Watermelon Vine Care

Planting Considerations

• Watermelons produce long taproots that don't tolerate transplanting well. The young vines also can't tolerate cold weather, so you must plant them outdoors only after the risk of frost has passed. Start the seeds inside up to three weeks before you plan to transplant them to the garden bed. Use a biodegradable peat pot so you can plant the entire pot and avoid root disturbance. Sow seeds about 1 inch deep in the pots. Provide them with plenty of warmth and sunlight while keeping the soil moist.

Space and Weed Concerns

• Provide the watermelons with plenty of space in the garden so the vines can spread and sprawl as needed. Planting at least six feet apart gives the watermelons the required space within the row, and make the rows seven to 10 feet apart so you can move between the plants when working in the garden. Watermelons don't tolerate weed competition in the bed. It's necessary to pull the weeds between the plants until the vines begin to sprawl. Once the vines cover the bed they suppress most new weed growth. Black plastic mulch over the planting bed also prevents weeds while keeping the soil warm for the melons.

Water and Fertilizer Needs

• Though watermelon fruits consist primarily of water, the plants require minimal irrigation. The deep roots seek out water beneath the soil, so surface irrigation is only a rare necessity. Water the plants during extended dry periods when more than a week passes without natural precipitation. Provide enough water so the top 8 inches of soil feels moist. Watermelons also require only minimal fertilization if grown in rich garden soil. Provide a starter fertilizer at the time of transplanting to encourage early root and vine growth. Watermelons don't need fertilization throughout the growing season.

Fruiting and Harvest

• Ripe watermelons don't separate from the vine, so it's necessary to inspect the fruits regular to determine harvest time. Watermelon fruits develop a hard, dull-colored rind as they approach maturity. The spot on the bottom that rests on the soil, called the ground spot, changes to a cream color once the fruit is mature. Inspect the vine where it attaches to the melon. Once mature, the small curly tendrils at this connection spot turn brown and dry. Cut the watermelon from the vine with a sharp knife to prevent damage to the fruit or the vine.