Key Technical Points for High-Yield Cultivation of Green Food Garlic

1 Site Conditions for Green Food Garlic

The green food garlic base should be far from cities, industrial and mining areas, and main traffic lines, and there should be no "three wastes" discharging enterprises in the base area and its surroundings. The farmland atmospheric environment should be good, and the irrigation water quality and soil environmental quality should both comply with the "Environmental Quality Standard for Green Food Production Areas." Soil suitable for garlic growth should have a deep plow layer and fertile texture, with organic matter content above 1.0%, and loam is best.

2 Planting of Green Food Garlic

2.1 Land Preparation

The plowing depth is generally about 20 cm. The soil should be finely cultivated, leveled, and compacted, with no obvious clods, achieving "level, loose, fine, and clean." The length of the beds should be determined according to the water source. Beds can be made 80-100 m long and 4.2-4.4 m wide; beds can also be made 40-50 m long and 4.2-4.4 m wide.

2.2 Seed Selection

Peel by hand and break apart the cloves, remove the garlic base plate and stem plate, and grade by large, medium, small, and central cloves; small cloves should be handled according to specific circumstances. Seed selection requirements are pure white with no red streaks, no wounds, no sugarification, and no glossy skin. In principle, each clove should weigh about 5 g. Seed size is the key to obtaining high yield.

2.3 Timely Sowing

Garlic should be sown at the right time. The planting time is from the end of White Dew to the beginning of Autumn Equinox (late September to early October), with a temperature of about 17°C. Before sowing, sun-dry the garlic cloves for 1-2 d.

2.4 Reasonable Close Planting

Generally, row spacing is 20 cm, plant spacing is 16-17 cm, and about 20,000 plants per 667 sq m. The method is to open furrows with a rake or furrow opener, with a furrow depth of about 5 cm, and after planting cover the garlic with about 1 cm of soil.

3 Field Management

3.1 Irrigation

Garlic has a relatively large water requirement, and generally needs to be watered 4 times during the entire growing period.

(1) Film-covering water: After garlic is sown, it should be watered promptly, thoroughly, and enough, without missing a single plant, with 100 cubic meters of water per 667 sq m. This watering both meets the needs of garlic planting and facilitates covering with plastic film.

(2) Strong seedling water: Generally watered around early April or when the soil temperature is above 15°C.

(3) Bolting water: Water with this as soon as the garlic scape just emerges.

(4) Bulb expansion water: Water with this immediately after pulling the garlic scapes.

3.2 Plastic Film Mulching

Plastic film mulching is the key to increasing garlic yield. It can raise soil temperature, accelerate organic matter decomposition, reduce water evaporation, and satisfy garlic's environmental needs. After watering for film covering, when the ground has slightly settled, cover with film using a mulching machine or by hand. Whichever method is used, the film must be pulled tight and the two sides pressed firmly to prevent the film from being lifted by strong winds in autumn and winter.

3.3 Releasing Seedlings

As soon as the garlic sprouts break through the soil, promptly poke holes in the plastic film so the seedlings are exposed outside the film. Generally, in the early morning or evening, when the temperature is low and the film has little elasticity, lightly pat the film with a new broom or lightly rake it with bamboo rake tines.

3.4 Manual Weeding

During the garlic growing period, the temperature is relatively low, and weed damage mainly occurs after the Spring Festival. Because plastic film is used, weeds are controlled manually. The method is to use a thick iron rod or 8 mm steel bar bent into a "7" shape to make a small hook, tear a small opening in the film, and remove small weed seedlings.

3.5 Pulling Garlic Scapes

When the upper part of the garlic scape begins to curl upward from below, it is the best time to pull the garlic scapes. The method is to gently pull by hand every day from 11 a.m. to 3 p.m.

4 Fertilization

The fertilization principle for green food garlic is to mainly use organic fertilizer, apply a small amount of chemical fertilizer according to a formula, mainly use base fertilizer, and use topdressing as a supplement.

4.1 Base Fertilizer

In late September, apply 5000 kg of high-quality farmyard manure (fully decomposed barnyard manure, compost, or cake fertilizer), 20 kg of urea, and 10 kg of potassium sulfate per 667 sq m. It is required to spread evenly, then deep-plow the field.

4.2 Topdressing

In early April of the second year, in combination with watering for strong seedlings, apply 10 kg of quick-acting fertilizer urea by flushing per 667 sq m. In mid-April, dissolve 0.5 kg of potassium dihydrogen phosphate in 50 kg of water and spray it per 667 sq m.

5 Pest and Disease Control

Because green food garlic cultivation mainly uses organic fertilizer, the plants have strong disease resistance, and in addition, the temperature during the garlic growing period is low, so garlic pests and diseases occur relatively lightly. The commonly occurring pests and diseases are leaf blight and garlic maggot.

5.1 Leaf Blight

Leaf blight is a major disease during garlic growth. When damage is severe, garlic does not easily bolt, thereby affecting garlic yield. The general control method is: in mid-April at the early stage of disease onset, use 100 g of 75% chlorothalonil wettable powder per 667 sq m, dilute with water, and spray once.

5.2 Garlic Maggot

Garlic maggot does not generally occur widely in most years. In plots where garlic maggot occurs relatively heavily, in combination with land preparation, when opening furrows for garlic planting, apply 40 kg of plant ash per 667 sq m into the furrows, which can effectively control the occurrence of garlic maggot. However, when garlic maggot damage is relatively severe, chemical control can be used. The control method is: in late April, use 100 mL of 50% phoxim emulsifiable concentrate per 667 sq m, dilute with water, and pour the solution toward the garlic roots.

6 Harvesting, Grading, Packaging, Storage, and Transportation

6.1 Harvesting

The garlic harvest season is generally in mid-to-late May, around Lesser Fullness. When garlic leaves turn yellow and the cloves protrude, it can be harvested. When harvesting, use a special tool - a garlic puller - and do not break or bruise the garlic. After harvesting, the garlic should be dried promptly so it dries thoroughly, while also preventing excessive sun exposure and sugarification. The usual method is: cover the garlic heads with garlic leaves and dry them in the field for 10 h, then cut off the garlic roots (when cutting, be sure to cut flat and clean, and never injure the garlic body), and place in a ventilated place to continue drying. When the garlic stalks are 80-90% dry, cut the garlic stalks 2 cm below the garlic heads, bag them, and place in a ventilated place to continue drying, but they must not be directly exposed to the sun. After garlic harvest, promptly remove the residual plastic film.

6.2 Grading

Thoroughly dried garlic heads should be graded according to size and quality. Green food garlic is divided by specification into special-grade garlic heads (transverse diameter ≥70 mm, stalk length ≤15 mm), first-grade garlic heads (transverse diameter ≥60 mm, stalk length ≤15 mm), second-grade garlic heads (transverse diameter ≥50 mm, stalk length ≤15 mm), and third-grade garlic heads (transverse diameter <50 mm, stalk length ≤15 mm); according to appearance and quality, it is divided into first class, second class, and third class.

6.3 Packaging

Green food garlic should be packaged separately according to specification and grade, with consistent unit weight and consistent size specifications. Packaging boxes or bags should be clean, dry, breathable, pollution-free, and odorless. The green food logo design should be standardized, and the packaging should indicate product name, variety, net content, place of origin, distribution unit, packaging date, etc.

6.4 Storage and Transportation

The green food garlic storage area should have obvious signs and be placed in a dedicated constant-temperature warehouse for storage. It is forbidden to store non-green food products and green food products together. Green food transportation should use dedicated transport tools, and before loading, they should be cleaned according to procedures to ensure that garlic products are not contaminated during transportation.