Cultivation technology for asparagus lettuce and radish in protected soil

Asparagus lettuce is grown using the transplant method, which allows for saving seed and obtaining high-quality produce. The sowing time in a greenhouse or hotbed is the second half of April. Until emergence, the temperature in hotbeds or greenhouses is maintained at 20—25 °С. On the fourth or fifth day after emergence, the temperature is reduced: in sunny weather during the day to 16-18 °С, in cloudy weather to 14-16 °С, and at night to 10-12 and 8-10 °С respectively.

Upon the formation of the first true leaf, thinning is carried out at a distance of 4—5 cm between plants, followed by irrigation. The yield of transplants from 1 m² is 400—600 units, which ensures planting on an area of 25-30 m². Transplants are planted in open soil in May at the age of 30-35 days in rows at a distance of 50 cm, with 30 cm between plants in a row.

For good establishment in open soil, transplants are watered daily; after establishment, the soil is loosened and watered with an application of mineral fertilizers.

In the conditions of the temperate zone, asparagus lettuce is harvested 110-120 days after sowing.

Radish is an annual plant belonging to the cabbage family. It is light-loving; if shaded, it forms small root crops. It is a long-day plant.

Radish seedlings withstand frosts down to -3 °С, and adult plants down to -5 °С. Optimal temperature for root crop growth is 18—20 °С. Overheating in film structures during radish cultivation leads to a decrease in root quality, flabbiness of the flesh, and the appearance of cavities.

The plant is demanding regarding soil fertility: in acidic soil, radish is heavily affected by clubroot. With a nitrogen deficiency, the root crop and leaves develop poorly, with the latter turning pinkish-crimson. Potassium deficiency delays the formation of the root crop.

In film greenhouses, radish is sown in early April, and in covers — in mid-April. Soil is prepared for the main crop. Sowing is carried out using a marker with a furrow spacing of 6x6 cm or by broadcasting. Seed application rate is 2—4 g per 1 m². Seeds are planted at a depth of 2—2.5 cm.

Until emergence, the temperature is maintained at 15-20 °С. Upon emergence, it is reduced to 8-10 °С to prevent the stretching of the hypocotyl. This temperature is maintained until the formation of the first true leaf, and then it is increased to 15-18 °С during the day and 8-12 °С at night.

Plants are watered regularly: moderately before the beginning of root crop formation, and abundantly during its growth period.

Top dressing is carried out at the beginning of root crop formation with a solution of 20 g of ammonium nitrate and 30 g of potassium chloride per 10 l of water.

Harvesting is carried out selectively over 7-10 days. Root crops are stored in a refrigerator in plastic bags for up to 30 days. Radish can be stored in boxes buried in the ground to a depth of 25-30 cm.

Onion is a cold-resistant plant. Its seedlings appear at a temperature of 1-2 °С, but seeds germinate faster at 18—20 °С. Onion seedlings withstand frosts down to -2 °С. When grown from seed, onions require loose, fertile soils and plenty of light. When forcing greens from bulb onions, it is undemanding regarding light and soil nutrients.

There are several ways to obtain onion greens. For earlier greens, bulbs are planted in the autumn, which eliminates the need for storing planting material over the winter. Bulbs are planted two weeks before steady cold weather (soil freezing) at a distance of 2-3 cm from each other. Planting rate is 3-6 kg per 1 m². Pre-winter planting of onions is performed on well-fertilized sandy or sandy-loam soils, in areas that are cleared of snow and meltwater early. Planted bulbs are covered with a layer of soil, peat, or humus, 5-7 cm thick. When covering plantings with strawy manure, plant losses increase, especially in winters without snow but with thaws.

In late March — early April, snow is cleared from the onion plantation and the soil covering is raked away. Film or portable greenhouses are installed on the site. During the forcing period, the plant is watered 1-2 times, and the cover is thoroughly ventilated. Onion greens are harvested 18—20 days after the installation of film covers.

Early spring planting of onions in greenhouses and hotbeds ensures the next harvest time for onion greens. Bulbs are planted 5-8 cm apart and watered after planting. After 2 weeks, top dressing is applied with a urea solution (20 g per 10 l of water), with an application rate of 5 l of solution per 1 m². Then, plants are watered abundantly to wash fertilizer off the leaves. Harvesting of greens is carried out 30 days after leaf regrowth.

When planting onion sets in late April under temporary plastic covers, you get green onions later. Planting of sets is done in loose, well-fertilized with humus plots cleared of weeds. 1.5—2 kg of onion sets are planted per 1 m². During the growing season, the plants are top dressed 1—2 times with a solution of 10 g of urea, 15 g of superphosphate, and 15 g of potassium chloride per 10 l of water.

The harvest of greens is collected in mid-June. During harvesting, plants are left every other row until the formation of bulbs. Plastic covers are removed at the end of May.

