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Chapter 28: Turnips and Radishes

Resource Guide for Organic Insect and Disease Management

28.1 Recommended Varieties, listed in approximate order of maturity.

Turnips Radishes
Purple Top White Globe
Just Right
Cherry Belle
Improved Red Prince
Scarlet Knight

28.2 Planting Methods

Turnips. The turnip is a cool-season, biennial, fresh-market vegetable that reaches the edible stage in 50 to 70 days. The tops are eaten as greens and the root as a fresh or boiled vegetable. Both white- and yellow-fleshed types are available, but white-fleshed varieties are more common. Best quality results when the crop reaches usable size under moderately cool temperatures.

Radishes. The common radish is a quick growing, annual, cool-season root vegetable. The seed germinates in three to four days at soil temperatures between 65° and 85°F and good moisture. Best quality and root shape are obtained when the crop grows and matures at moderate temperatures (50° to 65°F) in intermediate to short day lengths. Most varieties reach usable size in 23 to 28 days under favorable growing conditions, but in cold weather 40 to 50 days may be required.

Good quality radishes can be produced on either mineral or muck soil. Preferred planting dates are early spring and August, but suitable crops can be obtained from plantings made from April through August in certain sections of New York, particularly if soil moisture is adequate. Radishes remain in prime condition only a short time, especially in warm weather.

Table 28.2.1 Recommended spacing

Crop Row (inches) In-row (inches) Seed (lb/A) Depth (inches)
Turnip 14-18 2-3 1-2 0.5
Radish 8-15 1 10-15 0.5

Do Rotations Matter within Disease Management Programs?

28.3 Fertility

Maintain a pH of 6.0 to 6.5. Add one to two pounds of boron per acre with broadcast fertilizer. See Table 28.3.1, below, for the recommended rates of nitrogen, phosphorus, and potassium.

Table 28.3.1 Recommended nutrients based on soil tests

N pounds/acre P2O5 pounds/acre   K2O pounds/acre Comments
  Soil Phosphorus Level   Soil Potassium Level  
  low med. high   low med. high  
50 110 75 50   150 100 50 Total recommended.
50 110 75 50   150 100 50 Broadcast and disk-in. Sidedress at first cultivation.

28.4 Harvesting

Turnips. At maturity, turnips are usually two to three inches in diameter. Turnips are sold bunched or topped. They can be stored for several weeks at low temperatures (32° to 35°F) and high relative humidity (95 percent or above). With good air circulation, topped turnips can be stored four to five months.

Radishes. Radishes remain in prime condition for only a short time, especially in warm weather. Roots will become pithy if overmature. Most radishes are marketed with tops removed in plastic bags. Those sold with tops will lose moisture and quality more rapidly than those without tops. Radishes, like turnips, should be stored at 32° to 35°F and 95 to 100 percent relative humidity.

28.5 Disease Management

Under normal conditions, diseases are not a problem.

28.6 Insect Management

28.6.1 Cabbage Root Maggot
28.6.2 Flea Beetles
28.6.3 Swede Midge

28.7 Weed Management


Maintained by Abby Seaman, New York State IPM Program. Last modified 2019.