How Long Does Watermelon Take to Grow & What Month Do You Plant?
Written by Mary Simpson; Updated December 15, 2018
1 How Much Cold Can Watermelon Plants Take?
2 Watermelon: The Varieties & When to Pick Them
3 The Best & Biggest Non-Hybrid Watermelons
4 Watermelons Produced Per Vine
Producing the biggest fruit on the longest vines, the watermelon (Citrullus lanatus) also has the longest history of any of the melons. And most eaters agree: it is the sweetest of the bunch. The first recorded evidence of a watermelon crop occurred more than 5,000 years ago in Egypt. Depicted in hieroglyphics, watermelons were placed in the tombs of the pharaohs. Today, varieties of the warm-season annual range from 1-pound personal melons to 100-pound contest entries.
Planting Watermelons
The ideal 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 should not be transplanted until after the last average frost date in the spring, when the soil temperature at a depth of four inches is at least 60 degrees F. Starting seed indoors about six weeks before planting gives you a head start when the soil is warm enough. If you use 4-inch or larger biodegradable paper or peat pots, the plants can be set out, pot and all, without disturbing the roots. Watermelons cannot tolerate frost and should not 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 above, cover the ground with clear plastic film to warm it before setting out the plants.
Care of Melons
To develop the sweetest, most succulent flesh, watermelons require eight to 10 hours of direct sunlight daily. They prefer a soil rich in organic matter, such as compost or rotted manure. Dig a trench two inches from the side of the row and four to six inches deep, and add about four pounds of 10-10-10 fertilizer per 60 to 90 feet in a row before planting. Don't allow the seed to come in contact with the fertilizer. When the vine runners are nearly six inches long, sprinkle 10-10-10 fertilizer two to three feet from the row at a rate of two to three pounds of fertilizer per 60 to 90 feet of row, and lightly mix the fertilizer into the soil surface. Because they have a relatively shallow root system, melons need constant water, especially as the fruits are growing. During periods of hot weather, it is normal for the melons' leaves to wilt by late in the day, but they should recover by the next morning. If a plant sets one fruit early, pinch it off to encourage multiple 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 work well if the vines are tied in place with cord or cloth.
Varieties' Days to Harvest
Generally, watermelons reach harvest 70 to 85 days after sowing. As might be expected, smaller varieties will usually be ready before larger ones, but not always. Some early watermelons, of six to 10 pounds, 'Golden Crown,' 'Sugar Baby,' 'Yellow Baby' and 'Yellow Baby,' mature in 70 to 75 days. Other watermelons, such as 'Charlestone Gray,' 'Sunny's Pride' and 'Sangria,' take 80 to 85 days. 'Crimson Trio,' 'Honey Heart,' 'Nova,' 'Tiffany' and 'Queen of Hearts' are seedless and also require 80 to 85 days or more to ripen.
Signs of Ripeness
As watermelons near maturity, the vine's tendrils begin to turn brown and die. Some varieties develop a circular crack around the stem. Others soften at the blossom end. If one side of the watermelon was resting on the ground, it will go from white to yellow. Thumping a ripe melon should produce a dull sound. As you see some of the signs emerging, limit water for the last week before harvesting, to concentrate sweetness. After picking, watermelons will keep in the refrigerator up to a week, but they will last two to three weeks before cutting, without refrigeration, if kept in a cool, slightly moist place.
Missouri Botanical Garden: Citrullus Lanatus
Clemson University Cooperative Extension: Watermelons
Texas A & M Agrilife Extension: Growing Melons
University of Illinois Extension: Watermelon
Mary Simpson began her writing career in 1968 on a Dallas oil magazine. Besides reporting and editing for several small Texas newspapers, Simpson has written for "Petroleum Engineer Magazine," "Denton Today Magazine" and put out an employee newsletter for a FEMA facility. She holds a B.A. in journalism and an M.A.in English, both from the University of North Texas.
Simpson, Mary. "How Long Does Watermelon Take to Grow & What Month Do You Plant?" Home Guides | SF Gate, http://homeguides.sfgate.com/long-watermelon-grow-month-plant-51141.html. 15 December 2018.
Simpson, Mary. (2018, December 15). How Long Does Watermelon Take to Grow & What Month Do You Plant? Home Guides | SF Gate. Retrieved from http://homeguides.sfgate.com/long-watermelon-grow-month-plant-51141.html
Simpson, Mary. "How Long Does Watermelon Take to Grow & What Month Do You Plant?" last modified December 15, 2018. http://homeguides.sfgate.com/long-watermelon-grow-month-plant-51141.html
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