Pre-sowing preparation of vegetable seeds for greenhouses

Seed sorting and disinfection before sowing

High-quality pre-sowing preparation allows for the selection of the most viable seed and reduces the risk of disease development in the greenhouse. The work begins with calibration, which helps to remove small and damaged specimens. Among all methods for small batches of seed, dry sorting by appearance or using physical devices is best suited.

1. Sieve cabbage seed through a screen with a mesh diameter of 1.25–1.3 mm to separate the high-quality fraction.
2. For other vegetable crops, spread the seed in a thin layer on a flat surface.
3. Rub an ebonite or plastic handle with a woolen cloth and pass it over the seed at a height of 1–2 cm.
4. Repeat the operation twice. The plastic will act like a magnet: first, the small and empty seed will be attracted, and then the large ones.

The next mandatory stage is disinfection, as most vegetable crop diseases are transmitted through seed material. The disinfection method is selected individually for each crop, strictly observing the temperature regime and exposure time.

• Sieve mesh diameter for cabbage — 1.25–1.3 mm
• Heating temperature for cabbage seed — 50 °C
• Thermal treatment time for seed — 20 min
• Cooling time for seed in water — 3 min

Germination stimulation and soaking

To increase germination, accelerate growth, and improve resistance to adverse conditions, seed is treated with solutions of mineral fertilizers and biostimulants. Soaking initiates growth processes even before sowing into the soil. For these purposes, both ready-made chemical preparations and time-tested organic compounds are used.

To increase plant productivity, the practice of soaking seed for 12–16 hours at a temperature of 20 °C in a solution of macro- and micronutrients is used.

For complex growth stimulation, increasing immunity to diseases, and reducing nitrate concentration, it is effective to soak seed followed by foliar top dressing with a special multi-component solution.

Seed treatment with purchased micronutrients or pure sodium humate is permitted. Sodium humate is prepared a day before use: it is poured over with warm water and stirred periodically. When treating large batches of seed, a concentrated stock solution is made first.

In vegetable production, alternative and traditional methods of soaking seed before sowing are also used:

• Wood ash infusion: 20 g of ash is infused in 1 l of water, stirred, and the seed is kept in it for 12–16 hours.
• Organic solutions: livestock animal urine in a concentration of 20–25% or an aqueous solution of cow manure (1 part to 7–10 parts water) with mandatory subsequent rinsing with water and drying.
• Natural stimulants: meltwater or aloe juice diluted with water in a ratio of 1:2 or 1:4. Aloe leaves are pre-kept in the refrigerator to activate protective properties.
• Biostimulants: preparations such as Ivin, Immunocytophyte, and also Gumisol based on bio-humus.

Experiments also evaluated the influence of prayer on the sowing qualities of seed. According to the results of practical trials, prayer for assistance in growing a harvest had a stronger influence on the speed of seedling emergence and overall germination than biological stimulants, including aloe juice and wood ash with honey. The effectiveness of this method is attributed to the person's faith and lifestyle.

Seed soaking, bubbling, and hardening technologies

Pre-sowing preparation accelerates emergence and improves its uniformity. When evaluating the effectiveness of growth stimulants, use seeds soaked in clean water as a control, not dry ones. Water itself triggers germination processes, while physiologically active substances increase germination by a maximum of 10% compared to conventional soaking in clean water.

Follow the procedure when soaking: keep slow-germinating seeds in water for 1–2 days, and fast-germinating ones for 8 to 12 hours. The water must be changed 2–3 times to wash out germination inhibitors. Seeds are germinated between layers of moist fabric; the thickness of the seed layer should not exceed 1 cm to ensure aeration. To increase germination energy and for partial disinfection, bubbling is used — keeping the seeds for 12–24 hours in oxygen-saturated water (in home gardening conditions, an aquarium compressor can be used).

• Germination increase from stimulants — up to 10 %
• Seed layer thickness during aeration — up to 1 cm
• Seed bubbling time — 12–24 hours
• Hardening temperature for tomatoes — from 0 to -3 °C
• Harvest yield increase for cucurbits from heating — 20–30 %

Hardening increases the resistance of plants to low temperatures, but it is a delicate procedure that, if performed incorrectly, reduces germination. For early planting of tomatoes, seeds are hardened after 5% of them have sprouted. The seeds are placed for 3 days in a snow pile or on ice at a temperature from 0 to -3 °C.

Pelleting of seeds (incorporating nutrients, growth substances, and fungicides into the coating) is advisable only when using precision seeders. For manual sowing, it is not recommended to use pelleted seeds, as it may delay emergence.

Specifics of preparing seeds of cucurbits and small-seeded crops

Seeds of cucurbits (cucumber, watermelon, melon, pumpkin) require mandatory heating, especially if annual seed material is used. Two- and three-year-old seeds of these crops are physiologically more productive and ensure higher yield. Heating allows for a yield increase of 20–30 %. In a thermostat, seeds are heated for 3 hours: first at a temperature of 25–20 °C, then it is raised to 50–60 °C. Alternatively, 1.5–2 months before sowing, you can hang bags with cucurbit seeds in a room near radiators.

To protect cucumbers, zucchini, summer squash, and pumpkins from downy mildew, which is transmitted by seeds, the seed material is polished by a dry method after heating:

1. Place the heated seeds in a tightly sealed metal container.
2. Add a few pinches of starch to the container.
3. Shake and rotate the container vigorously for several hours (friction will remove the pathogen-infected film).
4. Pour out the seeds and separate them from the starch before further processing.

After polishing, cucurbit seeds are disinfected in a potassium permanganate solution, treated with physiologically active substances, and germinated. Preparation schemes for other vegetable crops are shown in the table.