How to Use Black Plastic Mulch for Watermelons


Watermelon requires a long, warm growing season and plenty of water to reach peak flavor at harvest time. In areas with short summers starting the watermelon seeds indoors helps extend the growing season, but using black plastic mulch ensures you get the most out of the summer heat for your plants. Black plastic helps warm the soil while preventing weeds and conserving soil moisture. Black plastic mulch also keeps the melons from setting directly on the soil, which prevents some pest and disease issues in the fruit.

Step 1

Prepare the garden bed once all danger of frost is past in spring and the soil temperature is above 65 F. Lay a 2-inch layer of compost over the bed and apply a starter fertilizer following label application recommendations. Till it into the soil to a 10-inch depth using a hoe or power tiller.

Step 2

Lay a drip irrigation hose along each planting row. Space rows 7 feet apart so the watermelon vines have room to sprawl.

Step 3

Dig a 2-inch trench around the perimeter of the planting bed. Set the soil removed from the trench outside the bed.

Step 4

Lay the black plastic mulch over the entire bed, pushing the edges into the trench. Refill the trench with the removed soil and tamp it into place. This holds the mulch down so wind doesn't pull it up.

Step 5

Cut a 3-inch diameter hole in the plastic mulch for each watermelon seedling, spacing the holes 3 feet apart. Plant the seedlings to the same depth they are at in their nursery pots and firm the soil lightly around them.

Step 6

Water the watermelon seedlings immediately after planting so any air bubbles in the soil around the roots collapses. Continue to water them via the drip irrigation hoses, providing approximately 1 inch of water per plant each week.

Step 7

Harvest watermelons when the small tendril-like vines near the stem turn brown and dry and the skin of the melon becomes dull. Cut the melon vine off 3 inches from where it joins to the melon to harvest.

Tips and Warnings

  • Black plastic mulch should be removed each fall and replaced in spring, otherwise it will shred and removal becomes difficult.

Things You'll Need

  • Compost
  • Starter fertilizer
  • Power tiller
  • Drip irrigation hose
  • Shovel
  • Plastic mulch
  • Knife


  • Fort Valley State University Extension: Black Plastic Mulch
  • University of Illinois Extension: Watermelons
Keywords: mulching watermelon plants, using black plastic mulch, plastic mulch and melons

About this Author

Jenny Harrington is a freelance writer of more than five years' experience. Her work has appeared in "Dollar Stretcher" and various blogs. Previously, she owned her own business for four years, selling handmade items online, wholesale and via the crafts fair circuit. Her specialties are small business, crafting, decorating and gardening.