What are the best times for topdressing garlic, which fertilizers to choose, and what are the taboos?

In years when garlic market prices keep climbing, growing garlic has become popular. Many farmer friends want to plant or plant more garlic to increase their income. However, when growing garlic, you must pay attention to the degree of fertilization. So, when is the best time for topdressing garlic? What fertilizer should be applied to garlic? What should be noted when fertilizing garlic? Let's take a look below!

Although garlic seedlings have nutrition from the seed cloves during the seedling growth period, timely topdressing is still necessary to promote seedling growth and increase the plant's nutritional area. Because the garlic root system has a weak ability to absorb water and fertilizer, quick-acting fertilizer should be applied as topdressing to avoid nutrient deficiency that causes yellowing leaf tips. Garlic is generally topdressed 3 to 4 times.

Topdressing periods for garlic: seedling-promoting fertilizer

After the garlic seedlings have all emerged, apply one light application of diluted human manure and urine to promote the seedlings. Do not apply ammonium bicarbonate, to prevent burning the seedlings.

Topdressing periods for garlic: vigorous growth fertilizer

60 to 80 days after sowing, heavily apply once rotted human and livestock manure plus chemical fertilizer: 1000 to 1500 kg of manure per mu, 10 kg of ammonium sulfate, and 5 kg of potassium sulfate or potassium chloride. For early-maturing varieties, topdress early; for mid- and late-maturing varieties, topdress later, so as to promote strong seedling growth and thick, sturdy stems and leaves, and to have few or no yellow tips by the time the mother clove rots.

Topdressing periods for garlic: scape-bearing fertilizer

After the seed garlic mother clove rots, flower buds and bulbils differentiate one after another and enter the flower stalk elongation stage. In this period the old roots age, a large number of new roots emerge, and at the same time the stems and leaves and garlic scapes also elongate rapidly, and the garlic bulb also begins to swell slowly, so nutrient demand is high. A heavy application of quick-acting potassium and nitrogen fertilizer (compound fertilizer is better) of 10 to 15 kg should be applied about half a month before the tail appears (you can peel back the seedling to observe the short scape at the lower part of the pseudostem) to meet the demand and promote fast scape emergence and vigorous growth.

Topdressing periods for garlic: bulb-swelling fertilizer

For early-maturing and early mid-maturing varieties, because the temperature is not yet high when the garlic bulb swells, the bulb-swelling period is correspondingly longer. To promote bulb enlargement, quick-acting nitrogen and potassium fertilizer must be applied before harvesting the garlic scapes. For example, apply 5 to 10 kg of nitrogen-potassium compound fertilizer per mu; if urea alone is applied, about 5 kg is enough. Do not apply too much, otherwise it will cause the young sprouts of the already-formed garlic cloves to turn green and grow leaves again, consuming the nutrients of the garlic cloves.

Topdressing periods for garlic: before harvesting garlic scapes

Topdressing should be done before harvesting the garlic scapes, so that after the scapes are harvested there are abundant nutrients to promote bulb swelling. If topdressing is done after harvesting the scapes, it easily leads to the plants staying green and reducing yield. If the field soil is fairly fertile and the garlic leaves are thick and dark in color, the bulb-swelling fertilizer may be omitted. For mid- and late-maturing varieties, because scape emergence is late and temperatures are higher, garlic is generally harvested about 20 to 25 days after scape harvest, so the bulb-swelling fertilizer may also be omitted.

What fertilizer is good to apply to garlic

Throughout the whole growth period, according to the fertilizer requirements and growth of garlic, garlic with garlic bulbs and garlic scapes as the target products generally needs 2-3 topdressings. The first is at the mother-clove degeneration stage (4-5 leaves), mainly N fertilizer, applying 15-20 kg of urea per mu; the second is at the bulb swelling stage (9-10 leaves), that is, when the garlic scape is about to show its bract, apply a heavy application once, with 10-15 kg of urea per mu and 30-40 kg of potassium sulfate compound fertilizer (15:15:15); the third is when about 50% of scapes have been harvested, apply 15-20 kg per mu of potassium sulfate compound fertilizer (15:15:15). Garlic with garlic sprouts as the target product is only given the mother-clove degeneration fertilizer, and topdressing is prohibited 30 days before harvesting the green garlic sprouts. Each fertilization should be carried out together with irrigation.

In addition, in early April of the second year of garlic cultivation, together with watering for strong seedlings, apply 10 kg of quick-acting urea fertilizer 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.

Taboos in garlic fertilization

Garlic is a fertilizer-tolerant crop. On the basis of applying sufficient base fertilizer, topdressing is still needed in spring. For high-yield fields, the total amount of topdressing should be controlled at 12.5 kg of pure nitrogen and 5 kg of potassium. In fertilization, one must grasp that the period of vigorous nutrient growth (early to mid-April) is the period of maximum nitrogen fertilizer efficiency, the garlic bulb swelling period (Grain Rain? Start of Summer) is the period of maximum potassium fertilizer efficiency, and the nutrient required during the leaf formation period is mainly nitrogen; the earlier the nitrogen deficiency, the greater the yield reduction. During the garlic bulb swelling period, potassium deficiency appearing in the early stage has little effect, while appearing in the later stage has a great effect. The garlic scape elongation period is the period of maximum absorption of nitrogen, phosphorus, and potassium nutrients.

Garlic is a sulfur-loving crop. Allicin is mainly a disulfide-based compound. Most of the protein in garlic contains sulfur, and sulfur plays an important role in improving garlic quality. At the same time, studies show that only when the fertilizer N:S ratio is close to the optimal value can the nitrogen and sulfur absorbed by the plant be used most effectively. The N:S ratio in garlic is roughly 12:1. The utilization rate of sulfur in calcareous soils in the north is 2%?3%, and it is easily fixed as calcium sulfate, while the nitrogen utilization rate is 30%?35%. The optimal N:S is 4:5. Sulfur cannot be reused within the garlic plant, so sulfur must be supplemented in the middle growth stage to maximize the fertilizer effect. According to garlic's demand for nitrogen and sulfur, choose 40% nitrogen-sulfur fertilizer (N≥17.5%, S≥22.5%). Its fertilizer effect combines long-lasting and quick-acting effects, and the fulvic acid it contains plays an important role in promoting garlic root growth, improving disease resistance and fertilizer utilization, and can achieve the purpose of combining root promotion and root nourishment, avoiding premature aging, and increasing yield.

Supplementary application of green-returning fertilizer: after the garlic turns green, during rainy or snowy weather, broadcast 15/20 kg of 40% nitrogen-sulfur fertilizer per mu.

Heavy application of seedling-promoting fertilizer: in early April, apply 20/30 kg of 40% nitrogen-sulfur fertilizer per mu to meet the garlic's demand for nitrogen and sulfur during vigorous growth.

Apply bulb-promoting fertilizer well: when the garlic scape shows its tassel, flush-apply 15/20 kg of high-nitrogen, high-potassium fertilizer with water to accelerate garlic bulb swelling.