Green onions can also be obtained from transplants. To do this, onion seeds are sown in early March in 5x5 cm pots, 5-8 seeds in each. To accelerate emergence, seeds are soaked for 3 days, changing the water daily, or soaked for 8 hours in water at a temperature of 40 °C.

Before the emergence of onions, the temperature is maintained at 20—22 °C, after emergence — 15-16 °C during the day, and 8-10 °C at night. Transplants are planted out at the age of 60—70 days in the 2—4 true leaves phase.

When planting transplants, the distance between rows is 20-25 cm, and between groups of plants — 15—20 cm. Two weeks after planting, the plants are top dressed with a mullein solution (1:10). You can carry out top dressing with a urea solution (15 g per 10 l of water). Onions are watered regularly, the soil is loosened after watering, but shallowly, since the root system of the onion is located in the top layer of the soil. Plastic covers are installed immediately after planting onions in early May and removed when warm weather arrives so that the leaves do not turn yellow.

Green onions are harvested from mid-June. Onions grown from transplants, as a rule, do not produce flower stalks.

To extend the production of green onions, in May, onions are sown directly into the soil. Before sowing, 4-5 kg of humus, 20—30 g of superphosphate and ammonium nitrate, and 10-20 g of potassium salt are applied per 1 m². The sowing rate of seeds is 1.5-2 g per 1 m². The sowing scheme is 3—5 rows with a distance of 7-8 cm.

The sowings are mulched with peat or humus and a plastic tunnel cover is installed on the bed. When the weather warms up, the cover is removed.

The plastic film can be laid directly on the bed, covering its edges with soil. After emergence, the film is removed.

Green onions are obtained 60—70 days after mass emergence. During this time, maintenance work is carried out:

• Carrying out 3—4 irrigations.
• Application of a urea solution (20 g per 10 l of water) during one of the irrigations.

Green onions are obtained in early spring by planting in hotbeds and under plastic film. Bulb onions for forcing of leaves can also be planted before winter: bulbs are planted densely, using the bridge method, and covered with a 5-6 cm layer of peat.

One should not forget about other less common perennial onion cultivars, suitable for obtaining green leaves both in protected ground of greenhouses year-round and in open ground in early spring. They sometimes surpass common onion leaves in taste, aroma, storage quality, and other quality indicators. As a rule, the greens of perennial onion cultivars are richer in vitamins and other beneficial nutrients than those of common onions.

Chives are perennial plants distinguished by high frost resistance. They grow in the Far North and in Siberia, which is why they are also called Siberian onions. In early spring, the onion produces awl-shaped, hollow leaves. The leaves are very tender from spring, do not coarsen for a long time, and the taste is not particularly sharp, but rather bitter. The flower stalks of the onion hardly differ in taste from the leaves; they are just as tender and quite suitable for food. The bright green awl-shaped leaves grow in dense bunches, and the flowers are purple. Onions are used to border flower beds, paths, and tree trunks of fruit trees, where they act as an insecticide (repelling insects). The greens are distinguished by a high carotene content.

Chives have almost no dormancy period; under favorable conditions, they are capable of growing continuously.

Shallot is a vegetatively propagated form, once bred from common onions. The bulb of a shallot divides into several small bulbs attached to a common base and covered with a common skin (like garlic). The bulbs store well and, when planted in the ground, produce green leaves as early as the 15th—20th day. The leaves are flattened, with a waxy bloom, and have a very tender taste. Although the bulbs are small, they are delicious.

Leeks stand apart — both their taste is original and their aroma is more delicate. The essential oil does not irritate the respiratory organs and does not leave a heavy onion odor after eating, although it contains more essential oil than other types of onions. Both the green leaves and the tender, blanched thickening of the stem are used for food.

Welsh onion is a perennial plant. It accumulates nutrients in bulbs that overwinter in the soil. The plant has high winter hardiness. In early spring, after the snow melts, vitamin-rich green leaves emerge from the overwintering bulbs.

Welsh onion is demanding regarding soil: it must be loose and fertile. The plant can tolerate drought, but regular and timely irrigation significantly increases the yield of green leaves.

For the plant, choose plots that are free from snow early and protected from northern winds. The best predecessors are cabbage, tomatoes, and potatoes. When digging the plot, apply at least 10 kg of humus or manure, 20—30 g of ammonium nitrate, 30—40 g of superphosphate, and 15-20 g of potassium chloride per 1 m².

Seeds are sown in rows, with a distance of 20 cm between rows. The seed rows are covered with a 1—1.5 cm layer of humus.

With early spring sowing under plastic covers, Welsh onion is harvested along with the false bulb in August (growing season of 4.5—5 months). When sown in July, harvesting is performed in May-June of the following year. As a perennial crop, Welsh onion is sown in July; with this sowing date, the plants bolt less. If propagation is carried out vegetatively, the best planting time is August.

