Watermelons, known for their sweet, juicy texture, are a summer favorite that thrive in hot temperatures. They come in various sizes, from small 'Sugar Baby' melons to larger heirlooms like 'Black Diamond'. While they require ample space and consistent care, watermelons are relatively easy to grow, making them a rewarding project for gardeners of all levels.
- Common Names: Watermelons
- Scientific Name: Citrullus lanatus
- Plant Type: Annual, Edible, Vine
- Plant Height: 4-8 inches
- Growing Difficulty: Medium
- Growing Time: 70-100 days
- Bloom Time: Spring, Summer
- Temperature: Best in long warm summers
- Sunlight: Full Sun
- Soil pH: 6.0-8.0
- Watering Frequency: Keep soil moist but not soggy
- Plant Spacing: Space plants 2-3 feet apart
Different Methods to Grow Watermelon
Starting Seeds Indoors
Seeds are started indoors 2 to 3 weeks before the last frost date and transplanted into the garden after the soil has warmed.
- Pros: Allows for an earlier start in cooler climates, can result in an earlier harvest.
- Cons: Requires indoor space and care, risk of damaging seedlings during transplanting.
Direct Seeding Outdoors
Seeds are sown directly into the garden 1 to 2 weeks after the last frost date when the soil temperature is at least 65°F (18°C).
- Pros: Simpler process, no need for indoor space.
- Cons: Dependent on weather conditions, later harvest compared to starting indoors.
Using Young Plants from Nurseries
Young plants are bought from nurseries and planted in the garden after the risk of frost has passed.
- Pros: Easier and quicker, less risk of damaging roots.
- Cons: More expensive, limited variety compared to seeds.
Ideal Soil and Location Requirements
Watermelons thrive in loamy, well-drained soil with a pH between 6.0 and 7.5. They require full sun and ample space, ideally up to 20 square feet per plant, to accommodate their sprawling vines. Raised rows enhance drainage and warmth.
When to Plant Watermelon
Watermelons should be planted in spring or summer, after the last frost date. In cooler climates, start seeds indoors 2-3 weeks before the last frost and transplant them outdoors when the soil reaches 65°F. In warmer climates, sow seeds directly outdoors 1-2 weeks after the last frost.
Growing Watermelon Outdoors
The best method to grow watermelon outdoors is by sowing seeds directly into the soil or transplanting young plants from a nursery after the last frost date when the soil has warmed to at least 65°F (18°C). This method is the easiest because it avoids the complications of starting seeds indoors and transplanting them, which can be stressful for the plants. Direct sowing or using nursery plants ensures that the watermelons are planted in optimal conditions right from the start.
- Choose a sunny location. Watermelons need full sun to thrive, so pick a spot in your garden that gets at least 8 hours of sunlight daily.
- Prepare the soil. Amend the soil with aged manure, compost, or seaweed to enrich it. Ensure the soil is loamy, somewhat sandy, and well-drained with a pH between 6.0 and 7.5.
- Create mounds. Form mounds that are 8 to 10 inches tall and 10 to 12 inches across. This helps with drainage and keeps the soil warm.
- Plant the seeds. Sow seeds 1/2 to 1 inch deep into the mounds. Space the mounds 3 feet apart in rows that are 5 feet apart.
- Water the seeds. Use a watering can or hose attachment to moisten the soil without washing the seeds out. Keep the soil consistently moist during germination.
- Thin the seedlings. When the seedlings have two sets of true leaves, thin them to one seedling per mound to ensure they have enough space to grow.
- Fertilize monthly. Apply a higher phosphorous fertilizer (5-10-10) once a month after flower buds appear to support fruit development.
- Train the vines. Move the vines to desired locations before the fruit develops, ensuring they are no more than 2 to 3 feet long to manage space and air circulation.
- Support the fruits. Place a barrier, such as straw or a small board, between the ripening melon and the soil to prevent insect damage and rot.
- Harvest ripe melons. Look for signs such as thinning and drying of the stem and a pale yellow spot where the melon contacts the soil. Use a sharp hand pruner to cut the stem, leaving about 2 inches attached to the fruit.
Growing Watermelon Indoors
Growing watermelon indoors is not feasible due to their extensive space requirements and need for full sun. However, starting seeds indoors is a great way to get a head start on the growing season. Here’s a step-by-step guide for home gardeners:
- Start seeds indoors. Plant seeds in biodegradable pots 2 to 3 weeks before the last frost date.
- Use larger pots. Choose pots that allow for more root growth to minimize root disturbance during transplanting.
- Ensure proper soil temperature. Keep the soil temperature at least 65°F (18°C) for optimal germination.
