How Much Water Does a Watermelon Plant Need?

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The fruit of the watermelon plant

The watermelon requires growing conditions that mimic its native habitat in Africa, including ample water. Long growing seasons of warm weather and moist soil contribute to the growth of a juicy, rosy-fleshed fruit.


Watermelon seeds require water to start its metabolic process and begin growth. Sow seeds by using only enough water to dampen the soil. Allow the soil to dry between waterings during the germination process. Do not water the seeding the day before transplanting it.

Mature Plants

Watermelons thrive in moist soil and require 1 to 2 inches of water per week. Watering slowly allows the water to penetrate deeply into the soil, encouraging the development of a deep root system. Watering too much or too little causes the formation of a few dozen seeds in seedless watermelons.


University of Kentucky Horticulturist Rick Durham advises gardeners to reduce the amount of water given to watermelon plants when the fruit reaches approximately half its full-grown size. Restricting watermelons to less than an inch of water per week increases the sugar content of the mature fruit. Gardeners help the soil retain moisture during this period by covering the soil with a black plastic sheet or using organic mulch.