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Growing watermelons in high tunnels is an effective way to extend the growing season and produce ripe, sweet melons beyond the traditional outdoor growing period. High tunnels provide a controlled environment that protects plants from harsh weather, pests, and diseases, allowing for earlier planting and later harvesting.
Benefits of Growing Watermelons in High Tunnels
- Extended growing season due to controlled environment
- Protection from pests and harsh weather conditions
- Potential for higher yields and better fruit quality
- Ability to start plants earlier in spring and harvest later in fall
Choosing the Right Watermelon Varieties
- Early-maturing varieties such as ‘Sugar Baby’ or ‘Crimson Sweet’
- Compact or bush types suited for high tunnel space
- Varieties with good disease resistance
Preparing the High Tunnel
Ensure the high tunnel is well-ventilated and has adequate drainage. Prepare the soil by adding compost and organic matter to improve fertility. Conduct a soil test to adjust pH and nutrient levels accordingly, aiming for a pH of 6.0 to 6.8.
Planting Watermelons in High Tunnels
Start seeds indoors 2-4 weeks before the last expected frost date. Transplant seedlings into the high tunnel once the soil warms to at least 70°F (21°C). Space plants about 3-4 feet apart in rows that are 6-8 feet apart to allow for vine growth.
Soil Preparation and Planting
Plant seedlings at the same depth they were growing in their containers. Water thoroughly after planting. Mulch around the plants to retain soil moisture and suppress weeds.
Caring for Watermelon Plants in a High Tunnel
Regular watering is essential, especially during dry periods. Water deeply to encourage strong root development, aiming for about 1-2 inches per week. Use drip irrigation to keep foliage dry and reduce disease risk.
Fertilization
Apply a balanced fertilizer, such as 10-10-10, at planting time. Side-dress with additional nitrogen during the growing season to promote vine and fruit development.
Pest and Disease Management
Monitor regularly for pests like aphids, cucumber beetles, and squash bugs. Use integrated pest management strategies, including physical barriers and organic controls. Prevent diseases such as powdery mildew and fusarium wilt by ensuring good air circulation and crop rotation.
Harvesting Watermelons in a High Tunnel
Watermelons are ready to harvest when the tendril closest to the fruit turns brown and dries up, and the spot on the melon where it rests turns a dull yellow. Use a sharp knife or pruners to cut the fruit from the vine, leaving a few inches of stem attached.
Extending the Season
To further extend the season, consider using row covers, supplemental heating, or shade cloths during colder months. Proper ventilation and monitoring temperature and humidity help maintain optimal growing conditions inside the high tunnel.
Conclusion
Growing watermelons in high tunnels offers a practical solution for extending the harvest season and improving fruit quality. With proper planning, care, and management, gardeners and farmers can enjoy delicious watermelons well beyond the typical outdoor season, increasing productivity and market opportunities.