Cultivation of Special-Purpose Single-Clove Garlic and the Causes of Garlic Abnormalities
Single-clove garlic, I believe everyone has seen it; it is a fairly common type of garlic with special uses. So-called single-clove garlic means the bulb does not divide into cloves, having only one round ball-shaped clove. This single-clove garlic, because the plant lacks nutrients, develops poorly, and cannot produce a multi-cloved garlic bulb, has a rather unique pungent taste and certain medicinal value, with anti-cancer and sterilizing effects higher than ordinary multi-cloved garlic. Let's take a closer look below: How is single-clove garlic grown?Why does garlic develop this abnormal condition?
Although single-clove garlic has its special medicinal value, compared with multi-cloved garlic it is smaller in size, which seriously affects garlic yield, and the economic benefits of growing garlic are greatly reduced. Therefore, during garlic cultivation, people try their best to take measures to prevent single-clove garlic from occurring.
Like single-clove garlic, conditions that affect the economic benefits of garlic also include multi-cloved garlic and scattered-clove garlic. Besides affecting yield, these three conditions also affect garlic quality. So-called multi-cloved garlic refers to when the lateral buds of the bulb form cloves and then sprout again to form a secondary level of cloves. These secondary cloves are very small and at the same time divide the entire bulb into several garlic heads. Although the number of cloves and garlic scapes is much greater than normal, they are all very small, so their commercial value is low. Scattered-clove garlic, on the other hand, refers to when the cloves formed by the bulb sprout again before harvest to form new leaves, causing the entire bulb to grow many fine leaves and preventing the cloves from becoming plump.
Garlic is planted the same way, so why does garlic develop these abnormal conditions?
Causes of single-clove garlic: First, it is produced from secondary bulbs. Because secondary bulbs are small, they easily form single-clove garlic. Second, when planting garlic, cloves that are too small are used, so that at the beginning of bulb formation the amount of growth is small. Third, during the seedling growth process, lack of fertilizer or water, or damage from pests and diseases, causes the amount of growth at the beginning of bulb formation to be small.
Causes of multi-cloved garlic: This condition is relatively rare and is mainly caused by improper sowing. If garlic is artificially treated at low temperature before sowing in autumn and then sown, after overwintering, multi-cloved garlic will appear at harvest.
Causes of scattered-clove garlic: First, sowing too early in autumn, or excessive fertilizer and water in early spring during bulb formation. Second, harvesting too late, causing the stem disc of the bulb to rot in the soil before harvest, which leads the cloves to separate from one another and become scattered-clove garlic.
Methods to prevent these conditions: First, select larger cloves for seed retention. Second, sow at the appropriate time in autumn to prevent sowing too early. Third, during the garlic leaf growth process, strengthen fertilizer and water management so that the plant is larger when the bulb begins to form; after the bulb begins to swell, control the amount of fertilizer and water to avoid the young buds of the formed cloves turning green and growing leaves again. Fourth, harvest at the appropriate time to avoid harvesting too late. Fifth, strengthen management during storage to prevent clove scattering.
As for seed selection, how do you choose good seed? Mainly, before garlic is harvested, select some plants that mature early, grow well, and have high yield; after harvest, carry out single-bulb seed selection and eliminate those cloves with poor quality that are too weak and small. Try as much as possible to use cloves that are free from pest and disease damage, free from mechanical or human injury, thick-fleshed, and round and regular.
As for sowing, reasonable close planting should be carried out, with small shallow furrows opened for planting. First open a shallow furrow from one end of the plot, arrange the garlic cloves in sequence along one side of the furrow, and after arranging all the seed, apply base fertilizer in the furrow, then open a second furrow according to the row spacing, and use the soil from opening the second furrow to cover the first furrow, and continue in this way. However, different garlic types have different requirements, and how dense is reasonable must be determined according to factors such as the garlic variety's characteristics, soil fertility, fertilization level, and cultivation purpose.
I. Causes of single-clove garlic formation
1. Improper selection of seed garlic. When planting garlic, one should first select a garlic variety suitable for planting in the local area. Seed garlic should have large heads and plump cloves, with each clove clearly separate, with 4 to 8 cloves making up one garlic head. If seed garlic with small heads and thin cloves is selected, after sowing the seedlings grow weakly and have poor nutrient-absorbing ability, seriously affecting separation of the bulb disc and easily forming single-clove garlic. According to a 1999 survey, the single-clove rate of spring-sown small-clove seed garlic was 50% to 60%, while the single-clove rate of large-clove seed garlic was only 5% to 8%.
