How to Grow Radishes in a Pot

Select a 6- to 8-inch-tall container to use as a planting pot, preferably one with several drainage holes. If the container does not have any drainage holes, drill three or four 1/4-inch holes spaced evenly on the bottom. A window box, a gallon milk jug with the top cut off or a 6- to 8-inch-wide planting pot are examples of planting containers that work well for growing radishes.

Fill the pot with a 1/2-inch layer of gravel or small stones, such as pea stones. This improves drainage, but according to Iowa State University, these should not replace a drainage hole.

Fill the pot until the soil reaches about 1 inch from the rim with moist, high-quality and well-draining potting soil, available in nurseries and where garden supplies are sold. Preferably, use a soil mix with fertilizer mixed in; otherwise, mix in a water-soluble, all-purpose fertilizer using the rate recommended on the label.

Scatter the radish seeds on top of the soil and lightly cover them with 1/4 inch of moist soil. The Virginia Cooperative Extension recommends covering the pot with plastic wrap until the seeds germinate.

Place the pot in indirect light until germination. At that time, move it to an area that receives six or more hours of sunlight per day.

Thin seedlings to one plant every 2 inches when they reach approximately 4 inches tall. Choose the weakest plants to pull out.

Keep the soil moist and expect to harvest the radishes 25 to 35 days after planting, when the roots are about 1 inch in diameter.