How to Grow Watermelon
Citrullus lanatus
Citrullus lanatus produces juicy, sweet fruit that refreshes summer gardens. Gardeners grow these vigorous vines for their high water content and vibrant flavors, making them a staple in warm-season plots where space allows for sprawling growth.
📷 Wikipedia: WatermelonStarting Watermelon: indoors or direct sow?
🌾 Sow directly in the garden — Watermelon is not usually started indoors.
Direct sow seeds outdoors only after the last frost date once soil has warmed sufficiently, as cold snaps will kill this sensitive warm-season crop.
Soil, care & harvest
Prepare loose, well-draining soil with a pH between 6.0 and 6.8 to ensure optimal root development. As a warm-season crop, you must wait until after the last frost when soil temperatures are consistently warm before sowing directly outdoors. Plant seeds about one inch deep; they typically germinate within four to ten days under these ideal conditions.
Space plants 36 to 72 inches apart to accommodate their sprawling vines, which can reach 10 to 15 feet in length. Provide consistent moisture throughout the season, but reduce watering once fruits begin to ripen to prevent splitting. Apply mulch around the base to retain soil moisture and suppress weeds while feeding plants as needed for vigorous growth.
Watch for common issues like powdery mildew or cucumber beetles; practice crop rotation and remove infected leaves early to prevent spread. Harvest fruits when they reach full size, typically taking 70 to 100 days from sowing. Look for a dull sound when tapped against the vine and a creamy yellow spot on the underside to confirm ripeness before cutting.
When to Plant Watermelon
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | June | July – September | November – August |
| Zone 2 | May – June | July – August | November – September |
| Zone 3 | May | June – August | October |
| Zone 4 | April – May | June – July | October |
| Zone 5 | April | May – July | September – October |
| Zone 6 | April | May – July | September – November |
| Zone 7 | March – April | May – June | September – October |
| Zone 8 | March | April – June | August – October |
| Zone 9 | February | March – May | July – September |
| Zone 10 | January – February | March – April | July – August |
| Zone 11 | January | February – March | June – July |
| Zone 12 | January | February – March | June – July |
| Zone 13 | January | February – March | June – July |
