What fertilizer is the best for growing watermelons

The optimal fertilizer selection for watermelon cultivation needs to be adjusted according to the growth stage. Nitrogen fertilizer is mainly used to promote stem and leaf growth during the seedling stage, and phosphorus and potassium fertilizers are added during the flowering and fruiting stages to improve fruit quality. Common fertilizers include decomposed organic fertilizers, urea, superphosphate, potassium sulfate, compound fertilizers, etc.

1. Fermented organic fertilizer

Fermented farm manure or commercial organic fertilizer can improve soil structure and enhance water and fertilizer retention capacity. During the base fertilizer stage, 2000-3000 kilograms should be applied per acre, and complete fermentation should be carried out to avoid burning the roots. Organic fertilizer contains trace elements, which can prevent watermelon deficiency and reduce soil compaction when used for a long time.

2. Urea

Nitrogen fertilizer is crucial for the growth of watermelon seedlings, and urea can be applied 7-10 days after transplantation. The dosage per acre should be controlled at 10-15 kilograms, as excessive use can lead to excessive growth and affect fruit setting. Sandy soil should be applied in stages to avoid nutrient loss. After fertilization, timely watering should be done to promote absorption.

3. Calcium superphosphate

Applying phosphorus fertilizer 20 days before flowering can promote flower bud differentiation, with a base application of 30-40 kilograms per acre. Phosphorus has poor mobility and should be concentrated in the root dense area for application. Mixing with organic fertilizers can reduce soil fixation, and acidic soils need to be adjusted for pH with lime.

4. Potassium sulfate

The amount of potassium required during the fruit swelling period significantly increases, and 15-20 kilograms of potassium sulfate should be applied per acre after fruit setting. Potassium fertilizer can increase sugar accumulation, improve fruit texture, and enhance disease resistance. Avoid mixing with calcium containing fertilizers. Sandy loam soil should be reapplied in two stages to prevent leaching loss.

5. Compound fertilizer

Balanced compound fertilizer is suitable for various growth stages, with a recommended nitrogen phosphorus potassium ratio of 20-10-10 during the seedling stage and 15-15-30 during the flowering and fruiting stage. Water soluble fertilizers can be applied through drip irrigation systems, with a utilization rate of up to twice that of ordinary fertilizers. Choose a low chlorine formula to prevent excessive chloride ions from affecting quality. Watermelon fertilization should adhere to the principle of small amounts and multiple times, and adjust the formula based on soil testing. During the fruit development period, foliar application of calcium and magnesium fertilizer can be used to prevent navel rot, and fertilization should be stopped 15 days before harvest. Suggest crop rotation of leguminous green manure to improve soil microecology, and increase the use of bio microbial fertilizers in continuous cropping plots. Pay attention to the interval between fertilizers and pesticides, avoid fertilizing at noon in hot weather, and promptly replenish lost nutrients after rain.