Introductory Guide To Growing Watermelons

Growing watermelons in your own garden is a sweet and rewarding hobby. While you could buy watermelons from the store, growing your own gives you the ability to plant any cultivar you like, such as extra sweet heirloom varieties, high yielding hybrid types or even giant varieties. Tending your own watermelon plants also allows you to choose to use more natural methods of insect pest and disease control more so than what is commonly available for commercially grown crop. Furthermore, growing your own watermelons allows you to plant and harvest when you would like, granted of course that this is during the growing season in your region.

This article will give you a basic introduction of how to grow watermelons.

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When you think about which varieties to grow, consider the qualities you want in your watermelons. You want to select your cultivars based on what you want such as, size, sweetness in flavor, insect and disease resistance, and when to harvest. You may select giant producing varieties like the Carolina Cross which may take up to 4 months to harvest from seed or smaller fruited varieties like the Sugar Baby which is very sweet and can harvest in as little as 75 days. In general, you can expect larger fruited varieties and heirlooms to take over 110 days to harvest whereas mid size varieties like the Crimson Sweet and smaller will take 90 days or less to harvest. When searching for seeds, look for reputable seed companies with good seed selections. You usually find these in local garden centers and through online catalogs. Consider seed saver exchanges and friends and family members that maybe gardeners and amateur seed savers to locate heirloom varieties.


Try to have a soil test performed to give you a good idea about the nutrients your soil needs. In general you want your soil to have a neutral pH, be well draining and contain plenty of rich organic matter. Planting a cover crop of wheat or winter rye in late fall that is tilled up in the spring is a good way to add organic matter to the soil.


Watermelons should be planted after the last frost of the season in your region. To get seeds started you can directly sow seeds into the ground or start seeds in pots for later transplanting. If directly sowing seeds, be sure to put at least 3 – 4 seeds per hill (reduce to the strongest 2 plants after about 3 weeks) and make sure the soil stays warm (perhaps through a greenhouse) but not above 90° Fahrenheit and remains slightly moist. If you are transplanting seedlings, keep the seeds while in the pots, slightly moist but not soaking and use care not to injure roots when planting. A temperature of 75° to 80° Fahrenheit is necessary to start the germination process.


Watermelon plants grow very large running vines and need lots of space to grow in. Larger size fruited plants (fruit sizes of 60 lbs or more) typically need 120 square feet or more per hill (2 plants) to grow in whereas midsize fruited plants (up to 30 lbs) need approximately 80 square feet per hill (2 plants). Smaller fruited plants (fruit size up to 10 lbs) can get by with 60 square foot per hill (2 plants). These spacing requirements should be adjusted accordingly to seed packet information guidelines for specific cultivars and for hills with more than 2 plants.


Watermelons need a lot of sun and heat to grow well. Find the sunniest place in your garden to plant in, this will help to ensure you to get as abundant a crop as possible. Warmer region climates are ideal for growing watermelons, because for watermelons unlike many other warm season crops, the more sun and heat the better. Some giant watermelons growers even place plastic sheets over the soil at the base of their plants to heat up the roots and do so with great success.


Feed watermelon plants with soil amendments and fertilizer applications according to your soil test report, if available or with fertilizer applications with a balanced amount of Nitrogen, Phosphate, and Potash. As male and female flowers begin to form, stop fertilizer applications until after fruit has begun to set. Follow all fertilizer recommendations to avoid harming the plants.

Watermelon plants should receive water or rainfall often. Applying the equivalent of 1 to 2 inches of rainfall in water over the entire plant is ideal. Avoid getting plant leaves wet as this moisture can provide a host for bacteria and disease pathogens to attack the plant.


To control insects, use multiple methods of defense. Squash bugs and Cucumber beetles are two very harmful insects to watermelon plants as they consume nutrients from the plants, eat plant foliage and fruit, as well as infect plants with various harmful diseases. Applying Neem oil and Garlic Barrier are a couple of natural pesticides effective at controlling these pests. Using insect barrier floating row covers over plants and direct handpicking and disposing of insects are two very effective methods to combat these pests. Be sure to always use care and caution when handling or applying any type of pesticide, whether conventional or organic.

Using regular applications of sulfur or copper ingredient based fungicides are helpful to maintaining plant health. Using good crop sanitation techniques such as removing crop debris at the end of each season, immediately removing identifiably diseased plants from the garden, leaving space between plants to allow good air flow, etc. are good ways to minimize disease presence in your garden. Wearing gloves between working with different types of plants is also helpful to preventing disease from spreading. A major component to controlling disease in your garden is controlling insect pests.


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Once your watermelons have set fruit that has been growing for 4 weeks or more (give or take a week depending on cultivar size) you want to watch them closely so you will be ready when it comes time for harvest. The window for harvesting is small so here are a few techniques you can use to determine the ripeness of your watermelons. Just before picking, the skin of the watermelon should be hard and not flexible or soft. The underside of the melon should have a light yellow (bright yellow is past optimum ripeness), almost white color. At harvest time, the watermelon stem and tendrils (little vine like attachments that secure the plant to the ground by grabbing and wrapping around weeds, rocks, etc.) will have began to dry up and turn brown.

Have fun growing, harvesting and eating your watermelons.


Growing Watermelon in the Home Garden, Ted W. Gastier,

Ohio State University Fact Sheet, HYG-1626-95

Melons: A Growing Guide, Organic Gardening