How to Grow Watermelon in Kentucky

5 Steps to Growing Watermelon

Choosing the Right Variety

Selecting the appropriate watermelon variety is crucial for successful cultivation in Kentucky's climate. Look for varieties that are well-adapted to the state's hot summers and resistant to common diseases.

Heat-Tolerant Varieties

Kentucky's summers can be scorching, with temperatures often soaring above 90°F. To thrive in such conditions, it's essential to choose heat-tolerant watermelon varieties. Some popular options include:

• Sugar Baby: A small, ice-box type melon with a sweet, crisp flesh and early maturity.
• Crimson Sweet: A large, oblong melon with a deep red flesh and excellent flavor.
• Charleston Gray: A large, gray-green melon with a sweet, red flesh and good disease resistance.

Disease-Resistant Varieties

Watermelons are susceptible to various fungal and bacterial diseases, which can significantly impact their growth and yield. To combat these issues, consider planting disease-resistant varieties, such as:

• Crimson Trio: Resistant to fusarium wilt and anthracnose.
• Honey Heart: Resistant to fusarium wilt and anthracnose.
• Sangria: Resistant to powdery mildew and anthracnose.

Site Selection and Soil Preparation

Choosing the right location and properly preparing the soil are essential steps in growing watermelons in Kentucky.

Watermelons require a warm, well-drained soil with a pH range of 6.0 to 6.8. Conduct a soil test to determine the nutrient levels and amend the soil accordingly. Incorporate aged compost or well-rotted manure to improve soil fertility and drainage.

Sun Exposure Requirements

Watermelons are sun-loving plants that require at least 8 hours of direct sunlight per day. Select a site that receives full sun exposure and is protected from strong winds, which can damage the vines.

Soil Testing and Amendments

Before planting, test your soil to determine its pH and nutrient levels. If the pH is too low (acidic), add agricultural lime to raise it. If the soil is deficient in nutrients, apply a balanced fertilizer or compost to enrich it.

Here's an example soil test report and the recommended amendments:

NutrientCurrent LevelDesired LevelAmendment

pH	5.5	6.0 – 6.8	Apply 50 lbs of agricultural lime per 1,000 sq ft
Nitrogen	Low	Medium	Apply 1 lb of 10-10-10 fertilizer per 100 sq ft
Phosphorus	Medium	Medium	No amendment needed
Potassium	Low	Medium	Apply 1 lb of 10-10-10 fertilizer per 100 sq ft

Raised Beds or Hills

Watermelons perform well when planted in raised beds or hills, which improve drainage and warm the soil faster in the spring. Construct hills or raised beds that are 8 to 12 inches high and 3 to 4 feet wide, spacing them 6 to 8 feet apart.

Planting and Care

Proper planting and care are essential for a successful watermelon crop in Kentucky.

• Sow seeds directly in the ground after the last spring frost, when the soil temperature reaches 70°F or above.
• Space seeds 1 to 2 inches deep and 2 to 3 feet apart in rows, or plant 4 to 6 seeds per hill, thinning to 2 or 3 plants later.
• Water the plants deeply and regularly, providing 1 to 2 inches of water per week.
• Fertilize with a balanced fertilizer or compost tea every 4 to 6 weeks during the growing season.
• Mulch around the plants to retain moisture and suppress weeds.

Planting Time and Spacing

In Kentucky, the ideal planting time for watermelons is late May to early June, after the last frost has passed and the soil has warmed up. Here are the recommended spacing guidelines:

• Plant seeds 1 to 2 inches deep and 2 to 3 feet apart in rows.
• Or, plant 4 to 6 seeds per hill, spacing hills 6 to 8 feet apart in all directions.
• After germination, thin the seedlings to leave the two or three strongest plants per hill.

Watering and Fertilizing

Watermelons have high water requirements, especially during fruit development. Aim to provide 1 to 2 inches of water per week, either through rainfall or irrigation. Water deeply and consistently, avoiding shallow watering, which can lead to shallow root systems.

For fertilization, apply a balanced fertilizer or compost tea every 4 to 6 weeks during the growing season. Follow the specific instructions on the fertilizer label for the correct application rates.

Mulching and Weed Control

Mulching is highly recommended for watermelon cultivation in Kentucky. It helps retain soil moisture, suppress weeds, and moderate soil temperatures. Apply a 2 to 4-inch layer of organic mulch, such as straw, leaves, or grass clippings, around the plants after they have become established.

In addition to mulching, regular weeding is essential to prevent competition for nutrients and water. Carefully remove weeds by hand or use a hoe to cultivate the soil shallowly around the plants.

Pollination and Fruit Set

Watermelons rely on insect pollination for successful fruit set. Understanding the pollination process and addressing potential issues can help ensure a bountiful harvest.

Watermelons have separate male and female flowers on the same plant. Male flowers appear first, followed by female flowers a week or two later. Bees and other pollinating insects transfer pollen from the male flowers to the female flowers, allowing fruit development.

Hand Pollination Techniques

In some cases, such as in greenhouses or during periods of inclement weather, hand pollination may be necessary to ensure adequate fruit set. To hand pollinate, follow these steps:

1. Identify the male and female flowers. Male flowers have a thin stem, while female flowers have a small, immature fruit (ovary) behind the flower.
2. Remove a freshly opened male flower and gently transfer the pollen from the anther to the stigma of the female flower.
3. Repeat this process with several female flowers to increase the chances of successful pollination.

Dealing with Poor Fruit Set

If you notice poor fruit set despite adequate pollination, several factors could be at play:

• High temperatures (above 95°F) during flowering can inhibit fruit set.
• Excessive nitrogen fertilization can promote excessive vine growth at the expense of fruit production.
• Inadequate water or drought stress can also lead to poor fruit set.

To improve fruit set, ensure proper watering and fertilization practices, and consider providing temporary shade during the hottest parts of the day when temperatures exceed 95°F.

Pest and Disease Management

Like any crop, watermelons are susceptible to various pests and diseases. Early detection and proper management strategies are crucial for maintaining a healthy crop.

• Monitor your plants regularly for signs of pests or disease.
• Practice crop rotation to prevent the buildup of soil-borne pathogens.
• Choose disease-resistant varieties when possible.
• Implement organic or chemical control methods as needed, following label instructions carefully.

Insect Pests

Common insect pests that can affect watermelons in Kentucky include:

• Cucumber beetles: These yellow and black striped beetles can transmit bacterial wilt and other diseases. Control methods include row covers, sticky traps, and insecticides.
• Aphids: These small, soft-bodied insects can transmit viruses and cause stunted growth. Introduce beneficial insects, use insecticidal soaps, or apply insecticides if necessary.
• Squash vine borers: These larvae tunnel into the vines, causing wilting and plant death. Monitoring and physical removal of larvae are recommended.

Fungal and Bacterial Diseases

Several fungal and bacterial diseases can impact watermelon growth and yield in Kentucky:

• Anthracnose: This fungal disease causes sunken lesions on leaves, stems, and fruits. Manage it through crop rotation, fungicides, and resistant varieties.
• Fusarium wilt: A soil-borne fungus that causes wilting and plant death. Plant resistant varieties and practice crop rotation.
• Bacterial fruit blotch.