Technologies for growing high-quality vegetable seedlings in hotbeds

Quality transplants are the basis for high vegetable yields in open soil and provide an opportunity to obtain produce at an earlier date. The transplant method also shortens the growing season for certain biennial crops. For example, bulb onion with this approach produces a full-grown bulb in the very first year instead of two years with standard sowing of seed.

• Tomato yield in open soil — 56 t/ha
• Maximum cabbage yield in experiments — 1367 centners/ha
• Cucumber yield — 28.5 t/ha
• Hotbed requirement for double picking of tomatoes — 40 frames instead of 120

Double picking of tomatoes and transplant hardening

Applying the double picking method allows for a significant reduction in the area required for transplants in hotbeds during the initial stages. In practical trials, tomato seed were sown on April 6 in warm hotbeds. Two weeks later, seedlings were pricked out into semi-warm hotbeds with a growing space of 6x6 cm. On May 15, a second picking was carried out into open soil on warmed ridges, increasing the growing space for each plant to 10x10 cm.

Ridges for the second picking were lined with manure and boards, and covered with mats at night. This approach allowed for the cultivation of healthy, hardened transplants with a well-developed root system and occupied only 40 hotbed frames instead of the usual 120 with standard cultivation. The method significantly saves useful space in greenhouse management at the beginning of the season.

When growing cabbage, transplant hardening and transplanting them with a soil ball without damaging the roots also play a decisive role. The late-maturing cultivar "Slavyanka" was sown in hotbeds on April 2, maintaining the temperature at 10–12 °C. For hardening, the frames were regularly ventilated and completely removed on warm days. Ten days before planting, the hotbeds were left open at night, protecting them only when there was a risk of frost.

Technology for growing cabbage in hotbeds

The choice of hotbed type and cabbage sowing dates depends on the earliness of the cultivar. Timely sowing and adherence to temperature regimes prevent plants from becoming leggy and ensure a high yield of viable seedlings.

Care for cabbage seedlings after emergence is structured in a strict sequence:

1. Start ventilating the hotbeds at the first signs of emergence (4–5 days after sowing) by slightly opening the frames.
2. Maintain a temperature of 5–7 °C for the next 2–3 days.
3. Monitor the temperature during further growth, preventing it from rising above 15 °C.
4. Perform picking at the first true leaf stage into empty hotbeds using a dibber or finger with a growing space of 6x6 or 6x5 cm (400–500 plants per frame).

Over the entire period of transplant cultivation, 2 to 3 liquid fertilizer applications are performed. The first application is made 10–12 days after emergence using an organic solution. To prepare the concentrate, a container is filled 3/5 full with cow manure, liquid manure, or excrement, and the remaining 2/5 volume is topped up with water.

The second top dressing is carried out 15–20 days after the first, using the same organic solutions or a mixture of mineral fertilizers. For a mineral solution, take the following per one bucket of water (10–12 l):

• Nitrogenous fertilizer — 20 g;
• Superphosphate — 30 g;
• Potassium salt — 15 g.

If a full set of mineral fertilizers is unavailable, a solution can be prepared using only nitrogenous or potassium fertilizers in the same amounts. Watering with potassium has a beneficial effect on the frost resistance of transplants in open soil. A third top dressing with organic or mineral fertilizers is carried out 10–12 days after the second.

Transplants of cabbage are planted in open soil when they have formed 4—5 leaves (and cauliflower 3—4 leaves). 7—10 days before planting, while still in the hotbeds, the transplants are acclimated ("hardened") to the outside air. To do this, initially for 3—4 days, the frames are removed during the early morning and late evening hours on sunny days. During the day, from approximately 10 a.m. to 5 p.m., the frames are closed. On overcast days, the frames are left open all day. In the following 4—5 days, the frames are removed at night as well, and are closed at night only if frost is expected.

This is how transplants are gradually prepared for growth conditions in open soil.

Transplanting from hotbeds to open soil, just like pricking out, is still perceived by plants as stressful. The root system and leaves of the plants are partially damaged, and it takes some time for them to take root in a new location.

Pricking out, furthermore, requires additional labor costs, which is why this work is often delayed. This is why some state and collective farms are abandoning pricking out and growing transplants without applying it. In this case, a sparser sowing is performed—4—5 g of seed per frame with a yield of 400—500 seedlings. However, we believe that in the conditions of the Leningrad Region, one should not abandon pricking out. This is confirmed by the practice of achieving high yields by the Stakhanovite vegetable growers of our region and by the experiments of the Leningrad Fruit and Vegetable Institute.

One should try to transplant plants with a clod of soil around the roots, so that the roots will be less damaged.

Гы м К сч.- ы гт А < т

To completely avoid the stressful period in plant growth during transplanting, it is best to grow transplants in peat or peat-manure pots.

