Watermelon is an annual summer fruit known for its sweet, refreshing flavor. Many gardeners prefer growing it at home to enjoy fresh, flavorful harvests. However, watermelon plants require proper care to grow successfully—especially when it comes to fertilization. If you want to learn more about fertilizing watermelon, keep reading:
How to Fertilize Watermelon
Watermelon plants are heavy feeders, and for best results, they should be fertilized regularly to encourage fruit development and improve disease resistance. Here are the key steps and tips for fertilizing watermelon:
- Add organic compost and mix it into the soil to a depth of 15 cm before planting the seeds. Compost improves soil structure, adds micronutrients, enhances water retention, and promotes healthy fruit formation.
- Once seedlings appear, apply a balanced general-purpose fertilizer such as 5-5-5 or 10-10-10 at a rate of 680 g per 9 m² of garden space.
- A liquid seaweed fertilizer may be used when the first leaves appear and again when the plants begin to flower.
- Apply nitrogen fertilizer again 30–60 days after planting. In this case, use a 0-0-33 fertilizer at a rate of 227 g per 15 m of watermelon row.
Tips for Fertilizing Watermelon
- Test the soil before fertilizing to determine its needs. If a soil test isn’t available, a 10-10-5 fertilizer can be used at a rate of 7 kg per 150 m². To reduce nitrogen burn, mix the fertilizer well into the top 15 cm of soil.
- Apply a layer of mulch or grass clippings (8–10 cm thick) around watermelon plants to improve moisture retention, suppress weeds, and slowly add nitrogen-rich organic matter to the soil.
- When applying granular fertilizers, avoid contact with the leaves and water thoroughly so the roots can absorb the nutrients easily.
- Both organic fertilizers (such as fish emulsion and alfalfa meal) and chemical fertilizers with high concentrations of nitrogen, phosphorus, and potassium can be used.
- Apply the correct amount of fertilizer—too much or too little can negatively affect fruit quality and overall yield.
- The best time to fertilize watermelon is when the plants are still young seedlings. Once the plant begins producing fruit, stop fertilizing to encourage the fruit to grow larger and sweeter.
- Fertilizing watermelon plants when they are older than 3 months can result in fruit developing a bitter taste.
What Fertilizers Can Be Used for Watermelon?
Here are some recommended fertilizers along with their NPK ratios:
- Espoma Garden Tone 3-4-4
- Organic Plant Magic Super Premium 6-5-5
- Jobe’s Organics Granular Fertilizer 4-4-4
- Dr. Earth Natural Wonder Fruit Fertilizer 5-5-2
