Watermelon Fertilizer Guide: 10 Steps to Bumper Crops

Watermelon Fertilizer Requirements

Watermelons are heavy feeders that require a balanced diet of nitrogen, phosphorus, and potassium. According to the University of Florida, watermelons need approximately:

• 120 lbs/acre of nitrogen
• 60 lbs/acre of phosphorus
• 180 lbs/acre of potassium

[Image of a watermelon field with healthy vines and large fruits]

Nutrient Ratio

The ideal nutrient ratio for watermelons is 1:2:3 (N:P:K). This ratio provides ample nitrogen for vegetative growth, phosphorus for root development, and potassium for fruit production.

Types of Watermelon Fertilizers

There are two main types of watermelon fertilizers: organic and inorganic.

• Organic fertilizers: Derived from natural sources such as manure, compost, and fish emulsion. They release nutrients slowly over time and improve soil health.
• Inorganic fertilizers: Synthesized from chemical compounds. They provide a quick burst of nutrients but can deplete soil fertility if overused.

10-Step Watermelon Fertilizer Program

Follow these steps for optimal watermelon fertilization:

1. Pre-Planting: Apply 10-10-10 fertilizer at a rate of 1000 lbs/acre and incorporate into the soil.
2. Transplanting: Fertilize with a balanced liquid fertilizer at a rate of 1 gal/acre.
3. 2-3 Weeks After Transplanting: Apply 500 lbs/acre of 10-10-10 fertilizer.
4. 4-6 Weeks After Transplanting: Fertilize with 300 lbs/acre of calcium nitrate.
5. 6-8 Weeks After Transplanting: Apply 250 lbs/acre of 10-10-10 fertilizer.
6. 10-12 Weeks After Transplanting: Fertilize with 150 lbs/acre of potassium nitrate.
7. 14-16 Weeks After Transplanting: Apply 100 lbs/acre of calcium nitrate.
8. 18-20 Weeks After Transplanting: Fertilize with 50 lbs/acre of 10-10-10 fertilizer.
9. 22-24 Weeks After Transplanting: Apply 25 lbs/acre of potassium nitrate.
10. Harvest: Fertilize with a high-phosphorus fertilizer to promote fruit ripening.

Watermelon Fertilizer Calculation

To determine the amount of fertilizer needed, use the following formula:

Fertilizer amount (lbs/acre) = Nutrient requirement (lbs/acre) / Fertilizer analysis (%) * 100

For example, to calculate the amount of 10-10-10 fertilizer needed to meet the nitrogen requirement of 120 lbs/acre:

Fertilizer amount = 120 / 10 * 100 = 1200 lbs/acre

Tips and Tricks for Watermelon Fertilization

• Use a soil test to determine the nutrient needs of your soil.
• Fertilize according to the specific nutritional requirements of your watermelon variety.
• Apply fertilizers in split applications to prevent nutrient burn.
• Watermelons prefer slightly acidic soil (pH 5.8-6.5).
• Boron deficiency can lead to poor fruit set. Apply borax to the soil at a rate of 1 lb/acre if necessary.
• Avoid overfertilizing, as this can damage the vines and reduce yields.

Common Mistakes to Avoid

• Applying too much nitrogen at once, which can cause excessive vine growth and reduce fruit production.
• Using fertilizers with high levels of chlorine, which can damage watermelon plants.
• Fertilizing too early, which can encourage early fruit set and poor quality fruits.
• Fertilizing too late, which can result in pale, low-yield watermelons.
• Not watering deeply after fertilization, which can prevent nutrients from reaching the roots.

Innovative Applications for Watermelon Fertilization

• Fertigation: Injecting fertilizer directly into the irrigation water. This method provides a controlled and efficient way to deliver nutrients to the plants.
• Foliar Feeding: Spraying liquid fertilizers directly onto the leaves. This method can be used to correct nutrient deficiencies quickly, but it is less effective than soil fertilization.

Tables for Quick Reference

Table 1: Watermelon Fertilizer Schedule

Table 2: Watermelon Nutrient Requirements

Table 3: Types of Watermelon Fertilizers

Table 4: Tips and Tricks for Watermelon Fertilization