Growing Guide: Radishes

Crop Stats

Radish Description:

The radish is a crisp, juicy, peppery root vegetable that makes a refreshing addition to salads when fresh or a tangy side dish when roasted. They’re the perfect spring and fall crop given their short growing time and the small amount of space they need to thrive. As a bonus, the radish greens are not only edible, but they’re also absolutely delicious!

Radishes are a biennial plant, meaning that their lifecycle is two years. In the first year, the bulbous roots develop and can be eaten. If you leave them in the ground over the winter, they’ll produce seeds in their second year.

What is the best container for growing radishes?

Since radishes are a root crop, they need plenty of room to grow downward. Plant them in a container that’s at least six inches deep. Be sure to use a container that’s wide enough to let your radish roots spread out as they grow.

How do you germinate radish seeds?

It’s preferable to direct-sow radish seeds where you’ll be growing them rather than germinating them indoors and transplanting them. Plant radish seeds about one-quarter-inch in the soil and one inch apart. 

When should you plant radish seeds?

Radishes are a cool-weather crop that doesn’t like air temperatures to exceed 75 degrees Fahrenheit. Sow the seeds when the average temperature is around 40 degrees F. Sow about four to six weeks before the last frost of the season. 

After the seeds sprout, make sure each seedling is at least one inch from its neighbors so they don’t crowd each other out. If it’s necessary to thin the plants, trim them at the base of the greens rather than pulling up the entire plant. Don’t throw away the baby greens that you snip – they’re delicious in a salad.

Sow the next round of seeds 10 days later and continue to do so for a continuous harvest through early summer. For a winter crop, sow seeds four to six weeks before the first frost of the season. 

Radish care guide:

Two things to pay special attention to when growing radishes are water and light. If radishes don’t get enough water while growing, the roots will be tough and woody. If they don’t get enough light, they’ll put all of their energy into growing larger leaves and the roots won’t have enough resources to develop. 

Water as soon as the top half-inch of soil is dry and make sure they enjoy six to eight hours of sunlight every day. Catch weeds as soon as you can because the little radishes can easily be choked out. While the seedlings are small, snip rather than pull weeds to avoid disturbing the radish roots.

A layer of mulch will help insulate the soil from high temperatures, keeping the cool-loving radishes happy and healthy. 

Harvesting and storing radishes:

Most radishes will be ready to harvest in 30-40 days. Keep an eye on them to avoid letting them get too large, as large radishes are woody and bitter. In general, they’re ready to pick when you can see their shoulders peeking up from the soil. If you’re not sure whether they’re large enough to harvest, poke a finger down into the soil to gauge their size. If they’re too small, leave them in the ground to mature a bit more.

Pull straight up from the base of the greens. If there’s a lot of resistance, use a fork or your fingers to loosen up the soil around the radish, then pull it up and out of the ground.

Cut the radish greens from the roots and wash and dry them well. Cut the long, thin “tail” from the end of the radish and wash well, then dry. Store the roots in a container in the produce drawer of your fridge. They should be good for one to two weeks. Store the greens in a separate container with a paper towel, where they’ll stay fresh for up to three days.

Harvesting radish seeds:

If you’re hoping to save some seeds from your radishes, don’t harvest all of them in their first season. Leave a few in the ground over the winter. The following summer, the leaves will grow back and eventually sprout flower stalks, which will develop small seed pods. Leave the pods on the stalks until they’re brown and dried out, then snip them off with scissors.

Squeeze the pods over an open container. Pick out the pods and other non-seed plant material. Spread the seeds out on a flat surface and allow to air dry for about a week to ensure there’s no moisture left. Then collect them in a container; they’ll remain viable for up to five years.