Key Points for Garlic Sowing and Management

I. Autumn sowing should be carried out at the appropriate time.

Garlic should be sown at the right time. In most regions, autumn sowing takes place around the end of White Dew and the beginning of the Autumn Equinox—late September to early October—when temperatures are about 17°C. The optimal seedling age for overwintering is the 4–6 leaf stage; such seedlings can tolerate temperatures as low as −10°C. From sowing to the 4–6 leaf stage, it typically takes 40–45 days, after which growth ceases when the daily average temperature drops below 7°C. Therefore, sowing too early increases the risk of frost damage, while sowing too late exposes the crop to high temperatures later in the season, shortening the growing period, reducing yield, and compromising quality. Before planting, garlic cloves should be sun‑dried for 1–2 days.

II. Methods for Sowing Garlic

Optimal planting depth: For garlic, the recommended planting depth is typically 3 to 4 centimeters.

There are two sowing methods: (1) Planting by insertion: Insert the bulbils into the soil, cover them with soil after planting, and press down firmly. (2) Sowing in furrows: Use a hoe to make a shallow trench, then place the bulbils at spaced intervals within the trench. After sowing, cover with about 2 cm of soil, gently firm the surface with your foot, and water thoroughly.

To prevent drought, mulch the soil with two layers of straw or other moisture-retaining materials. Planting depth should also be adequate; planting too shallow can cause seedlings to “skip” their cotyledons, leading to insufficient water at the root zone during the seedling stage, poor root development, and increased susceptibility to frost damage and death over winter.

III. During sowing, appropriate planting density is required.

Appropriate planting density should be determined according to the characteristics of each variety, ensuring a sufficient number of plants per mu.

Early-maturing varieties typically have shorter plants, fewer leaves, and a shorter growing period; therefore, they require higher planting densities. It is advisable to plant approximately 50,000 plants per mu, with row spacing of 14–17 cm and plant spacing of 7–8 cm, using 150–200 kg of seed per mu.

Mid-to-late maturing varieties: With a longer growing period, these cultivars develop tall plants and produce more leaves; therefore, planting density should be slightly lower to ensure an optimal stand structure and maximize light utilization. A recommended planting density is approximately 40,000 plants per mu, with row spacing of 16–18 cm and plant spacing of about 10 cm, using roughly 150 kg of seed per mu.

IV. Mulching with Plastic Film

The use of plastic mulch in garlic cultivation significantly boosts yields. Data indicate that plastic mulching can increase the yield of garlic scapes by approximately 50% and the yield of garlic bulbs by about 40%.

After planting the garlic, begin by watering. About three days later, cover the garlic bed with plastic mulch, ensuring it is tightly sealed and firmly pressed down. Make sure the film lies snugly against the soil, with no gaps or wrinkles; if any holes appear, promptly seal them with soil to provide insulation for the garlic bed.

Note: Be sure to apply a herbicide before mulching. After sowing garlic and prior to mulching, you can spray herbicides such as chlorotoluron, isoproturon, oxadiazon, acetochlor, diquat, and pendimethalin.

V. Water Management After Sowing

For mulched garlic cultivation, irrigation is generally light and frequent. The first watering is applied immediately after sowing; the second is given as emergence nears; one watering is provided during the seedling stage; another before winter dormancy; a further watering during the green-up period; and one more during the scape‑differentiation phase. From 3 to 4 waterings are applied just before scape elongation, after which watering is stopped 5 to 7 days prior to harvest to facilitate scape extraction. Following scape harvesting, 3 to 4 additional waterings are administered. Mulched garlic bolts 5 to 7 days earlier than open‑field garlic.

6. Add a touch of garlic as desired.

Once the garlic has sprouted, use a rake or another tool to help the shoots break through the plastic mulch. For any that fail to emerge, gently hook them out with a small implement.

VII. Pay Attention to Stocking Fry

When garlic sprouts first emerge from the soil, promptly puncture the plastic mulch to allow the seedlings to break through. Typically, do this in the early morning or late evening—when temperatures are lower and the mulch is less elastic—by gently tapping the film with a new broom or lightly raking it with a bamboo rake.

VIII. Pay attention to the prevention and control of diseases and pests.

Attention should be paid to the damage caused by garlic maggots after sowing. The larvae feed on the seed coat and cotyledons, leading to malformation and rotting of the seedling bud and preventing emergence.

Preventive measures: Before sowing, treat the soil with a 1% formulation of avermectin granules or chlorpyrifos granules, then proceed with planting. Alternatively, during sowing, use a 60% imidacloprid suspension seed‑treatment agent to coat the seeds, which can help prevent infestation.

After sowing, if maggot damage occurs in garlic fields, apply a 2.5% cypermethrin or lambda‑cyhalothrin solution diluted 600–800 times, or a 22% chlorpyrifos–imidacloprid solution diluted 1,000 times, by drenching the roots; drenching before rain yields better results.