Midwest Vegetable Guide - 2022 - 256

Root Crops - Horticulture
Celeriac
This type of celery (Apium graveolens var. rapaceum) has
been bred as a root crop with low-growing bushy foliage and
a large, bearded, globe-shaped hypocotyl/root structure with a
celery flavor.
Start as transplants 8 to 10 weeks before planting, and plant
in early spring before last frost date. Transplant in rows 24 to
30 inches apart with plants 6 to 8 inches apart in row. For an
acre of transplanted celeriac, you will need 2 to 4 ounces of
seed to start in the greenhouse.
The full flavor is only reached after first frost. Time from
transplanting to harvest ranges from 80 to 90 days. From
seeding in cell trays, add 20 days.
Horseradish
This perennial Brassica (Armoracia rusticana) is grown
commercially in Illinois and Wisconsin as an annual crop
from root cuttings. The roots are not eaten raw, but grated as
a spice for condiments and flavoring. Type I varieties
produce large smooth roots and are highly resistant to turnip
mosaic virus and white rust. Type III varieties produce large
roots but are highly susceptible to those two diseases. Type II
varieties produce large roots with bark-like exterior, with
intermediate resistance to those two diseases. Numbered
commercial varieties are maintained by a small breeding
effort supported directly by the largest growers of the
commodity.
Plant root sets in early spring before last frost date. Sets
should be 1/2 to 3/4 inches in diameter and 10 to 16 inches
long. Root set ends that were closest to the plant (thicker end)
and the ends that were farthest from the plant (thinner end)
have to be planted thick end to thin end along the row, with
the thick ends elevated about 2 inches higher than the thin
end. This is accomplished by first scooping divots in rows 36
inches apart and 12 to 24 inches apart in-row. Then lay roots
by hand into the divots with the thin end in the deepest part.
That is roughly 10,000 sets per acre. Cover the roots with a
disc-hiller to a depth of 5 to 8 inches.
Horseradish plants put the most size on their roots in the late
summer and fall. Mechanical harvests with an undercutting
chain conveyor take place in November until freeze-up and
continues as soon as soils can be worked in the spring. Time
from transplanting to harvest ranges from 200 to 250 days.
Radish, Rutabaga, and Turnip
The roots of these Brassica plants are strong to mildlyflavored
and come in diverse size, colors, and shapes. For all
of these crops, the flavor is sweeter or milder when roots
reach marketable size in cool conditions.
Radishes (Raphanus sativus) come in globe-shaped bright red
varieties that are the most common in United States markets,
but market opportunities exist for the torpedo-shaped
varieties, as well as for white, black, yellow, green, pink and
deep red varieties. Most have white internal flesh, but some
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have pink internal flesh. Radishes become pungent during hot
weather. They can be direct-seeded in single rows 16 to 30
inches apart, or in three-row beds with 10 to 12 inches
between rows and 36 inches between beds, center to center.
Plant 12 to 15 per foot of row. Seed 10 to 15 pounds per acre.
Rutabagas (Brassica napus supsp. rapifera) are the largest
and mildest-flavored of these root crops. They are commonly
white or yellow skinned with white internal flesh. Some
develop a pink, purple, or green blush on the shoulders of the
root when exposed to the sun. They can be direct-seeded in
single rows 24 to 30 inches apart. Plant 3 to 4 seeds per foot
of row. Seed 1 to 2 pounds per acre.
Turnip roots (Brassica rapa subsp. rapa) are larger than a
radish, but smaller than a rutabaga, with a flavor that is an
intermediate intensity between radish and rutabaga. The
variety options are similar in appearance to rutabaga. They
can be direct-seeded in single rows 14 to 18 inches apart.
Plant 2 to 3 inches apart in row. Seed 1 to 2 pounds per acre.
Both mechanical and hand harvest is common and starts
when roots are of suitable size for the market. Time from
seeding to harvest ranges from 30 to 60 days for radishes and
turnips, or 80 to 100 days for rutabagas.
Fertilizing
pH: Maintain a soil pH of 6.0 to 6.8. For beets, maintain a
soil pH of 6.5 to 7.0.
Before planting, apply 60 pounds N per acre, 0 to 160 pounds
P2O5 per acre, and 0 to 200 pounds K2O per acre based on
soil test results and recommendations from your state.
For beets grown on sandy soils, light-colored silt and clay
loams, and alkaline, dark-colored soils apply boron at 2.5 to 5
pounds per acre applied over the row at planting. Do not let
boron contact seed. Beans, peas and cucurbits are sensitive to
boron so use caution if these crops will follow beets,
especially in the same season.
For carrots grown on muck soil with a pH greater than 6.0,
apply 6 pounds of manganese sulfate per acre applied over
the row at planting, or in a starter band.
For horseradish, add 1 to 2-1/2 pounds per acre boron and 15
to 25 pounds per acre sulfur with the initial N-P-K broadcast
application. An optional sidedress application of 50 to 75
lb/acre N can be made 8 to 12 weeks after planting, but
overapplication of nitrogen reduces root quality.
For most other root crops, sidedress with 30 to 60 pounds N
per acre 4 to 6 weeks after planting. Most radishes mature
quickly and do not require sidedressing. Reduce the amount
of fertilizer N applied by the value of N credits from green
manures, legume crops grown in the previous year, compost
and animal manures, and soils with more than 3 percent
Midwest Veg Guide 2022
Midwest Vegetable Guide - 2022

Table of Contents for the Digital Edition of Midwest Vegetable Guide - 2022
