Watermelon

Watermelon, Citrullus lanatis, originated in South and East Africa. Large (20-to-40-pound), red-fleshed, seeded watermelons make up the bulk of those sold commercially, but smaller (10 pound) icebox types are also grown on significant acreages. Yellow-fleshed and seedless types are also grown, but for the cultivars available now, seed is much more expensive. Production may be more difficult and yield lower than for the standard cultivars.

Climatic Requirements

Watermelons are also warm-season crops, requiring a 4-month frost-free period, minimal soil temperatures of 70 degrees F for germination and soil temperatures of 75 to 85 degrees F for optimal germination.

Watermelons are not as likely as muskmelons to produce bland-tasting (low sugar) fruit when over-irrigated. They can tolerate higher water levels and will, in fact, develop blossom end rot, a calcium deficiency if either moisture or Ca is lacking. There are reports, however, that excess nitrogen can reduce sugar content.

Watermelon nutrient recommendations based on soil tests.

Fertilizer timing			Nitrogen lbs/acre	Soil phosphorus level-lbs/acre P2O5				..	..	Soil potassium level-lbs/acre K2O
				Low	Med	High	V. high			Low	Med	High	V. high
Total recommended			85-100	150	100	50	25	..	..	200	150	100	50
Broadcast and disk in or drill deep			25-50	100	50	0	0	..	..	150	100	50	0
Band-place with planter*			25	25	25	25	0	..	..	25	25	25	25
Sidedress when vines begin to run			25-50	25	25	25	25	..	..	25	25	25	25

Apply 1 to 2 pounds of boron per acre with broadcast fertilizer.