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UC Master Gardeners of Santa Clara County

Watermelon

Whole watermelon with dark green stripes beside two halves revealing deep red flesh with black seeds.

Garden Help > Fruits & Nuts

Watermelon are large vining plants that need lots of sun, water, and room to ramble in full sun. 

Cultural tips for growing watermelon, UC IPM

Pest management

Pests and disorders of watermelon, UC IPM

Planting

  • Transplant or direct seed in May to June.
  • For best results, wait until daytime temperatures are regularly over 75°F and soil temperature is over 70°F.
  • If growing your own seedlings, start the seeds 4 weeks before you want to plant.
  • Use floating row covers to protect seedlings and transplants from cool air temperatures and early insect pests. Remove the covers when plants start to blossom.

Harvesting

  • July to October, depending on variety.
  • Like all members of the cucurbit family, watermelon have male and female flowers. Encourage bees with companion flower planting or consider hand pollinating female flowers.

More links

 Recommended varieties for Santa Clara County*

Charleston Gray, Moon & Stars, Orangeglo, Osh Kirgizia, Sweet Siberian

* Many other varieties may also do well here in Santa Clara County. This list is based on UC Master Gardener trials, taste tests, and feedback from local growers.