Radishes are easy to grow

Richard Bogren, Gill, Daniel J.

For Release On Or After 10/29/10

By Dan Gill
LSU AgCenter Horticulturist

Radishes are popular in cultures around the world. The flavor can be sharp and fresh or slightly sweet and mild, and they’re typically eaten raw. They are great on vegetable platters with dip or for just snacking. This is a great time to plant radishes in your garden, and no vegetables are easier to grow.

The radish belongs to the mustard, or Brassicaceae, family, which encompasses vegetables as diverse as broccoli and watercress. The small radishes we enjoy so much are known as Raphanus sativus, while the much larger oriental radishes are Raphanus sativus longipinnatus.

Radishes can be classified according to the length of their growing time from sowing to harvest. Short-season varieties mature quickly. They’re a joy for gardeners eager to have fresh vegetables for a fall salad because they’re ready to harvest in only 21 to 30 days. They require cool soil to germinate and mild air temperatures to develop well. They can be planted now through early April, although you may have to protect young plants from freezes in the teens. Varieties appropriate for Louisiana include Cherry Belle, Champion, Sparkler, Snow Belle, Easter Egg, French Breakfast and White Icicle.

Mid-season varieties were bred in Japan and are excellent for planting in February and March for May harvest. These large, carrot-shaped radishes grow more slowly and mature in 45 to 60 days. They have been bred to resist going to flower during warmer weather. Varieties for Louisiana include April Cross and Summer Cross.

Long-season radishes are much larger. They’re slower to mature – they take 50 to 70 days – than short season varieties. Long-season varieties need warm soil during germination and early growth, but short days and cool weather toward the end of their growing cycle. That makes them ideal to plant now for harvest this winter. Varieties include Misato Rose, Round Black Spanish, White Chinese, Sakurajima and German Beer.


A sunny location and a well-prepared bed with good drainage are the simple but important requirements for growing radishes. Radishes planted in heavy or clay soil will grow slowly and are likely to have misshapen roots. Most radishes, especially long-rooted varieties, will benefit from being in raised beds where deep, loose soil can be easily provided. To enrich the soil, add well-rotted compost or manure and work a general-purpose fertilizer into the soil before planting the seeds.

Don’t look for radish transplants at your local nursery. Radishes, like all root crops, are best grown from seed planted directly into the garden where they will grow. Sow seed at least one-half inch apart to a depth of one-quarter inch. Try not to sow the seeds too thickly. Cover the seeds lightly with fine soil, firm the soil in place gently, then water with a gentle spray. Radishes sprout in a matter of days, but they need a constant supply of water to do so. Check the soil daily during this period to assure it’s adequately moist.

Unless your family can consume a lot of radishes at one time, plan on sowing small amounts of seed every week or 10 days rather that raising one large crop. Radishes left in the ground past maturity become woody. Successive sowings guarantee a steady supply of young, fresh-tasting roots.


Plump, juicy radishes are those that grow quickly and continuously. A steady supply of water, at least an inch a week, will assure rapid, steady growth. Winter is usually fairly moist, but dry spells do occur. Water the plants when necessary. An organic mulch laid down when plants are 2 to 3 inches high will retain moisture and help keep the soil cool.

Thin radishes when the seedlings are an inch high so the plants will not crowd each other, and the small, thinned-out plants can be washed and added to salads. Plants in crowded beds will have abundant leaves but small roots. Short-season radishes need to be about 2 inches apart, while mid-season radishes require a minimum of 3 inches. The late-crop varieties need even more room; allow 4 to 8 inches between plants.


Start harvesting short-season varieties in three or four weeks when they are about an inch in size for best quality. Trim the leaves close to the top of the root. Then place them in a plastic bag and store them in the coolest part of the refrigerator where they’ll stay fresh-tasting for two to three weeks. Mid-season radishes will mature in five to six weeks, but they may be harvested as soon as they reach the size you prefer. Long-season types take more than two months to mature. They can be dug immediately or left in the ground for a few weeks.

Rick Bogren

1/4/2011 1:13:47 AM
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