Guide to Growing Watermelons
When to Plant
Watermelons need warmth, so:
- Start seeds indoors 3-4 weeks before the last frost if you have a short growing season.
- Direct sow seeds outdoors once the soil has warmed up to 70°F and all frost danger has passed (usually late spring to early summer).
Prepare the Soil
Watermelons love fertile, well-draining soil:
- Aim for a loamy soil type with a pH of 6.0-6.8.
- Improve your soil by mixing in compost or well-rotted manure.
- If your soil is heavy or clay-like, consider adding organic matter to help with drainage.
Planting
- Transplanting: Be sure to not disturb the roots. They are sensitive and stress easily.
- Spacing: Watermelon vines spread out, so space your plants about 36-42 inches apart in rows that are 6-8 feet apart.
- Planting Depth: Plant seeds 1/2 inch deep. If you’re starting with seedlings, space them 12-18 inches apart.
- Vine Setup: Watermelons are sprawling plants, so make sure they have plenty of space to spread out, or consider training them on a trellis if you’re growing small varieties.
Watering
- Watermelons need consistent moisture for proper growth, especially while the fruit is developing.
- Water deeply but avoid overhead watering. Instead, use drip irrigation or a soaker hose to keep the foliage dry.
- Aim for 1-1.5 inches of water per week, increasing during hot periods but decreasing as melons mature.
Mulching
- Use a layer of straw, grass clippings, or black plastic mulch around your plants to help keep the soil moist, suppress weeds, and maintain consistent soil temperature.
Fertilizing
- Watermelons are heavy feeders. Apply a balanced fertilizer when planting, then use a phosphorus- and potassium-heavy fertilizer once the vines begin to spread and fruit develops.
- Consider using organic fertilizers like compost or well-rotted manure.
Pruning and Trellising (Optional)
- Pruning isn’t always necessary, but cutting back excess vines can help improve air circulation and focus energy on the main fruits.
- Remove any side shoots and yellowing leaves to keep the plant healthy.
- Small ice box-type watermelons can be trellised to save space. Be sure to sling the fruit until they are ready to be harvested.
Dealing with Pests and Diseases
- Watch for pests like aphids, squash bugs, and cucumber beetles. Use insecticidal soap or neem oil as needed.
- Keep an eye out for fungal diseases like powdery mildew. Ensure proper spacing for air circulation and avoid overhead watering to reduce the risk.
Pollination
Watermelons are insect-pollinated, so you’ll need bees or other pollinators to help your plants produce fruit. If your garden has low bee activity, you can hand-pollinate by gently transferring pollen from the male flowers to the female flowers using a small paintbrush.
Harvesting
- Watermelons are typically ready to harvest when the tendril closest to the fruit turns brown and dry, and the bottom of the melon (where it touches the ground) turns yellow.
- Another way to check ripeness is to tap the melon—if it sounds hollow, it’s likely ripe.
- Cut the melon from the vine, leaving about a 2-inch stem.
Storage
- Whole melons: Store them in a cool, dry place (not in the fridge). They can last about 1-2 weeks at room temperature.
- Sliced melons: Keep them in the refrigerator for up to 5 days, wrapped in plastic or stored in an airtight container.
Bonus Tips for Success:
- Temperature: Watermelons thrive in warm soil and need warm nights (above 60°F/15°C) to grow well.
- Spacing: Give your watermelons plenty of space to spread out; crowded vines can lead to smaller fruit and slower growth.
- Companion Planting: Try planting marigolds or nasturtiums near your watermelon plants to help repel pests.
With patience and care, you’ll be enjoying your sweet, homegrown watermelons by mid-to-late summer. Happy gardening!🌱🍉