How to Grow Watermelons in Illinois

What Month do you Plant Watermelons or Sow Melon Seeds

Growing watermelons in Illinois can be a rewarding experience for gardeners and farmers alike. With the right varieties, soil preparation, and care, you can successfully cultivate these large, juicy fruits in the state's climate. This comprehensive guide will provide you with the essential steps to grow watermelons in Illinois, from selecting suitable varieties to harvesting and storing your bountiful crop.

Choosing the Right Watermelon Variety

One of the most crucial factors in growing watermelons in Illinois is selecting varieties that thrive in the state's growing conditions. Look for varieties that can withstand Illinois' warm summers and relatively short growing season.

Heat-Tolerant Varieties

Illinois summers can be hot and humid, making heat-tolerant watermelon varieties a necessity. Some excellent options include:

• Sugar Baby: A classic, small-sized watermelon with a sweet, crisp flesh and a short maturation period of 75-80 days.
• Crimson Sweet: A large, oblong watermelon with a deep red flesh and a high sugar content. It matures in 85-90 days.
• Millennium: A high-yielding, disease-resistant hybrid variety with a sweet, firm flesh and a maturation time of 90-100 days.

Disease-Resistant Varieties

In addition to heat tolerance, choosing disease-resistant watermelon varieties can help ensure a successful harvest. Consider the following options:

• Sangria: A fusarium wilt-resistant variety with a crisp, red flesh and a high sugar content. It matures in 90-95 days.
• Revolution: A hybrid watermelon resistant to anthracnose and fusarium wilt, with a sweet, bright red flesh. It takes 85-90 days to mature.
• Jade Star: A compact, disease-resistant variety that produces small, round watermelons with a crisp green flesh. It matures in 70-75 days.

Preparing the Soil for Watermelon Cultivation

Proper soil preparation is essential for growing healthy watermelon plants and maximizing yields. Watermelons thrive in well-drained, nutrient-rich soils with a pH between 6.0 and 6.8.

Soil Testing and Amendments

Before planting, test your soil to determine its nutrient levels and pH. Based on the test results, amend the soil with the necessary fertilizers, compost, or lime to achieve the desired pH and nutrient balance. Watermelons benefit from soils rich in organic matter, so consider incorporating aged manure or compost into the planting area.

Raised Beds or Hills

Watermelons perform best when grown in raised beds or hills. These elevated planting areas improve drainage, warm the soil more quickly in the spring, and provide adequate space for the vines to sprawl. Construct hills or raised beds that are 8-12 inches high and 4-6 feet wide, spacing them 6-8 feet apart to accommodate the spreading vines.

Planting Watermelon Seeds or Transplants

Once the soil is prepared, it's time to plant your watermelon seeds or transplants. Both methods have their advantages and drawbacks.

Direct Seeding vs. Transplanting

Direct seeding is a popular method for watermelon cultivation. It involves sowing seeds directly into the prepared hills or raised beds, typically 1-2 inches deep and 12-18 inches apart. This method eliminates the risk of transplant shock and allows the plants to establish a strong root system from the start.

Alternatively, you can start watermelon seeds indoors 3-4 weeks before the last expected frost date. Transplanting seedlings into the garden allows for an earlier harvest but requires careful handling to avoid damaging the roots.

Spacing and Depth Requirements

Proper spacing is crucial for watermelon plants to thrive and produce abundant fruit. When direct seeding, plant the seeds 1-2 inches deep and 12-18 inches apart within the hills or raised beds. If transplanting, space the seedlings 24-36 inches apart, allowing ample room for the vines to spread.

Ideal Planting Time in Illinois

In Illinois, the ideal time to plant watermelons is after the last expected frost date, typically between mid-May and early June. Watermelons require warm soil temperatures of at least 70°F (21°C) to germinate and grow efficiently. Monitor soil and air temperatures closely, and adjust your planting time accordingly.

Caring for Watermelon Plants

Proper care is essential for watermelon plants to thrive and produce high-quality fruit. Follow these guidelines for optimal growth and yield.

Watering Needs

Watermelons have high water requirements, especially during fruit development. Provide consistent moisture by watering deeply, applying 1-2 inches of water per week, depending on weather conditions. Avoid overhead watering, which can promote fungal diseases, and instead, use drip irrigation or soaker hoses.

Mulching and Weed Control

Mulching around watermelon plants helps retain soil moisture, suppress weeds, and regulate soil temperatures. Use organic mulches like straw, leaves, or grass clippings, applying a 3-4 inch layer around the plants, but not directly on the stems or vines.

Additionally, regular weeding is crucial to prevent competition for nutrients and water. Consider using a thick layer of mulch or applying a pre-emergent herbicide before the watermelon vines spread to minimize weed growth.

Fertilization and Nutrient Management

Watermelons are heavy feeders and benefit from regular fertilization. Apply a balanced fertilizer, such as 10-10-10 or 12-12-12, at the time of planting and again when the vines begin to run. Side-dress the plants with nitrogen-rich fertilizer, like ammonium nitrate or blood meal, when the fruits start to develop.

Foliar sprays with micronutrients, like boron or calcium, can also help prevent deficiencies and promote healthy fruit development.

Troubleshooting Common Problems

While watermelons are generally hardy plants, they can still face challenges from pests, diseases, and environmental stresses. Here are some common issues to watch out for and how to address them.

Pest and Disease Management

Several pests and diseases can affect watermelon plants, including:

• Aphids: Control these sap-sucking insects with insecticidal soaps or neem oil.
• Cucumber beetles: Apply row covers or use organic pesticides like pyrethrin or spinosad.
• Fusarium wilt: Grow resistant varieties and practice crop rotation.
• Powdery mildew: Improve air circulation and apply fungicides if necessary.

Regular monitoring and prompt action are essential for effective pest and disease management.

Environmental Stress Factors

Watermelons can be susceptible to environmental stresses, such as:

• Temperature extremes: Provide shade during heatwaves and protect plants from frost.
• Drought: Maintain consistent soil moisture with mulch and irrigation.
• Excessive rain: Improve drainage and avoid walking on waterlogged soil.

Addressing environmental stresses promptly can help minimize their impact on plant growth and fruit production.

Harvesting and Storing Watermelons

Proper harvesting and storage techniques are crucial for enjoying your watermelon crop to the fullest.

Determining Ripeness

Several indicators can help you determine when watermelons are ripe and ready for harvest:

• The underside (where the melon rests on the ground) turns from white to creamy yellow.
• The rind develops a dull, matte appearance and loses its glossy sheen.
• The tendril nearest the fruit stem turns brown and dries up.
• Thumping the melon produces a dull, hollow sound rather than a sharp, metallic one.

Harvesting Techniques

To harvest watermelons, use a sharp knife or pruning shears to cut the fruit from the vine, leaving 2-3 inches of stem attached. Avoid pulling or twisting the melon, as this can damage the fruit and vines.

Handle watermelons gently to prevent bruising or splitting, and harvest during the coolest part of the day to minimize moisture loss.

Proper Storage Conditions

Watermelons can be stored for several weeks if handled and stored properly:

• Avoid washing watermelons before storage, as excess moisture can promote spoilage.
• Store watermelons at room temperature (around 70°F or 21°C) for up to two weeks.
• For longer storage, place watermelons in a cool, dry area (55-60°F or 13-16°C) with good air circulation.
• Avoid stacking watermelons, as this can cause bruising and premature spoilage.