Eat radishes when picked for best texture.
Radish is a cool-season, fast-maturing, easy-to-grow vegetable. Garden radishes can be grown wherever there is sun and moist, fertile soil, even on the smallest city lot. Early varieties usually grow best in the cool days of early spring, but some later-maturing varieties can be planted for summer use.
The variety French Breakfast holds up and grows better than most early types in summer heat if water is supplied regularly. Additional sowings of spring types can begin in late summer, to mature in the cooler, more moist days of fall. Winter radishes are sown in midsummer to late summer, much as fall turnips. They are slower to develop than spring radishes; grow considerably larger, remain crisp longer, are usually more pungent, and hold in the ground or store longer than spring varieties.
When to Plant
Spring radishes should be planted from as early as the soil can be worked until mid-spring.
- Make successive plantings of short rows every 10 to 14 days.
- Plant in spaces between slow-maturing vegetables (such as broccoli and brussels sprouts) or in areas that will be used later for warm-season crops (peppers, tomatoes, and squash).
- Spring radishes also can be planted in late winter in a protected cold frame, window box, or container in the house or on the patio.
- Later-maturing varieties of radishes (Icicle or French Breakfast) usually withstand heat better than the early-maturing varieties and are recommended for late-spring planting for summer harvest.
- Winter radishes require a much longer time to mature than spring radishes and are planted at the same time as late turnips (usually midsummer to late summer).
Spacing & Depth
- Sow seed 1/4 to 1/2 inch deep.
- Thin spring varieties to 1/2 to 1 inch between plants.
- Winter radishes must be thinned to 2 to 4 inches, or even farther apart to allow for proper development of their larger roots.
- On beds, radishes may be broadcast lightly and thinned to stand 2 to 3 inches apart in all directions.
Radishes grow well in almost any soil that is prepared well, fertilized before planting, and has adequate moisture maintained. Slow development makes radishes hot in taste and woody in texture.
Radishes mature rapidly under favorable conditions and should be checked often for approaching maturity. Harvest should begin as soon as roots reach edible size and should be completed quickly before heat, pithiness, or seed stalks can begin to develop.
Root maggots may tunnel into radishes. These insects are more common above 40 degrees north latitude. Apply a suggested soil insecticide before planting if this insect previously has been a problem.
Pull radishes when they are of usable size (usually staring when roots are less than 1 inch in diameter) and relatively young. Radishes remain in edible condition for only a short time before they become pithy (spongy) and hot. Proper thinning focuses the harvest and avoids disappointing stragglers that have taken too long to develop.
Winter varieties mature more slowly and should be harvested at considerably larger size. Once they reach maturity, they maintain high quality for a fairly long time in the garden, especially in cool fall weather. Size continues to increase under favorable fall conditions. Daikon or Chinese radish, can achieve particularly large size and still maintain excellent quality. Winter radishes can be pulled before the ground freezes and stored in moist cold storage for up to several months.
Selection & Storage
Radishes have often been dismissed as decoration and garnish. They are members of the cruciferous vegetable family. so eat the greens. Because they vary in keeping quality, radishes are classified as winter or summer.
Summer radishes are the small ones of bold red, pink, purple, white, or red and white. They may be globe-shaped or elongated, fiery hot, or mild.
- Harvest summer radishes when they are small and tender for optimal flavor.
- Oversize summer radishes can become tough, woody, hollow, and strong in flavor.
- To check a large radish squeeze gently, if it yields to pressure it is likely to be fibrous. These will do well in the compost heap.
Harvest winter radishes when they are large and mature.
- Winter radishes may be white, black, or green.
- Black radishes have a pungent flavor and should be used sparingly. Remove greens and roots before storing black radishes.
- Chinese radishes, round and fat, are milder in flavor. Remove greens before storing; remove roots just before preparing.
The word daikon means "great root" in Japanese. In cool weather, daikon growth is quick and steady. The fully mature daikon can grow up to about 18 inches long and weighs 5 or 6 pounds. There are several varieties. Some are thin and long, while others are short and round.
All radish greens are edible.
Save the young thinnings of both summer and winter radishes. They are delicious with tops and bottoms intact. Both summer and winter radishes store well in the refrigerator once the tops have been removed. The radish leaves cause moisture and nutrient loss during storage. Store greens separately for 2-3 days. Refrigerate radishes wrapped in plastic bags for 5 to 7 days. Winter radish varieties can be stored for up to two weeks in the refrigerator.
Questions and Answers
Q. What causes my radishes to crack and split?
A. The radishes are too old. Pull them when they are younger and smaller. A flush of moisture after a period of relative dryness also may cause mature roots to burst and split. Try to avoid uneven moisture availability.
Q. Why do my radishes grow all tops with no root development?
A. There may be several reasons: seed planted too thickly and plants not thinned (though some roots along the outside of the row usually develop well even under extreme crowding), weather too hot for the spring varieties that do best in cool temperatures (planted too late or unseasonable weather) and too much shade (must be severe to completely discourage root enlargement).
Q. What causes my radishes to be too "hot"?
A. The "hotness" of radishes results from the length of time they have grown rather than from their size. The radishes either grew too slowly or are too old.