Radishes take many forms and are used in a large variety of ways world-wide. The common
red and icicle types are commonly used fresh as salad vegetables and garnish in the U.S.
Oriental types, such as the elongated and round daikon radishes, are less well-known in the U.S.
but are important staple foods in countries like Korea, Japan, Taiwan, and others in Asia, and by these ethnic groups
in the U.S. These types are used fresh, pickled (as is Kimchi), dried for future use, and cooked in countless
Oriental dishes. Seeds of radish are sprouted and these sprouts are another important food in these Aian countries.
Many varieties of radish exist. Some are unique novelties, others are popular for home
garden use, and still others are important in commerce. Most are adapted to production in
the Pacific Northwest. Only a few are listed below.
VARIETIES (approximately 30-35 days for bunching types).
Red: Cherry Belle, Fuego (multiple disease resistance for season long production). For trial:
Fancy Red (reported multiple disease resistance), Red King (reported resistant to club root and
Fusarium), Comet, Red Prince, Scarlet Knight, Red Boy, Champion, Inca, Cabernet, Cavalrondo.
White: Burpee White.
Icicle: Short Top, Icicle.
Daikon (approximately 60-70 days):
Elongated, slow bolting, all white types: Miyashige (try
also for late summer planting - fall harvest), Tokinashi, Tsukishi
Spring Cross, White Chinese or Celestial, All Seasons, and many others.
Novelty: Misato Green
(elongated, green-shouldered white exterior with greenish-white interior; Red
Coat (elongated, both skin and flesh are red).
Large Round types: Shogoin Round and many others (all white): Misato
Rose (white exterior
with pink flesh); Red Meat and Misato Red Flesh (both red flesh); Misato Red
(large round with
red exterior and white interior). Novelty, very large round: Sakurajima
Mammoth.
SOIL
Radishes do best on either light mineral soils or muck soils but may be
grown on a wide range on
soils. Daikon radish requires deep, friable soil for best quality roots.
SEED AND SEED TREATMENT
Radish seed numbers approximately 2,000-4,000 per ounce depending on
type and variety. Use
hot-water treated seed and fungicide treat seed to protect against several
serious seed borne
diseases. Hot water seed treatments are very specific (122 F exactly, for 25
to 30 minutes; the
wet seed then quickly cooled and dried). The seed treatments are best done by
the seed company,
and can usually be provided upon request.
SEEDING
Important: Before planting this Crucifer crop, consider the following
important factors:
1. No crucifer crop, or related weed has been present in the field for
at least 2 years, 4 years
preferable. Crucifer crops include cabbage, cauliflower, broccoli, kale,
kohlrabi, Brussels sprouts,
Chinese cabbage, all mustards, turnips, rutabagas, radishes etc. Cruciferous
weeds include wild
radish, wild mustards etc. Also, crucifer plant waste should not have been
dumped on these
fields.
2. Soil pH should be 6.5 or higher. Soil pH over 6.8 is necessary to
manage club root. The
application of 1500 lb/acre of hydrated lime, 6 weeks prior to planting is
recommended for soils
with pH less than 7.5 for club root control when planting club root
susceptible radishes.
Use a drill with a 2 or 4-inch scatter shoe to drop 24 seeds 1/2 inch
deep per foot of row. Space rows 8 inches apart.
Oregon growers commonly apply a mixture of sawdust and chicken manure to a depth of 1/4 to 1/2 inch
over the planted beds.
Daikon in-row spacing should be 4-6 inches, with rows 24-36 inches
apart. Adjust planting rates
accordingly. Some Chinese radishes can weigh 100 lbs. These would be spaced
24-36 inches apart in rows 36-48 inches apart.
FERTILIZER
A soil test is the most accurate guide to fertilizer requirements. The
following recommendations are general guidelines.
Maintain a pH 6.5-7.0, adding lime or dolomitic lime (if magnesium is
needed) as indicated by soil test.
For red globe radish, poultry manure is often used to supply 50-75 lb N/acre.
