Two-crop Double-season Garlic Cultivation Techniques

I. What is two-crop (double-season) garlic. So-called two-crop (double-season) garlic means planting one season of early green garlic and one season of plastic-film garlic (also called harvest garlic, harvested for scapes and bulbs) within the year.

II. Benefits of two-crop garlic

1. It can effectively raise land utilization and realize a "three plantings, three harvests" or "four plantings, four harvests" cropping system in one year, namely "corn → green garlic → harvest garlic" or "corn → watermelon or winter melon → green garlic → harvest garlic". Every year 4-5 days before the "Qingming" solar term, plant 2 rows of corn along the edge rows of the garlic (planting waxy fresh corn is best), and leave the corn stalks to cover the garlic; interplant early watermelon or winter melon in the wide rows of the garlic (harvest garlic) (watermelon or winter melon is grown by the seedling transplanting method), and harvest garlic bulbs in batches while the watermelon or winter melon grows; plant green garlic around mid-July, and lift and market the garlic from late September to early October; plant plastic-film harvest garlic in mid-to-late October.

2. Two-crop garlic increases income markedly. According to a survey of growers in Yuhua Town, Dafeng City, the per-mu output value of two-crop garlic is 3800-4400 yuan, an increase of 52-46.6% and 111.1% respectively over single-season green garlic at 2500-3000 yuan and single-season harvest garlic at 1800 yuan; the per-mu net income is 2300-2900 yuan, an increase of 53.3-45% and 76.9% respectively over single-season green garlic at 1500-2000 yuan and single-season harvest garlic at 1300 yuan.

III. Key points of two-crop garlic cultivation techniques

1. Choose high-quality, high-yield, strong-spring varieties with strong growth. In the Dafeng area, "Ershuizao" is generally chosen as the main green garlic variety.

2. Do a good job of seed treatment and strive for early sowing. This is the key technique for the success or failure of early green garlic cultivation. Garlic growers in Yuhua generally adopt the method of cold-storing seed garlic to treat garlic seed. That is, split the garlic bulbs into cloves, put them into a constant-temperature fresh-keeping store 10-15 days before sowing, and keep them at about 0°C for 10-15 days (no more than 20 days at most) to break the dormancy period of the seed garlic. The cold-treatment time differs among different garlic seeds, and this point must be carefully grasped in production. If the time is too short, it will not break the dormancy of the seed garlic; if the time is too long, the seed garlic will develop faster after emergence, vegetative growth will be inhibited, and this is unfavorable for high yield of green garlic. Green garlic should be sown as early as possible, generally around the "Dashu" solar term. If there is vacant land, sowing can be advanced to mid-July.

3. Increase sowing amount and raise density. Early green garlic has a short growth period and small individual growth, so the seed amount should be appropriately increased to raise density. Generally the row spacing is 12-15 cm, the plant spacing is 1.5-3 cm, and 12,000-15,000 garlic cloves are sown per mu.

4. Harvest in time and free the land for sowing harvest garlic. The growth period of early green garlic is generally 70-80 days, and it can be lifted and marketed by late September. However, in September and October the environmental conditions such as light and temperature are good, and this is exactly the period of vigorous growth for green garlic; growing 1 more day in the field makes a difference in yield. Therefore, garlic should be lifted according to the principle of "guaranteeing the season, striving for benefits", but harvesting must be completed by October 25 at the latest.

Harvest garlic (plastic-film garlic) is mainly grown for garlic scapes and bulbs. Because its sowing time is delayed by 15-30 days compared with conventional cultivation, the bolting time of the garlic is correspondingly 7-10 days later; therefore, late-maturing varieties should be chosen. The main cultivation technical measures for harvest garlic are: First, apply sufficient base fertilizer and promote growth with fertilizer. "Three fertilizers" should be applied together, namely per mu apply 1000-1500 kg of organic fertilizer (sheep, pig, poultry, human manure), about 50 kg of garlic-specific compound fertilizer, and about 1500 kg of the surface fertilizer from the previous crop cover (corn stalks, wheat straw) as base fertilizer; Second, seize the time to sow and sow early at the right time. Make sure that as soon as one plot of previous-crop early green garlic leaves the field, that plot is prepared and sown, narrowing the sowing-period gap with conventional garlic as much as possible, with special emphasis that the latest sowing period is the end of October; Third, cover with film to raise temperature and strive for early seedlings. Generally, after sowing and before emergence, cover with ultra-thin plastic film at 2-2.5 kg per mu; it can be directly pierced by the garlic sprouts and does not need manual film breaking. In warm winters, the film may be omitted, and fertilizer and water methods can be used to regulate garlic growth; Fourth, pay attention to applying more reviving fertilizer and heavily applying scape fertilizer. Each time 12-15 kg of urea can be applied per mu.

IV. Several problems to note in two-crop garlic cultivation

First, prevent secondary growth (branching) of plastic-film garlic. The cause of secondary growth in garlic is excessively high accumulated temperature before winter, so whether to cover with plastic film should be decided according to weather forecasts; Second, prevent and control garlic diseases. Common garlic diseases include leaf blight and heart rot, and the crux is continuous cropping for many years. Therefore, two-crop garlic should be planted on new plots with a changed crop, and continuous cropping should be avoided as much as possible.