(See also file on Radicchio)
The terms "chicory" and "endive" are frequently interchanged because the "forced" product of
Witloof chicory has been erroneously named French or Belgian endive. This information deals
with the production of the forced Witloof chicory for chicons (4-6 inch, spindle-shaped heads or
buds). Other synonyms are White Endive and Dutch chicory.
Another type of chicory, whose dried roots are used as a coffee substitute, is Magdeburgh or
Italian Dandelion. Tops may also be used in cooking like spinach. The field production phase of
both these types may be handled similarly.
Recently, chicory root is being considered as a natural source of fructose oligosaccharide, a
zero-calorie sweetener. Washington State University information indicates that the Pacific
northwest regions west of the Cascade Mountains may be ideally suited for its production.
VARIETIES OF WITLOOF CHICORY
Variety results from Connecticut indicate the following:
Early to mid winter forcing: Zoom.
Late (forcing through March): Flash.
For trial: Magnum.
Witloof chicory must be planted in friable soils, that would otherwise be suitable for carrot
production. The use of raised beds greatly improves root quality for forcing.
Loose fertile loams, and muck soils are best. Soils should provide good water holding capacity
and good internal drainage, and a pH of 6.5 and above. Since roots of Witloof are harvested in
the fall, soils should be chosen that allow harvest in moderately rainy conditions.
SEED AND SEED TREATMENT
Witloof seed numbers approximately 25,000 per ounce. Use a fungicide treated seed whenever
possible. Have germination checked before planting if germination value is not known or current.
Pelletizing seed allows precision planting. Plant as shallow as possible, commensurate with soil
and moisture conditions. One and a half to 2.5 lb of raw seed are required per acre. With graded
and pelletized seed, 250,000 pellets are used per acre. These are thinned to the spacings indicated
SEEDING AND SPACING
Witloof performs best under cool temperatures and requires 110 to 130 frost free days in order to
produce roots of desirable size for forcing.
Witloof varieties are planted beginning in April, ending in May. March plantings would need to
be covered with plastic to prevent premature bolting (seed stalk development). These are dug
from August through October for forcing.
Witloof is planted at spacings of 4-6 inches in the row with rows 18-24 inches apart. This
produces populations of from 30,000 to 80,000 plants per acre. Select spacings and row
arrangements that allow use of small carrot or potato diggers for harvesting roots for forcing.
Uniformity of spacing is important since this influences the size of chicons produced.
Nitrogen: Do not use more than 50 lb N per acre. Excessive nitrogen produces heavier
tops at the expense of good roots.
Phosphorus: 100-150 (P2O5) lb/acre - apply all at time of seeding or transplanting preferably
banded 2 inches to the side and 2 inches below the seed or plant roots.
Potassium: 50-150 (K2O) lb/acre - broadcast prior to planting.
Sulfur: 20-30 (S) lb/acre - broadcast prior to planting.
These recommendations are intended to provide adequate fertilizer. Nitrogen rates especially may
need to be adjusted depending on crop, planting date, weather conditions and soil type.
These crops require a uniform supply of water for tender growth. Frequent irrigations are
preferred because these crops are shallow rooted. A total of 12-14 inches of water may be
necessary depending on seasonal variation, variety and planting date.
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
HARVESTING FOR FORCING
Witloof chicory is harvested from the field after about 130-150 days, when roots are of
adequate size. Roots may be dug for forcing from September through November. Do not harvest
after the end of November because vernalization may have occurred and may result in bolting.
Maturity of roots can be judged by examining a vertical section cut through the crown. When a
white section about the size of a fingernail (1/4 to 3/8 inch thick) is present just below the crown
section, the root is ready for harvest and forcing. When this white tissue is less than 1/4 inch
thick, the roots are immature and will not produce tight chicons. When larger than 3/8 inch,
numerous, mostly unmarketable chicons may form. Roots should be 1 1/4 to 2 1/2 inches in
diameter. Harvest as follows:
1. Undercut and loosen roots with a bar blade, and allow roots to cure in the field for 3 or 4 days.
Do not allow roots to be exposed to sunlight.
