January -
It is not too
early to start planning for this year's vegetable garden.
If you have
never grown potatoes, you might want to try it this year.
Potatoes are easy to grow and a fun and rewarding activity for
gardeners of all ages and experience levels.
It is
important to start with certified seed potatoes. Do not use
potatoes sold at grocery stores or ones from last year's garden.
Certified seed potatoes are disease- and insect-free, have not
been treated with a growth retardant, and are inspected by state
authorities. For the best selection, order from specialty
growers. See a source list at the end of the column.
Potatoes come
in many varieties, so have fun picking and choosing. There are
white-skinned, red-skinned, yellow flesh, purple skin with white
flesh, fingerling and others. Names you may recognize are 'Yukon
Gold' (white-skinned with yellow flesh), 'Purple Majesty'
(purple-skinned with white flesh), 'Viking' (red-skinned) and
'Irish Cobbler' (white-skinned). Some varieties are particularly
suited for baking or mashing while others are better for boiling
or roasting.

Another
factor to keep in mind when choosing a potato variety is whether
it is an early-, mid- or late-season variety. This refers to how
many days potatoes must grow before they reach maturity. This
can be anywhere from 75 days for early varieties to 135-160 days
for the late-season varieties.
As a general
rule, have your seed potatoes in hand 2-3 weeks before the
anticipated planting date. At this point, it's time to start the
process of chitting, or sprouting.
Place a
single layer of seed potatoes in a warm area (60-70 degrees)
with exposure to sunlight. Allow them to begin growing sprouts.
As they sprout, turn them to ensure that sprouts are green, not
white. Ideal sprout size for planting is about 1 inch. Chitting
will give you a one- to two-week jump-start on plant emergence.
Approximately
5-7 days before planting, cut the larger potatoes into two to
four block-shaped pieces. Each piece should contain at least one
sprout with plenty of tissue around it. Smaller, egg-sized
potatoes may be left whole. Allow the cut pieces to heal at room
temperature. The freshly cut surfaces will develop a protective
coating that will prevent decay.
Choose a
planting site in full sun with loose, well-drained soil. Compost
can be mixed well into the top 6-8 inches of soil to improve
drainage and moisture retention. If the potatoes are being
planted in an area not previously well fertilized, use a 5-10-10
fertilizer and apply at the rate of 5 to 6 pounds per 100 square
feet, or 33 feet of potato row, or use a balanced organic
fertilizer according to label directions.

Ideally, soil
pH is best kept around 5.5-6.0 to lessen the possibility of scab
disease, which can be a problem in alkaline soils. Scab will
show up as brown corky tissue on the potato surface. Precautions
should be taken with the use of manure and lime because both can
render the soil alkaline. Whenever possible, make all lime and
manure applications in the fall before planting.
Two weeks
before the last frost date, plant seed potatoes 3-4 inches deep,
sprout side up, and cover with 2 inches of soil. Seed pieces
should be 9-12 inches apart, with 34-36 inches between rows.
Water well after planting. If growing potatoes in containers,
choose a pot at least 15 inches in diameter and 15 inches deep.
Fill your container about one-third of the way with compost or
potting soil and plant prepared tubers.
When the
plants are 6-8 inches tall, begin hilling. Hilling is the
process of mounding soil around the base of the plant. It
provides plenty of loose soil for developing tubers and excludes
sunlight. Potato tubers exposed to sunlight will turn green and
become inedible and toxic to humans. A green potato indicates
harmful levels of solanine, a toxin natural to the potato.
If you are
growing your potatoes in containers, just add a few more inches
of soil to the pot as they grow, making sure the tubers are
fully covered. Do this 2-3 weeks after the first hilling and
then again in another two weeks. Many people also place straw on
top to block light.

Potato plants
need an average of 1-1.5 inches of water weekly until just
before harvest, and they may need to be watered during dry
periods. They produce a lovely flower, as well as a small,
round, green fruit. These fruits are not edible. They too
contain solanine and are not for human consumption. The fruits
do, however, contain the potato plant's true seed.
At about
10-13 weeks after planting, or when they flower, new potatoes
are ready to be dug up. New potatoes are the first potatoes that
the plant produces and will not be as large as the ones dug at
the final harvest. They should be about 1-2 inches in size and
are often used for soups, salads and roasting. If you choose to
dig up some new potatoes, be sure to leave plenty in the ground
to develop further.
Potatoes
should be harvested two weeks after the vines have naturally
died down. It's best to use a spade or a pitch fork and dig the
potatoes from the side of the soil hill, lifting them up from
underneath. Do this as carefully as you can, so as not to damage
them. It can be a fun activity for kids, like digging for buried
treasure.
Allow
harvested potatoes to dry for 3-4 days in a warm, shaded, airy
spot before storing them. Potatoes exposed to the sun and high
temperatures will turn green and may rot. If you are harvesting
potatoes at temperatures above 80 degrees, they should be picked
up immediately and put in a dark place. Make sure potatoes are
thoroughly dry before storing.
Optimum
storage conditions for potatoes are 35-40 degrees at moderate
humidity. Avoid locations where freezing will occur. Keep
potatoes in darkness and check periodically, removing any that
are not in optimum condition. Eating potatoes can be just as
much fun as growing them!
Sources:
Potato
Garden:
www.potatogarden.com or 1-800-314-1955
The Maine
Potato Lady:
www.mainepotatolady.com or 1-207-343-2270
Fedco Seeds:
www.fedcoseeds.com or 1-207-873-7333
LINKS
Potato Beetles
Master
Gardener articles