| Radish |
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Radish is a cool-season root crop that matures to marketable size in 24 to 30 days under favorable weather conditions. The best quality roots are produced in spring or fall when temperatures are in the range of 50°F to 65°F, when daylength is short to moderate, and when grown with ample moisture. As temperatures increase and as the days become longer during summer (>15 hours), radish tends to bolt (go to seed) and the roots become pithy and pungent. To minimize the adverse effects of summer, maintain a high level of soil moisture. Varieties
Spacing and SeedingSeed radish 1/4” to 1/2” deep, spaced at 3/4” to 1” apart within the row (to obtain 12 to 15 plants per foot of row). Space rows 8” to 15” apart. In the spring, plant as soon as the soil can be worked; thereafter, plant at intervals of about 10 days. Radishes are often planted in 4’-wide raised beds, 6 rows per bed. LimeApply lime according to soil test results to maintain soil pH at 6.5 to 6.8. FertilizerLess nitrogen fertilizer will be needed if manure or legume sod was plowed down (see nitrogen credits).
Weed ControlSee section on Soil Fumigation. Proper use of Vapam can provide weed control and will be more economical if multiple plantings are used. NOTE: For the herbicides listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, days to harvest (dh), REI, and special instructions. In many cases there are other products available with the same active ingredient. Please see Table 17 and Alphabetical Listing by Trade Name for more information on products with the same active ingredients. Stale Seedbedglyphosate (Roundup 4S): 1 to 5 qt/A (REI 12h, Group 9). See Stale Seedbed Technique. Soil Appliedtrifluralin (Treflan HFP): 1 to 1 1/2 pt/A (REI 12h, Group 3). Incorporate before planting. Disc twice immediately after spraying for satisfactory incorporation. Little or no control of ragweed, galinsoga, or nutsedge. Postemergenceclethodim (Select 2 EC): 6 to 8 oz/A (15 dh, REI 24h, Group 1). Apply to actively growing grasses. See label for grass height and herbicide rate. Always use a crop oil concentrate at a rate of 1 gal/100 gal spray mix. See both container label and supplemental label available from dealer. Insect ControlNOTE: For the insecticides listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, days to harvest (dh), REI, and special instructions. In many cases there are other products available with the same active ingredient. Please see Table 20 and Alphabetical Listing by Trade Name for more information on products with the same active ingredients. Cabbage MaggotNonchemical control: The cabbage maggot can be controlled with spunbonded row covers. Cover at seeding and seal the edges with soil to exclude the cabbage maggot fly which lays eggs at the base of young radish seedlings. Do not plant into land that was planted to a cole crop the previous year as this pest overwinters as pupae in soils where larvae infested plants. CutwormsCaterpillars hide under the soil surface adjacent to the plant stem during the day and feed on stems after dark. For best results, make application between midnight and dawn while cutworms are feeding aboveground. Synthetic pyrethroids (Group 3A) may work best during cool spring weather. See cutworms in the Pepper and Tomato (Outdoor) sections for more information on the black and variegated cutworms. Bacillus thuringiensis kurstaki (Dipel DF): 0.5 to 1 lb/A (0 dh, REI 4h, Group 11). Must be ingested; apply in evening before larvae are actively feeding and direct sprays to base of stem. Use high rate at cool temperatures. OMRI listed. carbaryl (10% Sevin Granules): 20 lb/A (3 dh fresh, 21 dh dry, REI 12h, Group 1A). Apply evenly over soil surface. pyrethrins + piperonyl butoxide (Pyrenone): 1 tsp/gal, or 1 to 12 oz/A (0 dh, REI 12h, Group 3A). Flea BeetleSee Cabbage Section for more details on flea beetles in Brassica crops. beta-cyfluthrin (Baythroid* XL): 1.6 oz/A (o dh, REI 12h, Group 3A). carbaryl (Sevin XLR Plus): 1/2 to 1 qt/A (7 dh, REI 12h, Group 1A). spinosad (Entrust): 1 to 2 dry oz/A (3 dh, REI 4h, Group 5). OMRI listed. Disease ControlNOTE: For the products for disease control listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, days to harvest (dh), REI, and special instructions. In many cases there are other products available with the same active ingredient. Please see Table 22 and Alphabetical Listing by Trade Name for more information on products with the same active ingredients. Seed DecayBuy treated seed. Do not use treated seed for food, feed or oil purposes. Alternaria leaf spotAlternaria leaf spot does not affect the root but will reduce the value of fresh-packed plants that retain the foliage. Buy certified disease-free seed or hot-water treat seed. Reduce cruciferous weeds and plow under crop debris in the fall. Rotate with noncruciferous crops. pyraclostrobin (Cabrio EG): 8-12 fl oz/A. (0 dh, REI12h, Group 11). Do not alternate with Group 11 fungicides such as Quadris. Downy Mildew (Hyaloperonospora parasitica)This disease occurs worldwide, affects most crucifers, and is most important at the seedling stage. It is an important pathogen on radish because it can infect the fleshy root, causing external black patches, lesions on the root shoulder, and internal grey or black flecking and streaking. The root surface is scarred, prone to cracking or splitting, and unmarketable. Manage Downy mildew on transplants by improving air circulation and irrigating early in the day so plants can dry quickly. Plant resistant or tolerant cultivars. White Rust, White blister (Albugo candida)Yield reductions are rare but quality is reduced by the prominent signs of the pathogen. On radish, white rust can also infect flower shoots and cause root swellings. Use resistant cultivars where available and rotate to non-hosts where the disease is common. Proper fertility levels, especially of phosphorous and potassium, have been reported to reduce disease. |
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