a constant temperature of 15°C or 20°C. If the temperature is too high the seeds do not germinate, and if the temperature is too low the seeds' physiological processes continue, which is unfavorable for germination. Except for celery seeds, which are not soaked, the other seeds are best soaked in warm water for 5-7 hours, using small or medium petri dishes; most seeds use paper as the germination bed, while coriander seeds are best germinated in soil, spraying a small amount of water during germination. The germination period is 6-14 days, and coriander takes longer, requiring 7-21 days.

Seed pre-sprouting methods for various cucurbits

1. Cucumber

Disinfect the seeds before sowing by soaking them in 50°C constant-temperature water for 15 minutes, stirring constantly, then add cold water to bring it to room temperature and soak for another 2-5 hours. Take them out, drain them, and place them at 25-28°C to pre-sprout; after 1.5-2 days, when the radicle first shows, they can be sown.

2. Watermelon

Sun the seeds for 1-2 days before sowing, soak them in 55°C hot water for 10-15 minutes, stirring constantly, then soak them in cold water for 4-6 hours, and then place them at 20-30°C to pre-sprout, rinsing the seeds with warm water once every day at noon. They can be sown after 4-5 days when they show white.

3. Winter melon

Before sowing, place the seeds in 50-60°C hot water, stirring constantly so the seeds are heated evenly; after 13-15 minutes, when the water temperature drops to 30°C, stop stirring, rub and wash the seeds with your hands, and remove the shriveled seeds.

Remove the mucus, change to clean water and soak for 12-14 hours. Once the seeds have absorbed enough water, take them out, wrap them in a thick cloth, and place them in a germination chamber or another warm place (temperature 30°C) to pre-sprout.

Turn the pre-sprouting seeds once a day so that the temperature inside and outside the seed pile is consistent. When turning the seeds, check the moisture status; if the seeds are found to be too dry, spray water in time. They will sprout in 3-4 days.

4. Pumpkin

Sun the seeds for 1-2 days before sowing, soak them in 50-60°C hot water for 5-10 minutes, stirring constantly; when the water temperature drops to 25-30°C, soak for another 6 hours, take them out and drain them, and pre-sprout them at 20-30°C, taking care to maintain good ventilation. They will germinate in 2-3 days.

5. Bitter melon

Bitter melon has a hard seed coat. Before sowing, rub off the waxy layer of the seed coat with wet sand (do not rub through the seed shell), place the seeds in 50-60°C hot water and soak for 10 minutes, stirring constantly; after it cools, continue soaking for 1-2 days so they absorb water and swell. After soaking, place them at 30-33°C to pre-sprout.

6. Melon

Sun the seeds for 2-3 days before sowing, place the seeds in 50°C warm water and soak for 10 minutes, stirring constantly; let them cool naturally with the water temperature, soak for 1 hour, then disinfect the seeds with a 1000-fold carbendazim solution for 10-20 minutes. After rinsing clean, wrap them in gauze and pre-sprout them at 28-30°C; they can be sown once the seeds show white.