- Water consistently. Keep the soil moist but not waterlogged, providing 1 to 2 inches of water per week.
- Harden off seedlings. Gradually expose seedlings to outdoor conditions for about a week before transplanting.
- Transplant carefully. Move seedlings to the garden 2 weeks after the last frost date or when the soil has warmed to at least 65°F (18°C).
- Choose a sunny location. Ensure the planting site gets at least 8 hours of sunlight daily.
- Prepare the soil. Amend the soil with aged manure, compost, or seaweed to enrich it. Ensure it is loamy, somewhat sandy, and well-drained with a pH between 6.0 and 7.5.
- Create mounds. Form mounds that are 8 to 10 inches tall and 10 to 12 inches across to help with drainage and warmth.
- Plant the seedlings. Space the mounds 3 feet apart in rows that are 5 feet apart. Place one seedling per mound.
- Fertilize monthly. Use a higher phosphorous fertilizer (5-10-10) once a month after flower buds appear to support fruit development.
- Train the vines. Move the vines to desired locations before the fruit develops, ensuring they are no more than 2 to 3 feet long to manage space and air circulation.
- Support the fruits. Place a barrier, such as straw or a small board, between the ripening melon and the soil to prevent insect damage and rot.
- Harvest ripe melons. Look for signs such as thinning and drying of the stem and a pale yellow spot where the melon contacts the soil. Use a sharp hand pruner to cut the stem, leaving about 2 inches attached to the fruit.
Watermelons can be grown in raised beds with specialized trellising to support the fruits. This method is ideal for small spaces, allowing the vines to climb while ensuring the fruits are well-supported.
Caring for Watermelon
- Watering: Watermelons need consistent moisture, especially from planting until the fruit begins to form. Aim for 1 to 2 inches of water per week. Water at the base of the vine in the morning to avoid wetting the leaves, which can lead to disease.
- Mulching: Use black plastic or straw mulch around the plants. This helps to warm the soil, suppress weeds, and keep the developing fruits off the ground, reducing the risk of rot and insect damage.
- Pest Management: Common pests include aphids, cucumber beetles, and squash vine borers. To protect your plants, cover them with row covers after transplanting and remove the covers when flowers appear to allow for pollination. Regularly inspect plants and remove any pests by hand.
- Fertilizing: Start with a nitrogen-rich fertilizer to encourage vine growth. Once the plants begin to flower, switch to a higher phosphorous fertilizer, such as 5-10-10, to support fruit development. Continue fertilizing monthly throughout the growing season.
- Harvesting: Watermelons are ready to harvest when the stem starts to thin and turn grayish-brown, and the spot where the melon touches the ground turns a pale yellow. Use a sharp knife or hand pruner to cut the stem, leaving about 2 inches attached to the fruit.
Common Challenges With Watermelon
Watermelons are generally considered easy to grow, especially in regions with long, warm summers. They thrive in full sun and loamy soil with a neutral pH. Starting seeds indoors can give you a head start, but direct seeding outdoors is also a viable option. In my experience, watermelons are a rewarding plant for both novice and experienced gardeners, offering a sweet, juicy payoff for your efforts.
However, growing watermelons does come with its challenges. They are susceptible to a variety of pests such as aphids, cucumber beetles, and squash vine borers. Diseases like fusarium wilt and blossom end rot can also pose problems. Additionally, watermelons require consistent moisture and ample space, which can be tricky to manage. Despite these hurdles, with proper care and attention, you can successfully grow delicious watermelons in your garden.
Safety of Watermelon for Pets
Watermelon is generally safe for cats, dogs, and other pets when given in moderation. However, avoid feeding them the seeds and rind, as these can cause digestive issues. If you suspect poisoning, contact the ASPCA's 24-hour hotline.
Frequently Asked Questions
How do I know when a watermelon is ripe and ready to harvest?
Look for signs such as the stem thinning and turning grayish-brown, and the spot where the melon touches the ground turning a pale yellow. These indicators suggest the watermelon is ripe and ready for harvest.
What is the best way to water watermelon plants?
Watermelons need consistent moisture, especially from planting until the fruit begins to form. Aim for 1 to 2 inches of water per week, watering at the base of the vine in the morning to avoid wetting the leaves, which can lead to disease.
Can I grow watermelons in a small garden?
Yes, you can grow watermelons in a small garden by using raised beds with specialized trellising to support the fruits. This method allows the vines to climb while ensuring the fruits are well-supported, making efficient use of limited space.
What should I do if my watermelon plants are affected by pests?
Common pests include aphids, cucumber beetles, and squash vine borers. To protect your plants, cover them with row covers after transplanting and remove the covers when flowers appear to allow for pollination. Regularly inspect plants and remove any pests by hand.
