Light requirements: Full sun.
Planting: Space 36 to 60 inches apart. (Read the stick tag that comes with the plant for specific spacing recommendations.)
Soil requirements: Provide well-drained, nutrient-rich soil that’s high in organic matter. Work at least 3 inches of organic matter into planting beds—more is better. Soil should be at least 70ºF at planting.
Water requirements: Keep soil consistently moist until fruits are about the size of a tennis ball. After that, water only when soil is dry. Avoid overhead watering to beat foliar diseases; use soaker hoses instead. About a week before fruits are ripe, water only if leaves wilt. Withholding water at this stage concentrates sugars in fruit.
Frost-fighting plan: Even a very light frost (31 to 33ºF) can kill watermelon vines. Use frost blankets or cold frames to protect vines and prolong the harvest season. To ensure fruits ripen before frost, remove any blossoms that start to develop within 50 days of your area’s average first frost date.
Common issues: Pests to watch out for include melon aphids, along with spotted and striped cucumber beetles. Fungal diseases such as alternaria leaf spot, gummy stem blight, anthracnose, downy mildew, and powdery mildew can attack plants.
Harvesting: Harvest when rind changes from bright to dull green, and the part that touches soil shifts from greenish white or straw yellow to rich, creamy yellow. Rap on the skin and listen for a low-pitched thud; tune your ear to the incorrect sound by rapping on a few fruits that aren’t ripe. Underripe fruits resonate with a high-pitched, tinny sound. Cut melons from the vine, leaving about an inch of stem attached to prevent rotting if they’ll sit before use.
Storage: Watermelons keeps 2 to 3 weeks unrefrigerated. Place in a cool area, such as a basement, to increase holding time. After cutting, refrigerate unused portions. If you have extra melon on hand, dice or cut the flesh into balls and freeze.
Sweet, juicy homegrown watermelons capture the magic of summer with explosive taste that puts store-bought melons to shame. Like their cantaloupe cousins, watermelons demand 2 to 3 months of heat to produce ripe fruit, which makes growing watermelons in northern regions challenging, but not impossible. By using plastic mulch to warm soil and floating row covers to trap warm air near plants, gardeners in any part of the country can experience the homegrown goodness of watermelons.
Nutritionists have found that watermelon should be in most people’s diets because of all the health-promoting vitamin C and antioxidants—including beta-carotene and lycopene—in every bite. These fruits combine great taste with excellent nutrition, with no cholesterol and nearly no fat—in other words, the perfect dessert.
Quick Guide to Growing Watermelon
- Plant watermelon from late spring to early summer, once soil temperatures reach 70° F or above.
- Space watermelon 3 to 5 feet apart in nutrient-rich, well-drained soil with a pH of 6.0 to 6.8.
- Give plants a fabulous start to the growing season by improving native soil with several inches of aged compost or other rich organic matter.
- Consistent water supply is critical to growing huge flavorful watermelon; install a soaker hose or drip irrigation for best results. Avoid wetting the leaves.
- Watermelons have huge appetites. Keep them well-fed with a continuous supply of nutrients by using a slow-release fertilizer regularly.
- Keep young melons off the ground with a bed of straw.
- Harvest watermelons when they turn from bright to dull green. They should sound hollow when you knock on them.