How To Grow Watermelons

Plant Type: Annual
Scientific Name: Citrallus lanatus
Light: Full sun
Soil Type: Light, fertile, deep and well drained
Soil Temperature: 70° – 75°
ph Range: 6.0 – 7.5
Watering: Average
Plant (Payson): May 25 – June 15
Planting Method: Seed or transplant
Germination (days): 4 – 10
Transplant: Recommended
Plant Characteristics:Vining – trellis or fence (smaller watermelons)
Maturity (days): 80 – 100
Common Pests: Aphids, cucumber beetle, flea beetle, squash bug
Common Diseases: Bacterial & fusarium wilt, mosaic,
powdery mildew


Watermelons grow prolifically if given ideal conditions. As with other melons, watermelons can be allowed to grow horizontally or vertically. If you decide to grow them vertically, they need a fence or other structure to support them. The fruit will become quite heavy, so it’s necessary to support the fruit with mesh bags, nylon stockings or similar devises. However you choose to grow them, be careful to keep the fruit from sitting on wet soil. Pieces of wood under the fruit can be effective. Another trick is to use the vine itself. Melons produce a lot more vine than they use, so the vine can be folded back to support the developing fruit.


Melons prefer a loose, well-drained soil rich in organic matter. Prepare the bed with compost and rotted manure as early as the soil can be worked in the spring.


Watermelons will cover a large amount of space in your garden and, although fun to grow, are not very practical for our gardens. If you wish to grow watermelon, consider the small watermelons now available on the market. Smaller varieties take a shorter time to grow and can easily be trained to a fence or trellis. Trellising aids in prevention of disease and rot that occurs when fruit is in contact with the ground.


Transplant seedlings after all danger of frost is past. Melons need warm weather to grow and set fruit. Place a small amount of all-purpose organic fertilizer in the planting hole and work it into the soil at the bottom. Place seedlings close to the lowest leaves and firm soil around them to keep plants upright.

planting watermelon seeds

Plant seeds 1 inch deep in loose, organic rich soil. Cover and firm soil over seed. Water seed bed and keep moist until seedlings emerge.


Begin mulching as soon as seedlings emerge. Continue adding mulch as plants grow. The goal is to have 2-4 inches of mulch during the heavy growing and producing season. This reduces weed growth and helps retain moisture.

Consistent watering is best, but don’t let the soil become soggy.

All melons are heavy feeders. Add a balanced organic fertilizer when planting and add side dressings every two weeks during the growing season. Critical times for both feeding and water are when the plants begin flowering and during fruit growth.

Use of a mulch should reduce weed growth, but if weeds do invade your garden, remove them by hand as soon as you see them. Be sure you remove the root as well or it might grow back. Weeds spread easily by seed and can migrate to neighboring plots, and some weeds harbor “bad” bugs, so weed control is very important.

Bacterial wilt, mosaic, powdery mildew, scab, and fusarium wilt. If your vines do not appear healthy check for bugs first and then go to the website for information about diseases and their control.

Striped and spotted cucumber beetles, aphid, flea beetle, and squash bugs are the most common critters that may feed on your melon vines and sometimes the fruit as well. Even sow bugs can be a problem if the fruit is sitting on wet ground. Squash vine borers can also attack melons. Check regularly for aphids, especially on the undersides of leaves, as they can cause bacterial wilt.


Harvest the fruit when small cracks appear and begin to circle the stem, leaving the stem to look shriveled. Fruit should break away easily. If you have to cut the stem, the watermelon probably isn’t ripe. Other signs of ripening fruit: When the “curlycue” near the stem of the watermelon dries up and turns brown and the “belly button” where the flower originally was becomes flattened instead of indented. And if all else fails consult your favorite “ripe watermelon” expert!



Watermelon is best when eaten fresh and it’s great in salads. Rinds can be pickled, or fruit can be frozen. Watermelon is an excellent source of vitamins A, B, and C.


 Helpful Links

To aid in your gardening success, here are some useful, trusted links for more information on watermelon.

How To Mulch Your Garden | Types of Mulch – The Almanac

What Is Mulch | How To Use 8 Types in Your Garden – The Spruce

How To Mulch Your Garden In The Fall – The Spruce

Please remember Payson Community Garden is an organic garden. Some of these sites may contain recommendations for non-organic products. Please see this website or Plant Fair Nursery website for a list of recommended products
that meet the organic standards of Payson Community Garden.

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