Cultivation of Welsh onion and broadleaf onion under plastic

• Welsh onion plantation usage period — 2–3 years
• Broadleaf onion application rate — 15 g/m²
• Frost resistance of tree onion — down to -40 °C
• Daytime forcing temperature — 20–25 °C
• Green forcing period in a greenhouse — 1 month

Care for Welsh onion plantings includes regular weeding and loosening of the soil. When establishing a perennial plantation, seedlings are thinned to a distance of 4–6 cm at the 3–4 leaf stage. During this same period, plants are given a top dressing: apply 10 g of superphosphate, 15 g of ammonium nitrate, and 8 g of potassium chloride per 1 m².

In spring, before the soil thaws, old leaves are raked off the beds and plastic covers are mounted. Under the plastic, Welsh onion is ready for cutting significantly earlier than in open soil. After cutting, the cover is moved to heat-loving crops, and the Welsh onion plantation is given a top dressing.

For top dressing, use a mullein solution or manure slurry (1:5) at a rate of 0.5 l per 1 m². Organic top dressing is alternated with mineral fertilizers: 60 g of ammonium nitrate, 40 g of superphosphate, and 30 g of potassium chloride per 10 l of water. This volume of solution is used for 2–3 m² of plantings. After application of fertilizer, plants must be irrigated with water.

Cutting of Welsh onion greens is carried out up to 5 times per season. The final harvest of the leaves should be done no later than August 1. The plot is used for green production for 2–3 years, after which the bulbs are completely dug up when the plantation is liquidated.

Broadleaf onion (Allium latifolium) is characterized by early regrowth of flat leaves 2–3 cm wide and up to 40 cm tall. The plant is winter-hardy, does not freeze out in northern regions, is resistant to disease, and has a pleasant mild-spicy taste. The flat, tender leaves of the broadleaf onion are rich in vitamins and iron salts, which makes it useful in the treatment of anemia. However, the flowering stalks of this onion are inedible.

Broadleaf onion is grown in one place for up to 7 years, propagated by seed or division of the clump. Young plants tolerate spring frosts down to -5...-6 °С well. Soil for the crop is prepared from autumn, applying 4 to 6 kg of humus and 30 g of superphosphate per 1 m². During spring digging, 20–25 g of ammonium nitrate, as well as 20 g each of superphosphate and potassium chloride per 1 m², are added.

Seeds are sown in spring or summer (no later than early August) with a distance of 20–25 cm between plants. The sowing rate of seeds is 15 g per 1 m². After emergence of seedlings, the onion is given a top dressing with a mullein solution (1:8), poultry manure (1:20), or nitroammophoska at a rate of 60–70 g per 1 m². Leaf harvesting is carried out periodically, by cutting the greens or removing several false bulbs from 3–4-year-old clumps. In dry weather, the plantation is irrigated, after which the soil is loosened and mineral fertilizers are applied.

Cultivation techniques for tree onion and greenhouse forcing

The leaves of the Egyptian onion are tubular, growing up to 50 cm in height and reaching a thickness of up to 2 cm. In spring, they grow back very quickly, especially when using film covers. The crop is extremely frost-resistant and withstands temperature drops down to -40 °С. Aerial bulbs (bulbils) retain germination capacity even after overwintering directly on the soil surface. This onion is grown in one location for 4–5 years.

Before planting the Egyptian onion, the soil must be well fertilized. Application rates of fertilizers per 1 m² are shown in the table:

The planting pattern and depth depend on the condition of the planting material and the timing of the work. Bulbs planted in late July or early August take root quickly and begin to produce greens in the same year. With autumn planting, bulbils only manage to take root, while those planted in spring will produce greens in the second half of the summer.

1. Select bulbs from the first and second tiers for planting.
2. Plant them immediately after root tubercles or small roots appear on the basal plate.
3. Place the bulbs according to a 20 (35) x 20 cm pattern, planting at a depth of 3–5 cm.

In spring, dead leaves are raked off the beds, 10 g each of ammonium nitrate, superphosphate, and ammonium chloride are applied, after which the soil is loosened. Film covers are installed over the beds and removed immediately after the greens are cut. Further care consists of regular soil loosening, weeding, and irrigation. By the 3rd or 4th year, the plantation becomes very dense, so the clumps are thinned out, leaving 1–2 basal bulbs.

Bulbs dug up during thinning or plantation removal are used for food or for forcing greens. In heated greenhouses, forcing is carried out in late autumn by planting basal and aerial bulbs into moist soil. For successful growth, the temperature is maintained at 20–25 °С during the day and 16–18 °С at night. Harvesting of marketable greens together with the bulbs is performed exactly one month after planting.