The advantage of growing in peat or peat-manure pots lies in the fact that during transplanting together С а Фа мора > } Вх ВЕНЫ у хе

Г fig. 8. General view of the pot-making machine. A — handle; B — stamp; C — bolt; D — bracket; E — stand; F — pedal. With the pot, the roots and leaves of the plant are not damaged, and the plant continues to develop normally.

The manufacturing technique for these pots is simple and accessible to every farm, and the material is available everywhere locally.

The pot-making machine can be made by yourself. It consists of a table with legs made of beams with a cross-section of 80x80 mm and a height of 745 mm. The tabletop is made with dimensions of 700x500 mm from planks 60 mm thick. A hexagonal hole with a diameter of 72 mm is made in the top; above which a block is attached with a hole slightly larger than the hole in the table. An iron pressing mold made of millimeter-thick iron is inserted into the hole of the table and the block.

From above, the mold is pressed by an iron sheet with the same hole. Above the sheet is a freely rotating iron lid with a handle on an axis. The axis is a bolt 10 mm in diameter and 130 mm long. A limiter is installed on the side of the handle to regulate the movement of the lid.

A lever (A) with a stamp (B) is hinged to the machine, which rotates freely on a bracket (D). The lever is made of strip iron 10 mm thick.

While filling the mold with peat, the lever is placed on the stand (E). At the bottom of the table, a piston with a pedal (F) is installed, which serves to eject the formed pot by pressing the pedal.

The molding of the pot proceeds in the following order: The mold is filled three-quarters full with peat and covered with the iron lid. By pressing the lever, the stamp is inserted into the hole of the lid, and the pot is molded. Then the lever is raised, the mold lid is opened, and by pressing the pedal, the finished pot is ejected.

On the described machine, it is possible to produce pots of only one size. But there are more complex machine designs on which pots of different diameters can be produced.

Pots are dried gradually in places shaded from the sun or in specially adapted rooms.

Another drying method is also recommended — freezing the pots. This method is simpler and more convenient. It is best to manufacture the pots in the winter. Drying them in rooms (on heating pipes in greenhouses, in houses, bathhouses, etc.) is difficult; meanwhile, the process of freezing them is very simple. The pots are taken out under a canopy, into a shed, or another cold room and kept there for several days. After freezing, they are stacked in crates, baskets, and stored in piles. Before the arrival of warm weather, so that the pots do not thaw, the piles are covered with peat, sawdust, mats, or other materials. 2—3 days before sowing (planting), the pots are placed in the soil of the hotbed or greenhouse. The formed mass in the soil warms up, thaws, and one can sow into it or transplant seedlings when pricking out.

Frozen pots also create better conditions for plant growth. When thawing, the peat mass becomes moist and soft, and plant roots easily penetrate it;

The preparation of the mixture for making pots Fig. 10. Rack for drying peat pots should be approached with special care,

The best material for making pot mass is lowland medium-decomposed sedge peat. You can add 10–20% sod soil or 10% sod soil and 10% cow manure to the peat,

One cubic meter of peat yields 1500–2000 pots,

Seedlings grown in hotbeds or greenhouses are pricked out into prepared pots. Before starting the pricking out, the pots are arranged in dense rows in the hotbeds.

Growing transplants in pots is a reliable method to obtain high-quality plants with a protected root system. The technology is especially recommended for tomatoes, cucumbers, zucchini, pumpkin, and early cabbage cultivars. Plants are transferred to their permanent location together with the container, which prevents root injury and eliminates growth retardation.

To properly set the pots in a hotbed, follow this sequence of work:

1. If the transplants are being grown in the first frame rotation, spread a layer of soil 5–6 cm thick over the manure.
2. Fill the pots with a nutrient mixture of sod and old hotbed soil.
3. Place the pots in the hotbed, fill the gaps between them with soil, and cover with a 1–2 cm layer of soil on top so that the containers are completely buried.
4. Make a hole in the center of each pot with a peg and prick out the seedlings there.
5. Firm the soil around the plant stems, water them, and shade the hotbed with mats.

• Thickness of the soil layer over manure — 5–6 cm
• Thickness of the covering layer over the pots — 1–2 cm
• Water consumption for irrigation — 1 bucket per frame
• Shading period with mats — 2–3 days

The required hotbed area is calculated based on the planned output of ready-to-plant transplants per unit of growing space.

Non-pricking method for growing mid-season cabbage cultivars

Mid-season cabbage cultivars, such as Valvatyevskaya and Slava, can be grown using a simplified scheme without pricking out. For this, nursery beds or warmed garden beds are used. Sowing is carried out in rows using a 4x4 cm spacing, with the rest of the care remaining standard. If the spring is warm, transplants of these cabbage cultivars can be grown directly in the field.