Water and Fertilizer Management for Autumn-Planted Garlic

Garlic is a beloved ingredient, prized not only for its distinctive flavor but also for its antibacterial properties that help prevent colds, with regular consumption even offering some cancer‑preventive benefits. In northern regions, it’s often enjoyed raw, while in the south it’s typically used as a seasoning to enhance the aroma of dishes. In recent years, an increasing number of farmers have recognized garlic’s economic value and have begun cultivating it. So, when growing garlic, how should autumn‑planted garlic be top‑dressed? And what are the key practices for managing its water and fertilizer needs? Let’s take a look!

How should topdressing be applied to garlic sown in autumn?

1. Seedling‑boosting fertilizer: After the garlic seedlings have uniformly emerged, apply a foliar spray of ChaoSu Nitrogen‑Potassium at 5 liters per mu to promote vigorous growth. Avoid using ammonium bicarbonate to prevent scorching of the young plants. At the same time, apply either the microbial biofertilizer GuiGenDaoDi or a soil‑borne disease‑suppressing agent at 10–20 liters per mu to help prevent soil‑borne diseases and enhance the seedlings’ disease resistance.

2. Bulb‑tiller fertilizer: After the seed garlic has produced a rotted mother bulb, flower buds and scale buds begin to differentiate, entering the stem‑elongation phase. During this period, old roots senesce while new roots proliferate; at the same time, stems, leaves, and garlic scapes elongate rapidly, and the bulb starts to swell slowly. Consequently, nutrient demand is high, so apply a heavy dose of quick‑acting nitrogen‑potassium fertilizer (a compound fertilizer is preferable, such as Active Humic Acid 25‑10‑10S or 22‑8‑10S) at 15–20 kg per mu, supplemented with JunChongFeng and humic acid soluble powder. Apply these products about two weeks before the scape emerges—when you can observe a short scape at the base of the pseudostem—to meet nutritional needs, promote root development, enhance disease resistance, and ensure rapid scape emergence and vigorous growth.

3. Bulb‑enlarging fertilizer: For early‑maturing and early‑mid‑maturing varieties, since temperatures remain relatively low during bulb enlargement, the bulbing period tends to be longer. To promote bulb growth, apply a quick‑acting nitrogen‑potassium fertilizer before harvesting the garlic scapes. For example, use 10–15 kg per mu of humic acid–nitrogen–sulfur compound fertilizer with an N:P₂O₅:K₂O ratio of 15‑5‑20 or 15‑5‑23. If using urea alone, about 5 kg per mu is sufficient; avoid over‑fertilizing, as this can cause the already formed bulb‑cloves to re‑green and produce new leaves, thereby depleting the nutrients stored in the cloves. Topdressing should be applied prior to scape harvest; once the scapes are removed, abundant nutrients will support bulb enlargement. Applying topdressing after scape harvest may lead to excessive vegetative growth and reduced yield. In fields with naturally fertile soil and robust, dark‑green foliage, less bulb‑enlarging fertilizer is needed. For mid‑ and late‑maturing varieties, which bolt later and experience higher temperatures, bulbs are typically harvested about 20–25 days after scape removal; therefore, additional bulb‑enlarging topdressing can often be omitted.

4. Foliar Fertilization: During the green-up stage, apply Heizefeng foliar spray once to promote leaf growth and enhance photosynthetic capacity. During the bulb‑formation stage, apply Nongda Huangjinlu, Zhuangkeli, or similar products 2–3 times to supply nutrients, extend the functional period of the leaves, prevent malformed bulbs, and improve garlic quality.

How should autumn-sown garlic be watered?

1. Uniform Seedling Stage: Typically, seedlings emerge uniformly within one week of sowing. After applying a topdressing fertilizer for uniformity, if the soil is relatively dry, irrigate once to promote seedling growth.

2. Early Seedling Stage: The seedling stage is a critical period for the differentiation and development of garlic’s vegetative organs. Following emergence, garlic enters the early seedling growth phase; irrigation should be applied as needed in accordance with regional rainfall patterns, and effective drainage measures should be implemented.

3. Mid-to-late seedling stage: This phase is marked by the period from before winter dormancy to the end of bulb‑maturation. It is relatively long and represents a critical period for the garlic’s vegetative growth. Before winter, rainfall in many regions has already declined significantly, leaving the soil rather dry; a single irrigation is advisable at this time. After winter, as temperatures gradually rise, the seedlings resume vigorous growth, necessitating timely watering to promote leaf development and increase pseudostem thickness.

4. Bolting Stage: All the leaves differentiated during the seedling stage have fully unfolded, leaf area has reached its peak, and the root system has expanded considerably. Bulb‑scape growth accelerates during this period, which is when fertilizer and water requirements are highest; therefore, after applying the topdressing fertilizer for bolting, irrigate promptly to promote scape development. Following the emergence of the scape, continue watering regularly to encourage vigorous growth, ceasing irrigation 2–3 days before harvest to facilitate storage and transportation.

5. Bulb‑enlargement stage: Begin irrigating 2–3 days after harvesting the garlic scapes to promote rapid bulb enlargement and weight gain. Stop watering five days before harvest to curb vegetative growth and facilitate the accelerated translocation of assimilates from the leaves to the bulbs.