What's sweet, delicious, easy to grow -- and one of the most healthful crops you can harvest from your garden? Why, watermelon, of course! Just one serving of watermelon gives you about a third of your daily requirement of Vitamins A and C, an ample amount of potassium and the healthful antioxidant lycopene, all for only about 80 calories. And the taste of its crisp, juicy flesh is the essence of summer.
Watermelons have made a long journey to get to our fields and gardens. They are thought to have originated in central and southern Africa almost 5000 years ago. From there they made their way along trade routes to Egypt and on to India, China, and Europe, where they became a popular crop in the warm Mediterranean countries. Watermelons were brought to the New World with colonists and African slaves by the 1500s and were eagerly taken up and cultivated by native American tribes. Now, centuries later, we have a mind-boggling array of watermelon varieties to choose from -- ones with red, yellow and orange flesh; ones with seeds or without; large oblongs weighing as much as 130 pounds and little round icebox melons that tip the scales at a mere 6-10 pounds. So choose from the many watermelons we offer for a harvest next summer of health and good taste.
Watermelons are our specialty! Here is just a sampling of the many varieties we carry -- open-pollinated and hybrid, seeded and seedless.
'Big Stripe' (Large Seed) (85 days) - The large oblong fruits of this seeded hybrid average as much as 30 pounds and have sweet red flesh.
'Desert Storm' (80-85 days) - An early, very uniform, high-yielding hybrid variety with sweet, crisp red flesh and small, mottled brown seeds.
'Mid-Night' (80-85 days) - Round fruits average 15-18 pounds and have a beautiful, velvety dark rind and sweet red flesh.
'Cobb Gem' (100 days) - One of the largest melons around, this open-pollinated variety produces fruits weighing as much as 130 pounds!
'Dixielee' (90 days) - Round melons with smooth, striped rinds, attractive red flesh and black seeds average 20-30 pounds and ship well.
'Orange Crisp' (92 days) - This seedless variety produces round-oval, 14-18 pound fruits with vibrant orange flesh that is very crisp and sweet.
While traditionalists may think that spitting out the seeds is an essential part of the true watermelon experience, lots of folks appreciate the ease of eating that seedless watermelons provide. And research has shown that seedless watermelons have the highest levels of healthful lycopene and a longer shelf life than seeded fruits, as the watermelon flesh begins to break down first in the vicinity of the seeds as the fruits age.
Where do the seeds come from to grow a melon with no seeds? Seedless watermelons are hybrids that are the result of a cross between diploid plants, with 22 chromosomes per cell, and tetraploid plants, with 44 chromosomes per cell. The incompatibility of the chromosomes produces triploid plants that don't set viable seeds, although you may find a few small, white, undeveloped seeds that can be eaten along with the flesh.
Start the seeds of hybrid seedless varieties indoors in peat pots, ideally on a heat mat. They need very warm soil temperatures to germinate and rarely make a good stand if direct seeded.
The seedcoat of hybrid triploids is more likely to adhere to the developing seed leaves, injuring them. Sowing the seeds with the pointed end up at a 45 to 90 degree angle usually prevents this problem.
Seedless hybrid triploid varieties don't produce sufficient amounts of viable pollen, so a seeded watermelon pollinator variety should be interplanted with the seedless ones to ensure adequate pollination and good fruit set. In a home garden, plant one seeded vine for every two seedless ones.
Watermelons will do best in full sun and rich, loose soil that is high in organic matter. Wait until the soil is warm and all danger of frost is past before sowing seeds or setting out transplants. In warm season areas of the Deep South and Southwest, you may be able to sow multiple crops; just make sure you plant about 110 days before the first expected fall frost.
Sow seeds 1/2 inch deep. You can plant seeds in hills spaced 6-12 feet apart, sowing 4-6 seeds in a circle about a foot across and thinning to the two strongest vines. Or plant in rows, spacing plants 5-7 feet apart in the row and allowing at 4-6 feet between rows.
Row covers placed over newly seeded or transplanted melons are a great way to keep out pests such as cucumber beetles, but they need to be removed when the plants begin to flower so bees can get in to pollinate.
Keep your vines vigorous by giving them a dose of soluble fertilizer such as fish emulsion as the fruits begin to form. And make sure your vines get consistent water throughout the season. An organic mulch such as straw will keep weeds down and help conserve soil moisture. About two weeks before you you expect to harvest, cut back on watering; this boosts the melons' sugar content and makes them sweeter.
Pinching off the growing tips of the vines in midsummer helps the plant to concentrate its energy on ripening fruits. In short-season areas, pinch off the tips of all the shoots. In hot, long-season areas, pinch only the main growing tip. Allow the side shoots to grow to encourage dense foliage that will shield the developing melons from sunscald.
To pick your watermelon at its peak of ripeness, check the curly tendrils on the stem near where it attaches to the fruit. The melon is ready when the tendrils have changed from light green to dry and brown. The spot on the bottom of the melon where it rested on the ground should be yellow, not light green or white. And the skin should be dull and tough enough that it's hard to dent with a thumbnail.
Q: The growing season where I live is fairly short. How can I raise watermelons successfully?
A: Start by choosing early varieties such as hybrid 'Yellow Doll' that ripens in just 68 days or open-pollinated 'Mickylee' that matures in 72-78 days. Then get a head start by sowing seeds early indoors in peat pots 3 to 4 weeks before your last spring frost date. Preheat the soil in the garden by spreading black or red plastic or infra-red transmitting (IRT) mulch a week or two before planting time. Keep the mulch in place as vines grow, laying soaker hoses or drip irrigation beneath the mulch to provide water to the roots. Cover transplants with row covers when you set them out to moderate temperatures around plants, but remove the covers when plants begin to flower.
Article published on December 4, 2012.