Growing watermelon

Types

Clemson HGIC 1325 (South Carolina): watermelons (Citrullus lanatus) are warm-season crops. Average air temperatures between 70 and 85 °F. Melon seeds do not germinate well in cold soil. Type notes on their sheet — not a cultivar mill.

Timing

Clemson HGIC 1325 (South Carolina): Clemson lists soil temperature at the 4-inch depth of 60 to 65 °F before planting, and after-last-frost timing. Timing on their sheet — not a national plant date.

Spacing

Clemson HGIC 1325 (South Carolina): Clemson lists rows 6 to 8 feet apart. In-row 5 to 6 feet; or 4 feet on 6-foot rows and 3 feet on 8-foot rows. Rule of thumb 24 square feet per plant. Seed about 1 inch deep. Spacing on their sheet — not a BioArva average.

Limit

South Carolina HGIC 1325. Watermelon stays on this sheet. Muskmelon spacing is not on this hub.

Types

Maryland Extension (Maryland): watermelon (Citrullus lanatus) vines range in length from 6 ft (bush types) to 20 ft. Very tender warm-season annual. Frost will injure top growth. Type notes on their sheet — not a cultivar mill. Maryland’s attributed hardiness wording — not a planting-safety promise.

Timing

Maryland Extension (Maryland): direct sow when all danger of frost is past and the soil is warm. Start seeds indoors 3 weeks prior to transplanting. Maryland timing — not a national plant date.

Spacing

Maryland Extension (Maryland): watermelon 3 to 4 feet in-row by 6 to 7 feet between rows, depending on cultivar. Or plant 2 to 3 plants in hills spaced 6 to 8 feet apart. Spacing on their sheet — not a BioArva average.

Limit

Maryland melons garden page. Watermelon 3–4 ft spacing stays Maryland. Muskmelon spacing is not on this hub.

Types

UMN Extension (Minnesota): watermelon and honeydew are more cold-sensitive than cantaloupe. Type notes on their sheet — not a cultivar mill.

Timing

UMN Extension (Minnesota): you can direct seed or transplant between mid-May in southern Minnesota and late June in northern Minnesota. Plant only after the soil temperature has reached 65 °F. Minnesota timing — not a national plant date.

Spacing

UMN Extension (Minnesota): plant the seeds ½ to one inch deep. Sow 2 or 3 seeds in groups 18 to 24 inches apart. Space rows 5 to 6 feet apart. After the seedlings emerge, choose the strongest plant in each group and remove the others. Spacing on their sheet — not a BioArva average.

Limit

Minnesota melons sheet. Mid-May to late June and 18–24 in stay Minnesota. Not fertilizer.

Types

Illinois Extension (Illinois): watermelon vines require considerable space. Type notes on their sheet — not a cultivar mill. Illinois’s attributed warmth requirement — not a planting-safety promise.

Timing

Illinois Extension (Illinois): plant after the soil is warm and when all danger of frost is past. Illinois lists soil warmed above 65 °F. Illinois timing — not a national plant date.

Spacing

Illinois Extension (Illinois): plant 2 to 3 seeds one inch deep in hills spaced 6 feet apart. Allow 7 to 10 feet between rows. After the seedlings are established, thin to the strongest plant per hill. Single transplants 2 to 3 feet apart or double transplants 4 to 5 feet apart in the rows. Spacing on their sheet — not a BioArva average.

Limit

Illinois watermelon page. After-frost timing and 6-ft hills stay Illinois. Not fertilizer.