2. Cut tops 0.5 to 1 inch above the shoulders of the roots. Remove as much of the top as possible
without injuring the growing point. Failure to remove enough of the tops can result in decay
during forcing. Tops may mechanically removed just prior to undercutting if this can be done
without damage to the growing point.
3. After loosening roots, roots may be hand harvested, or dug with potato equipment or carrot
equipment after the tops are removed.
4. Sort roots by diameter. Roots about l l/2 to 2 1/2" in diameter are ideal.
FORCING, HARVEST, AND HANDLING
Roots are cut to a length of 6-9 inches and packed upright, tightly, in bins that are about 12 to 15
inches deep, with soil or a hydroponic solution. Both circulating and non-circulating hydroponic
systems are used. Roots are forced in darkness in cellars or forcing rooms. A temperature of
32-34 F is used for holding and 50-60 F temperature is used for forcing. Ideally, air temperature
should be 5 F cooler than the root temperature during forcing. To accomplish this, some forcing
rooms are designed with hydroponic trays into which the roots are placed and through which
water at a temperature of 60-70 degrees is circulated. Air temperature is maintained at 55-65 F
using appropriate refrigeration equipment. Hydroponic trays are usually stacked in frames,
allowing the necessary space between trays for harvest.
Forcing rooms should be kept at 90% or more relative humidity. At the proper temperature 3-4
weeks are necessary for proper chicon development.
Chicons are cut or snapped from the roots and any loose outer leaves removed. They should be
4-6 inches in length, compact and spindle-shaped. Chicons 2-3 ounces each, and free of green
color, are most desirable. They must be handled carefully to avoid abrasion and mechanical
damage. From each 100 lb of roots being forced, about 15-20 lb of Witloof chicons may be
Vernalization temperatures prior to forcing affect chicon quality (sugars and shape), with greater
vernalization producing longer chicons.
STORAGE (Quoted or modified from USDA Ag. Handbook 66 and other sources)
Cool product as quickly as possible. Witloof should not be wetted. Store cartons in a cold, room
at 34-36 F and 95-98% relative humidity.
This bullet-shaped salad vegetable should keep 2 to 4 weeks at 34 to 36 F with high relative
humidity. Compact chicons 4 to 5 inches in length are most desired. This vegetable is mainly
imported by air from Europe. Over-wrapping with perforated plastic film is beneficial. In
marketing, blue paraffin paper may be used for protection against light and moisture loss. Leaves
should be white with slightly yellow tips.
Deterioration shows as marginal leaf browning after 2 to 4 weeks at 36 F, 1 to 2 weeks at 40 F,
and 1 week at 60 F. Holding witloof chicory in 3 to 4 % oxygen with 4 to 5 % carbon dioxide at
32 F about doubles its useful life compared to storage in air. This controlled atmosphere delays
greening of the tips of the leaves in light and opening of the chicons.
All these crops are packaged in cartons containing 10-20 lb, depending on the item. Consult
buyers for preferred packaging, and container sizes. Package Witloof chicons in cartons lined
with blue moisture proof paper to exclude light and retain moisture.
PEST CONTROL FOR WITLOOF
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. Stale seedbed techniques employing flaming may be used.
The Pacific Northwest Insect Control Handbook has no control entries for this crop. Lannate is registered but has not been evaluated
in the Pacific Northwest. Consult label for rates, restrictions, and insects controlled.
Proper rotations and field selection can minimize problems with insects.
The Pacific Northwest Disease Control Handbook has no control entries for this crop. Ridomil is registered but has not been
evaluated in the Pacific Northwest. Consult label for rates, restrictions, and diseases controlled.
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.
Choose fields free of perennial weeds and where related crops have not been grown for the
previous three years to minimize problems with diseases and weeds.
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