2. Poor soil. In poor soil or land where garlic has been continuously cropped, affected by soil quality and insufficient fertilizer, the seedlings are weak and the bulb disc develops poorly and cannot divide into cloves, forming single-clove garlic. According to surveys, for spring garlic with 1000 kg of chicken manure applied as base fertilizer per 667 sq m and 10 kg of urea applied after green-up and bolting, the single-clove rate was only 5% to 10%; without fertilizer, the single-clove rate reached 50% to 60%.
3. Improper sowing time. Garlic cloves are formed by the development of lateral buds in the leaf axils on the bulb disc, and are also affected by temperature, light, and nutrients in many ways. Therefore, sowing too early or too late will affect garlic growth and development. For example, spring planting is best done before the end of the 'nine' cold periods; if too late, the single-clove garlic rate will be high. Practice shows that spring garlic planted 5 to 7 days before the Spring Equinox had a single-clove rate of 10% to 15%, while planting 5 to 7 days after the Spring Equinox had a single-clove rate of 20% to 30%.
4. Excessive density. Farmers always want to plant garlic densely to save a bit of land, or think that increasing density can increase yield, but high density destroys the area that individual plants should occupy, causing garlic plants per unit area to compete for nutrients, resulting in insufficient fertilizer and space limitation, and forming single-clove garlic. Planting 35,000 to 40,000 plants per 667 sq m gave a single-clove rate of 30% to 40%, while planting 25,000 to 30,000 plants gave a single-clove rate of only 8% to 10%.
5. Poor management. Garlic has strong adaptability, but during growth it is very sensitive to environmental conditions, nutrients, and moisture. During management, poor individual growth is often caused by fertilizer and water, pests and diseases, and weeds, resulting in the bulb disc not easily differentiating buds or the individual being unable to form single-clove garlic through swelling.
II. Prevention and control of single-clove garlic
1. Choose high-quality garlic as seed. As the farming proverb says, “Good seed gives good seedlings, good seedlings give high yield.” Therefore, when planting garlic, the production purpose should first be determined. If the main purpose of planting is to produce garlic heads, then white-skinned garlic with large heads, obvious clove separation, and plump cloves should be selected as seed. If the purpose is to produce garlic scapes, then purple-skinned garlic with good heads and plump cloves should be selected as seed. Therefore, seed garlic must not be used indiscriminately.
2. Build soil fertility. For planting garlic, continuous cropping land should not be chosen. Garlic land needs deep ploughing and loosening of the soil, and increased application of organic fertilizer and phosphorus and potassium fertilizer. Per 667 sq m, 1500 to 2000 kg of farmyard manure should be applied as base fertilizer, plus 30 to 50 kg of phosphorus fertilizer and 15 to 20 kg of potassium fertilizer.
3. Strict sowing time. The suitable temperature for garlic bulb swelling is 20 to 25°C; above 26°C garlic enters dormancy, and when the sunshine duration is less than 13 h, although new leaves can continue to differentiate, lateral buds on the bulb disc cannot form. Therefore, when planting garlic, the sowing time must be strictly followed according to place and variety. In production, farmers often say: “Not at home at Mid-Autumn, not in the field at Dragon Boat,” and for spring garlic planting, “Spring garlic should not come out of the nine; if it comes out of the nine, it grows single-clove.” This clearly points out that autumn-sown garlic should be sown from the Autumn Equinox to Cold Dew, and spring-sown garlic should be sown when the soil begins to thaw at a depth of 5 cm, before the end of the 'nine,' that is, roughly before mid-March.
4. Reasonable close planting. Reasonable close planting is beneficial to the overall and individual growth of garlic. Generally, white-skinned garlic is arranged with row spacing and plant spacing of 16 cm × 10 cm, and the total yield is more than 25% higher than the control, with large heads and plump cloves. Red-skinned garlic is arranged with row spacing and plant spacing of 10 cm × 8 cm.
5. Strengthen management. The entire garlic growth cycle is divided into the germination stage, seedling stage, bulb bud differentiation stage, bulb bud swelling stage, and dormancy stage. Each growth stage should be grasped closely, but the bulb bud swelling stage is the focus of management. Fertilizer and water supply need to be strengthened: apply 10 to 15 kg of urea per 667 sq m as topdressing, water once every 3 to 5 days, and keep the soil surface from drying out. During this period, 600 times diluted monopotassium phosphate can also be sprayed on the leaves to supplement phosphorus and potassium fertilizer. Autumn-sown garlic also needs good management after autumn begins: cover with firewood, grass, and other materials before winter, uncover the covering promptly when spring warms, and water well at green-up. Entering mid-March, cultivation should be strengthened to help preserve soil moisture and raise soil temperature, and at the same time spray 1000 times diluted dimethoate to control root maggots.