Foliar Spraying Techniques For Vegetable Fertilizers

Applying foliar fertilizer to vegetables is efficient, fast-acting, and boosts both yield and income. However, achieving good results requires mastering the proper application techniques and timing, as well as selecting the right type of fertilizer for the specific vegetable.

For leafy vegetables such as Chinese cabbage, celery, and spinach, urea and ammonium sulfate are the preferred fertilizers. The concentration should be kept below 2% for urea and below 1.5% for ammonium sulfate. Applications should generally be made at 10-day intervals; adding edible vinegar (diluted 500-fold) to the mixture can significantly enhance effectiveness.

For fruiting vegetables such as tomatoes, peppers, eggplants, and various melons and squashes, nutrient requirements for nitrogen, phosphorus, and potassium are relatively balanced; therefore, a compound fertilizer containing all three elements should be used. A mixture of 1–2% urea and 0.3–0.4% potassium dihydrogen phosphate can be prepared and applied. Generally, one application during the early growth stage and another during the late growth stage are sufficient.

For root and bulb vegetables such as garlic, onions, and radishes, which have a high demand for phosphorus and potassium, a mixture of 0.3% potassium dihydrogen phosphate and a 10% wood ash extract is recommended for foliar application, repeated 3–4 times per growing season.

Foliar fertilizer application should be carried out on sunny afternoons when the sunlight is not intense, or on overcast days. Approximately 40 kilograms of diluted fertilizer solution should be applied per mu (approx. 0.067 hectares) per session, ensuring the leaf surfaces are thoroughly wetted. Supplementing with appropriate amounts of micronutrients based on the specific needs of the vegetable can further increase yields and value, but care must be taken to avoid excessive concentrations. Crucially, acidic and alkaline fertilizers must not be mixed during application.