Producing the largest fruit about the longest vines, the watermelon (Citrullus vulgaris) also has the longest history of any of the melons. And most dieters concur; it is the sweetest of the bunch. The first recorded evidence of a watermelon crop occurred over 5,000 years ago in Egypt. Depicted at hieroglyphics, watermelons were put at the tombs of the pharaohs. Now, varieties of this warm-season yearly range from 1-pound private melons to 100-pound competition entries.
The perfect date to plant watermelons varies according to the climate of the region. To produce the sugar necessary for sweet fruit, the melons need hot weather. Seedlings shouldn’t be transplanted until three to four weeks after the last average frost date in the spring. Starting seed indoors about six weeks before planting gives you a head start when the soil is warm enough. Should you use 4-inch or bigger biodegradable paper or peat pots, the plants can be set out, pot and all, without disturbing the roots. Watermelons cannot tolerate frost and shouldn’t be planted where night temperatures dip below 50 degrees F. Lower temperatures cause the fruit to lose flavor. Because melons grow best when the soil temperature is 75 degrees or over, cover the ground with clear plastic film to warm it before putting out the plants.
Care of Melons
To develop the sweetest, most succulent flesh, watermelons need eight to 10 hours of direct sunlight each day. They favor a soil full of organic matter, like compost or rotted manure. Insert about 1/2 cup bonemeal each foot to aid early root development. Because they have a relatively shallow root system, melons need continuous water, especially as the fruits are growing. During periods of hot weather, it is normal for your melons’ leaves to wilt by late in the day, but they must recover by the next morning. If a plant puts one fruit ancient, pinch it off to encourage numerous fruits to develop, or it will suppress fruiting until the one matures. Watermelon vines are weaker than those producing other trailing fruit, so even the smaller types need support. Fences or A-frames function well if the vines are tied in place of cord or fabric.
Varieties’ Days to Harvest
Normally, watermelons reach crop 65 to 90 days after sowing. As may be expected, smaller types will ordinarily be prepared before bigger ones, but not consistently. Some ancient icebox-size watermelons, of 2 to 4 pounds, “Early Midget,” “Garden Baby,” Golden Midget” and “Little Baby Flower,” adult in 65 to 70 days. Other petite melons, like “New Hampshire Midget,” “Sugar Baby” and “Petite Sweet,” take 75 to 80 days, in addition to the oblong “Desert Storm” and “Royal Majesty.” “Charleston Gray,” “Black Diamond,” “King and Queen,” “Navajo Sweet” and “Moon and Stars” are notable bigger melons that need 90 days or longer to ripen.
Signals of Ripeness
Because watermelons near maturity, the vine’s tendrils start to turn brown and die. Some varieties develop a circular crack around the stem. Other people soften at the blossom end. If one side of the watermelon was resting on the ground, then it will go from white to yellowish. Thumping a ripe melon must produce a dull sound. As you find some of the signs emerging, limit water for the last week before selecting to concentrate sweetness. After picking, watermelons will remain in the fridge up to a week, but they will last two to three weeks before cutting, without refrigeration, if kept in a cool, somewhat moist place.