Watermelons need warmth, water, sun, and space. But if you are short on warmth–you live in a short-summer region–or space, not much yard, you can still grow delicious, sweet watermelons in a home garden.
Large watermelons require 4 months of frost-free, very warm weather to come to harvest and that they can gobble up as much as 144 square feet of space. But if you have less than 90 growing days, you can still harvest a watermelon. (See the short-season list below.) And if you have as little as 12 to 16 square feet–that's 4 feet by 4 feet, you still have enough space to grow watermelon. (See the short vine or bush variety list below.)
Planting Watermelon for Best Results. Plant watermelons in light loam to sandy-loam soil; avoid planting in heavy or clay soil. Plant when the soil temperature has warmed to at least 70°F. (You can get a head start in cool regions by sowing watermelons indoors 6 weeks before planting out.)
Center your vine in the space you have, and dig a hole 3 feet in diameter and 12 to 18 inches deep, a bit deeper in the center. Add rich compost or planting mix to the hole and tamp it down; watermelons require consistent even watering, this compost-rich planting bed will serve as a moisture reservoir. Mound the soil above the re-filled in bed to 6 inches tall. Plant 5 to 6 seeds or set two starts on this mound. Thin to the strongest plant. Space mounds 12 feet apart unless you are planting the short vine, bush varieties listed below–then you can plant a third to half that distance.
Watermelon Water Requirements. Your yield will be small if you don't keep watermelons irrigated. If you depend upon rain and rain is in short supply, get as early a start as possible. Watermelon roots will do their part to find moisture; they will grow to 6 feet deep. Irrigation will increase yields.
Watermelon Pollination. Watermelon plants have separate male and female flowers so bees are required for pollination. Thin each planting mound to no more than two melons for best results.
Mulch. Once fruits begin to develop, place a board or thick straw mulch under each fruit; contact with soil can result in insect damage or rotten spots on the bottom of the fruit.
12 top watermelon choices to grow in the home garden:
Bush or short vine watermelons for small spaces.
• Bush Charleston Gray. (F) 90 days. High sugar content. Small, oblong fruit similar to Charleston Gray except for the smaller size of fruit and vine; weighs10 to 13 pounds. Gray-green rind; flesh deep red, fine-textured. Needs just 3 to 5 feet across. Ideal for small gardens. Open-pollinated.
• Bush Jubilee. (AN, F) 90-100 days. Sweet, high sugar content. Small, oblong fruit to 24 inches long; weighs 25 to 35 pounds. Light green rind with dark green stripes; bright red flesh, firm texture. Spreads just 3 to 5 feet. Open-pollinated.
• Bush Sugar Baby. 75-80 days. Juicy, sweet flesh. Small, round fruit; weighs 12 pounds; dark green rind with no stripes; red flesh. Vine spreads just 3 to 3½ feet. Open-pollinated.
Long vine watermelons–for larger spaces:
• Calsweet. (F). 90-92 days. Sweet. Large, oblong fruit to about 17 inches; weighs 25 to 30 pounds. Rind light green with dark green stripes; bright red flesh. Open-pollinated.
• Charleston Gray. (AN, F). 85-100 days. Excellent, crisp flavor. Large, cylindrical fruit to 24 inches long; weighs 30 to 35 pounds. The thin but tough rind is light greenish-gray; red flesh. Vigorous vine. Sunburn and heat resistant. Open-pollinated.
• Crimson Sweet. (AAS, AN, F). 80-97 days. Very sweet, high sugar content. Large, slightly elongated fruit to12 inches long; weighs 35 to 30 pounds. Thick, hard rind; light green darker green stripes; bright red flesh, fine texture. Open-pollinated.
• King of Hearts. 80-85 days. Sweet, delicious, crisp. Oval-shaped; thick green rind with medium green stripes. Bright red flesh, medium texture. Hybrid.
• Sugar Baby. 68-86 days. Big melon sweetness. Small, round fruit fits in the icebox, 6 to 8 inches long; weighs 8 to 10 pounds. Thick, dark green rind turns almost black; bright red-orange flesh, fine texture. Excellent for a home garden. Open-pollinated.
Short-season watermelon–less than 90 days:
• Cole's Early. 80 days. Sweet, good quality. Broad, oval fruit; weights15-20 pounds. Thin rind; dark green with light green stripes; light red flesh. Popular in northern states. Open-pollinated.
• Sugar Baby. See above.
• Fordhook Hybrid. 75 days. Juicy, delicious. Weighs 14 pounds. Red flesh. Vigorous grower.
• Yellow Baby. (AAS). 75 days. Sweet, excellent flavor. Small, round to oval fruit to 7 inches in diameter; weighs 8 to 10 pounds. Thin rind; light green with darker green stripes; bright yellow flesh. Good storage. Hybrid.
• Yellow Doll. 65-70 days. Extra sweet, crisp. Small, round to oval fruit; weighs 4 to 8 pounds. Thin rind; green with dark green stripes; yellow flesh. Semi-compact vine. Open-pollinated.
AAS: All-America Selection (resists most diseases)
AN: Anthracnose resistant
F: Fusarium diseases resistant
More tips at How to Grow Watermelon.