Growing watermelon in your garden is similar to growing cantaloupe melons. This is one garden plant I am still learning to master. So if you’ve got tips to share, please do so.
Watermelon is a desert plant that comes from Africa. It does well in sandy soils (where taproots can grow deep to seek moisture) and dry climates. So, right off the bat, you know it is going to be a challenge to grow in gardens with our clay soils, shallow water table, and high humidity.
Two years ago, I selected an heirloom variety called Bush Sugar Baby. I wanted an “icebox” size melon and I wanted to be able to save the seeds from year to year rather than buy new seeds each year.
I planted one plant expecting it to fill one of my largest raised beds and I wasn’t sure how many fruits it would produce. Because its a “Bush” variety, the vine did not fill my garden bed; it grew to be about 42 inches in length is all. Without an abundance of bees working my garden, I only got one melon, but it was very tasty and the perfect size for my icebox and family of 2 (my husband and I are empty nesters now). Burpee sells this variety and claims each vine will produce two (12 pounds) melons.
Last year I planted four plants at staggered intervals and was thrilled to see bees from our beehives pollinating the blossoms.
[Photo at right taken as the first two vines started to set fruit and, true to Burpee’s description, each vine sported a couple of melons.]
Even though watermelon plants like it hot and dry, the drought of 2011 took its toll on my watermelon vines. My drip irrigation system, supplemented with hand watering, could not keep these vines alive.
Bob Randall (Year Round Vegetables, Fruits and Flowers for Metro Houston) suggests gardeners grow the icebox or mini watermelon varieties and let the farmers grow the monsters unless you have a great deal of room for the vines to sprawl. He recommends the Florida icebox varieties of Minilee and Mickylee as they have good resistance to the anthracnose fungus that wipes out watermelons in hot, humid June weather.
If you live in metro Houston, start seeds indoors on a heat mat (sprouting temperature range is 70° to 95° with 95° being ideal) early to mid-March and plant outside mid-April (be very careful not to disturb or damage roots when transplanting outside). Or, sew seed directly outdoors between March 15 and 31. If you live in Montgomery County, the AgriLife Extension planting calendar indicates you can sew seeds directly outdoors April 1 through July 31. Start early and stagger your plantings every 2 to 3 weeks to get a continuous harvest.
Like cantaloupe, watermelons will benefit from growing upright on trellises to increase air circulation around leaves and stems; tie up the melons with old pantyhose to provide support. Otherwise, give them plenty of room on the ground; the rule of thumb is 3 plants per 50 square feet of garden area. And they need full sun all day long with no other plants around them. [Pay attention to the spacing requirements on your seed packet and plant accordingly.]
Vines will grow best when daytime temperatures are between 70° and 85° but will tolerate higher temperatures. They send their roots down deep and supposedly do well with little water. My experience during the drought was just the opposite. Fluctuations in soil moisture will cause fruit to split and crack open.
Watermelon roots like loose soil high in nitrogen and phosphorus or compost. When you plant, add at least double the fertilizer you would use on other plants like squash. Once the plants begin to vine, lay down wet newspaper (3 to 4 sheets thick) and cover with 3 to 4 inches mulch to control weeds and keep fruit up off of moist soil.
The Big Question: How can you tell when a watermelon is ripe?
- Look at the skin. Unripe melons are shiny. As they ripen, their skin turns dull.
- Check the underside of the melon. The belly of the melon will turn a light cream or yellow color as it continues to mature. The best time to pick a ripe melon is just before the belly starts to lighten up.
- The tendril on the main stem nearest the attachment to the melon, as well as the next tendril out the stem, will die and turn brown. If it isn’t dead, the melon isn’t ripe yet. If it is dead, the melon MAY be ripe.
- Count the days from seed. As your melon plant nears its days to maturity, start thumping the melon. The sound may change when it is ripe.
- Your best bet is to look for the dead tendril, check the color of the belly, thump it and then wait a few days. When the melon is over mature, it will crack open.
Decide right now that the first time you plant a new variety, it is going to be a grand experiment. Watch and learn. Let your experience with the plant teach you how to take care of it and when to pick it.