Growing Watermelon:
How to Grow Watermelon Organically

Growing watermelon is much easier than people tend to think. As long as you have healthy soil, plenty of garden space, access to good compost and organic fertilizer and at least some warmth and sunshine, then you will enjoy plump, juicy and seed-spittingly delicious watermelons straight from your garden.

Growing Watermelon: Plant Snapshot (Citrullus lanatus)

Growing Watermelon
  • Family: Cucurbitaceae (Gourd family)
  • Annual or perennial? Annual 100-130 days to maturity
  • Recommended varieties: AU Sweet Scarlet, Rainbow Sherbet, Raspa, Desert King
  • Cold tolerance: Warm Season – Will not survive frost and their seeds will not germinate in cold soil. Plant them at about a week after the last 32 degree F (0 degree C) temperature in spring
  • Required Sun: Full sun (at least 6 hours each day)
  • When planning vegetable crop rotation, group with crops from this family: Cucumber and Pumpkins
  • Companion plants:
    • Companions: Corn, Nasturtium, Radish
    • Avoid: Potatoes
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How to Plant Watermelon Plants

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Before planting watermelon seeds, be sure that the soil has reached at least 60 degrees F (15.5 C) and that all danger of frost has passed. To be sure the soil is ready when you plant, cover soil with black plastic or landscape fabric a few weeks before planting.

The seeds will need plenty of water, but be sure that their soil remains well-drained. Plant them in well-composted soil, and mix a good organic garden fertilizer into the surrounding soil.

You can also start your seeds off in a cold box or indoors. If you go this route, time your sowing so that you’re transplanting about three weeks later. Keep the temperature warm at first (about 85 degrees F/29 C), then turn it down to between 70 and 75 F (24 C) after germination.

There are two methods for growing watermelons in the garden: hills or rows. If you are a beginner, then traditional rows will make it easier to water, of which watermelons need plenty! Regardless, be sure that your watermelon plants will get full sunshine.

Watermelons’ sprawling vines and large fruits require plenty of space, so leave at least 5 or 6 feet (1.5 to 1.8 m) between plants.

Snapshot: Planting Watermelon Plants

  • Snapshot: Planting Watermelon:
  • Planting depth: about 1-2 inches (2.5-5 cm)
  • Spacing in rows: about 72-96 inches (182-243 cm)
  • Germination soil temperature: 60 degrees F minimum (15.5 degrees C)
  • Days to germination: 5 to 8 days
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Growing Watermelon: From Germination to Pre-Harvest

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Watermelons are hungry plants, so their soil should be kept well-weeded with a healthy layer of compost. Ongoing applications of liquid organic fertilizer may also be appropriate, especially if some of the new leaves emerge with a lighter-green color.

Keep the plants well-watered until the melons begin to grow, after which you can ease up a bit. Just make sure that the soil doesn’t dry out.
Always make sure they are well watered and because they can be attacked by a number of bugs, keep an eye on how they are progressing.

Snapshot: Growing Watermelon Plants

  • Preferred soil pH (see soil pH tester for more information): 5.5 to 7.0
  • Growing soil temperature: 60 to 95 degrees F (15.5 to 35 degrees C)
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Growing Watermelon: Harvesting Time

Usually the seed packet will give an estimation of when your chosen variety of watermelons will be ready, but expect about 3 months after sowing. A watermelon can be assessed as being ripe by looking at its belly. If the belly is a really nice buttery yellow or creamy color (not white), then the watermelon is ripe for picking and should simply be cut off and enjoyed fresh!

A ripe watermelon will also sound very flat when it is tapped… the noise is like a dull thud rather than the “ringing” sound heard when tapping a not-ready melon.

Snapshot: Harvesting Watermelon Plants

  • Time to harvest: Within about 3 months of sowing seed.
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Storing Watermelon Plants and Freezing Watermelon Plants

Watermelons are best eaten fresh, but they can keep for over a week if refrigerated. For up to 6 months storage, chopped watermelon pieces can also be frozen after the seeds have been removed.

Watermelon seeds will last for up to 4 years.

Storing Watermelon Plants & Freezing Watermelon Plants

  • Storage temperature: 45-50 degrees F (7.2-10 degrees C)
  • Humidity: 80 to 90% relative humidity
  • Storage life (unfrozen in above conditions): 7-10 days
  • Storage (frozen): 6 months
  • Seed Longevity: About 4 years
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Growing Watermelon: Pests & Diseases

The following pests and diseases have been known to affect the success of growing Watermelon Plants. For more information about preventing and controlling them, see Organic Garden Pest Control.


  • Aphids
  • Cucumber beetles
  • Cutworms
  • Grasshoppers
  • Squash bugs
  • Squash vine borers

Common Diseases

  • Angular leaf spot
  • Curly top
  • Fungus
  • Mosaic viruses
  • Powdery mildew
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YOUR Experience & Advice About Growing Watermelon

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