Care is needed to guard against excessive top growth. Excessive N is
particularly bad during periods of warm, wet weather. Buildup of soil N during the season
results in progressively larger tops, so N applications should be reduced as the season progresses.
Add P and K as indicated below.
Nitrogen rates for Daikon radish should be 130-150 lb/acre. Divide this among
several
applications, applying two thirds of the total during the last half of the
growth period. Adjust N rates and irrigation as necessary to maintain vigorous, uniform
growth.
In the absence of a soil test, for both red globe and daikon radish, P,
K, S and B, should be applied as follows:
Phosphate: 130-150 (P2O5) lb/acre
Potash: 100-150 (K2O) lb/acre
Sulfur: 30-50 lb/acre per season
Boron: 1-5 lb/acre, or as needed according to soil test.
If fertilizer is to be banded at time of seeding, rates greater than 60
lb/acre of potash should be broadcast and incorporated before seeding.
IRRIGATION
Globe radishes are shallow rooted and quick growing, requiring frequent,
uniform irrigation for
optimum growth and tenderness. Earliest plantings may receive sufficient rain
to mature the crop,
later plantings may need a total of 5-6 inches of water depending on planting
date, seasonal
variation, and variety. Use care to prevent excessive top growth.
Daikon radishes require full season to reach maturity, and 12-15 inches
of water under western
Oregon conditions. For best root quality, irrigate to maintain uniform,
vigorous growth.
Soil type does not affect the amount of total water needed, but does
dictate frequency of water
application. Lighter soils need more frequent water applications, but less
water applied per
application.
HARVESTING, HANDLING, AND STORAGE
The University of California-Davis has a file on Minimal
Processing of Fresh Vegetables that discusses film wrapping and other topics.
Red radish may yield up to 800 cartons/acre per crop.
Three or four crops may be obtained per season on the same ground. Daikon radish yields would be
approximately 15-20 tons/acre.
All harvesting is done by hand. Red radishes are pulled and tied in bunches.
The bunches are washed and should be cooled immediately after harvest for best shelf life.
Bunches are packed either 2 or 4 dozen/carton. About 90 percent are currently packed in 4-dozen
cartons. The 2-dozen cartons are mostly used for shipments to California. Average yield of the
4-dozen cartons is 500-800/acre.
Radishes should be kept moist and cool at all times to prevent dehydration. Daikon radish may be
mechanically undercut before harvest.
STORAGE (Quoted or modified from USDA Ag. Handbook 66 and other sources)
Hold radishes at 32 F and 95 to 100% relative humidity. Most spring
radishes are topped and
packaged in plastic bags. They should be cooled quickly to 40 F or below to
maintain their
crispness. Hydrocooling is an effective method of cooling radishes. Black
spot is reduced by
washing radishes in chlorinated water. Topped radishes can usually be held
for 3 to 4 weeks at 32
F and a somewhat shorter time at 40 F. They will keep at least a week at 45
F. When
temperatures are higher than 32, low oxygen (1%) is beneficial in reducing tip
and root growth
and softening. The regrowth of tops can be greatly retarded by trimming off
the growing points,
which are aggregated within a few millimeters on to of the root.
Bunched radishes have a much shorter market life because of the
perishability of the tops. They
can be held at 32 F and a relative humidity of 95% for 1 to 2 weeks. Addition
of package and top
ice aids in keeping the tops fresh.
Daikon, Chinese, or black, radishes require the same storage conditions
as topped carrots and
should keep in good condition for 2 to 4 months at 32 F.
PACKAGING
Topped radishes are commonly packed in 15-lb cartons containing 30 film
bags each 6 ounces
(Florida); 11.5-lb cartons of 30 film bags each 6 ounces (California) or 25-lb
loose packed film
bags.
Bunched radishes are packed in cartons of 24-48 count bunches of 6-9
radishes per bunch.
Daikon may be marketed in cartons or 20-lb plastic bags.
Return to: | Beginning of This File | Index to Vegetable Production Guides |
|