|
back
| home
University
of Rhode Island GreenShare Factsheets
Potatoes
Potatoes tend to require more care and attention than
most other vegetables. The potato has specific soil requirements,
and thorough insect and disease control is necessary for potato
crops. A good yield is 150 to 175 pounds of usable potatoes
from 100 feet of row.
A well drained, fine sandy loam soil, high in organic
matter, is preferred. The use of manure, however, may increase
the incidence of potato scab.
If a cover crop (rye or wheat are excellent choices)
was planted the previous fall, it should be turned under before
it exceeds 12 inches in height by tilling 8 to 10 inches deep,
depending on the depth of the topsoil. After tilling, level
the surface slightly so furrows can be made. It is best to
wait at least a week after tilling in the cover crop before
planting the seed pieces.
Because scab disease (brown corky
tissue on surface of tubers) may be a problem in alkaline
or "sweet" soils, the
pH should be 5.0 to 5.5. Liberal amounts of fertilizer are
required for large yields of potatoes. Ideally, the fertilizer
should be placed in continuous bands two to three inches to
each side and slightly below the seed piece. However, many
gardeners will broadcast the fertilizer before tilling or spading.
Fertilizer rates should be based on results of a soil test;
a typical rate would be two and a half to three pounds of 8-16-16,
10-20-20 or equivalent per 100 square feet. When plants are
four to six inches tall, band two to three pounds of fertilizer
per 100 feet of row about 6 to 10 inches from the row, if growth
is not satisfactory and if foliage is yellowish-green.
Use only certified disease-free seed. Such seed is grown
under rigid rules and carefully inspected by state authorities.
The potato seed is not a true seed, but modified stem tissue
known as a tuber. The true seed of the potato occurs in the
small, inedible orange fruit the plant produces during mid-season.
Some feed and garden stores sell B-size seed-small tubers
weighing 1-1/2 to 2 ounces. These tubers should not be cut
before planting. If 4 to 6 ounce or larger tubers are used,
cut them so that each piece is block shaped, contains at least
one good eye or bud and weighs about 1-1/2 ounces. Plant immediately
after cutting.
Plant the seed in shallow trenches 3-1/2 to 4-1/2 inches
deep and cover with an inch or two of soil. The seed pieces
should be spaced 9 to 12 inches apart in rows 28 to 34 inches
apart. Nine to 12 pounds of seed will be needed for each 100
feet of row when 1-1/2 to 2 ounce seed pieces are planted 12
inches apart.
Control weeds by shallow and frequent
cultivation. Deep cultivation may cut potato roots and slow
growth. When plants
are 6 to 8 inches tall, begin to mound soil around the bases
of the plants to start forming a ridge or hill. By the time
the plants are 15 to 18 inches tall (at last cultivation),
the ridge or hill should be 4 to 5 inches high. "Hilling up" is
necessary to prevent greening of shallow tubers.
Flea beetles, leafhoppers, aphids and
Colorado potato beetles are the major insects affecting leaves
and stems. Early Blight and Late
Blight are the major foliar diseases of potatoes. See
GreenShare factsheets on these pests and diseases for specific
control recommendations.
Garden area previously in sod may harbor
wireworms, white grubs and other soil insects, which should be controlled
before planting potatoes.
For highest yields and best storage, potatoes should not
be dug until two weeks after vines have naturally died down.
This allows the skins to set and reduces skin peeling, bruising
and rot in storage.
When harvesting at temperatures above 80 degrees F, potatoes
should be picked up immediately and put in a dark place. Potatoes
exposed to sun and high temperatures will turn green and may
rot. Green skins on potatoes should be peeled off to reveal
white flesh before cooking.
Most homes do not have a suitable place to store potatoes
for more than four to six weeks. To store potatoes for several
months, the tubers should be cured in a dark place at 60 to
65 degrees F and a humidity of 85 percent or higher for 10
days. After the tubers are cured, keep them in a cool (40 to
45 degrees F), dark place with high humidity. Most varieties
will not sprout for two to three months under these conditions.
Adapted from E.C.
Wittmeyer, Marianne Riofrio and Mark Bennett, Ohio State
University Extension, 2000
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
|