Horticultural Planning Records Est. data · NOAA 1991–2020 · USDA 2023

Vegetable · Brassicaceae

How to Grow Watermelon Radish

Cool season Frost hardy Full sun
Days to maturity 50–65
Spacing 4"
Plants / sq ft 3
Season Cool

Planting Watermelon Radish

Watermelon Radish is a cool season vegetable in the Brassicaceae family. Getting the timing right is the difference between a strong stand and a disappointing one, so the windows below are given relative to your own last spring frost and first fall frost rather than a generic calendar date. Look up your local frost dates and count back or forward from there.

You can sow Watermelon Radish directly into the garden 0–2 weeks before your last frost.

For a fall crop, sow 8–10 weeks before your first fall frost so plants mature as the weather cools.

Spacing and Planting Depth

Give Watermelon Radish room to mature. The figures below come from verified extension and seed-supplier data for typical varieties.

Spacing in row4 inches
Row spacing12 inches
Plants per sq ft3
Planting depth0.5 inches
Sun requirementFull sun

Days to Maturity

Watermelon Radish reaches maturity in 50–65 days from sowing.

Watermelon Radish is ready to harvest after about 58 days. Harvest before summer heat or, for fall crops, before a hard freeze, to keep quality high.

Conditions and Care

As a cool-season vegetable, Watermelon Radish does its best growing in the cooler weather of spring and fall and tends to bolt or turn bitter in summer heat. It is frost hardy and can shrug off light freezes, so it can stay in the ground later into the season than tender crops.

Watermelon Radish needs full sun — give it at least six hours of direct light a day for the best growth and flavor. Sow seed about 0.5 inches deep, then keep the soil evenly moist until seedlings establish.

Watermelon Radish belongs to the Brassicaceae family; rotating where you grow members of this family each year helps limit the build-up of soil-borne pests and disease. Watermelon Radish is generally grown as a single planting each season rather than succession sown.

Companion Plants

Pairing Watermelon Radish with the right neighbors can improve growth and deter pests; a few combinations are best avoided.

Grows well with: Lettuce (Loose-leaf), Cucumber

Plan your Watermelon Radish schedule

Watermelon Radish is typically grown as a single planting per season rather than succession sown. Plan your full garden →

Data sources
  • Johnny's Selected Seeds