VARIETIES (approximately 55-65 days).
Grand Duke, Kolibri F1 (purple), White Vienna. For trial: Gigante, Granlibakken,
Purple Danube, Purple Vienna, Rapidstar, White Danube.
All kohlrabi is direct-seeded. Kohlrabi seed numbers approximately
144,000 per pound. Use hot-water and fungicide-treated seed to protect against several serious
seed-borne diseases. Hot water seed treatments are very specific (122 F exactly, for 25 to 30 minutes.
Seed must then be quickly cooled and dried). The seed treatments are best done by the seed
company, and can usually be provided upon request.
Use 1-2 lb seed/acre. Seed in early April to
early May or July and August to avoid harvest during the hottest part of the summer since hot
weather may produce inferior bulbs. Use only treated seed. Sow the seed 0.5 inches deep.
Spacing between rows should range from 12-20 inches. Thin plants to 3-4
inches apart within the row.
It is recommended to do a soil test for each field to be planted. The
following rates are general recommendations only. A more complete guide to fertilization and lime
requirements of kohlrabi and other cole crops may be found in Broccoli.
Nitrogen: 100-125 (N) lb/acre.
Phosphorus: 100-150 (P2O5) lb/acre, or more, depending on soil
Potassium: 100-125 (K2O) lb/acre, or more, depending on soil test.
Magnesium: 15-25 (MgO) lb/acre.
Sulfur: 30-50 lb/acre.
Copper, zinc and boron - as indicated by soil test.
Maintain uniform soil moisture for highest quality product. A total of
8-12 inches of water may be needed. 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 AND HANDLING
Kohlrabi yield is approximately 120-160 cwt/acre. It is very important
to harvest spring-sown kohlrabi when they are small. They will get larger than tennis balls in fair
soil, but by this time they are of very poor quality. To get tender, sweet kohlrabi, pick them when
they are less than 2-2.5 inches in diameter. Fall-grown kohlrabi is less likely to get woody and
may remain at good quality until Christmas when it is 4-5 inches in diameter.
STORAGE (Quoted or modified from USDA Ag. Handbook 66 and other sources)
Store kohlrabi at 32 F and 98 to 100 % relative humidity. Topped
kohlrabi should keep for 2 to 3
months if stored under the recommended conditions. Some space between
containers for air circulation is desirable, and a high relative humidity is recommended to
prevent shriveling and toughening of texture. Packaging in perforated film can be used to reduce
moisture loss. Kohlrabi with leaves has a storage life of only 2 weeks at 32 F.
Storage should be at or near 32 F to prevent the development of
diseases. Major storage diseases are bacterial soft rot and black rot.
Kohlrabi is commonly packaged in 25-lb film bags; 50-lb film and
mesh bags; or 24-lb cartons, holding 24 film bags, weighing 1 pound each.
WEED AND DISEASE CONTROL FOR KOHLRABI
THE PESTICIDES LISTED BELOW ARE FOR INFORMATION ONLY AND ARE REVISED ONLY
ANNUALLY. BECAUSE OF CONSTANTLY CHANGING LABELS, LAWS, AND
REGULATIONS, OREGON STATE UNIVERSITY CAN ASSUME NO LIABILITY FOR
THE CONSEQUENCES OF USE OF CHEMICALS SUGGESTED HERE. IN ALL CASES,
READ AND FOLLOW THE DIRECTIONS AND PRECAUTIONARY STATEMENTS ON
THE SPECIFIC PESTICIDE PRODUCT LABEL.
USE PESTICIDES SAFELY!
Wear protective clothing and safety devices as recommended on the label.
Bathe or shower after
Read the pesticide label--even if you've used the pesticide before. Follow
closely the instructions
on the label (and any other directions you have).
Be cautious when you apply pesticides. Know your legal responsibility as a
You may be liable for injury or damage resulting from pesticide use.
Note that Oregon law requires that agricultural pesticide use be reported to the Oregon Dept. of Agriculture
under its on-line PURS system.
The Pacific Northwest Weed Control Handbook has no control entries for
this crop. Cultivate as often as necessary when weeds are small. Proper cultivation, field
selection and rotations can reduce or eliminate the need for chemical weed control.
See the Pacific Northwest Weed Management Handbook for an
explanation of the use of stale seedbeds for vegetable production.
Herbicides registered for use on kohlrabi, but not evaluated by University personnel in the Pacific Northwest,
include DCPA, sethoxydim, and glyphosate (stale seedbed technique only). Check herbicide labels for rates, restrictions, and weeds controlled.
The Pacific Northwest Disease Control Handbook has no control entries for
this crop. Proper
rotations, field selection, sanitation, spacings, fertilizer and irrigation
practices can reduce the
risk of many diseases. Fields can be tested for presence of harmful
nematodes. Using seed from
reputable sources reduces risk from "seed-borne" diseases.
Among fungicides registered, but not evaluated by University personnel in the Pacific Northwest,
are Aliette, Maneb, and Telone. Check fungicide labels for rates, restrictions, and diseases controlled.
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