University of Vermont Extension
Department of Plant and Soil Science
YOUR OWN POTATOES
Leonard Perry, Extension Professor
University of Vermont
In a recent
survey of Vermont gardeners, only about one third grew their own
potatoes. Yet this vegetable is easy to grow by several
methods, and following a few tips.
Growing your own you can have varieties that you wont find
with better flavor, and ones that you know are safe to eat.
in large fields, growers can be faced with several problems that
control with chemicals. This gives store
potatoes a listing on the “dirty dozen”—those vegetables reported to
most pesticide residues (www.ewg.org).
buying from local organic farmers you can avoid such concerns, but
may use organic chemicals you wouldn’t need in a home garden.
are so many varieties, too, that you just won’t find in stores or
many local growers. Potatoes can be
grouped by use, size, or color and vary in texture and flavor. The
russet types are ones you see in stores
with the brown skin, large elongated shape, and are used for
baking. “New” potatoes are ones harvested small and
immature, and aren’t necessarily red as often believed. Red
potatoes (on the outside) can be red,
white, or yellow on the inside. White
potatoes (on the outside) can be white or yellow inside. Then there
are purple potatoes, both outside
and inside, which may turn blue on cooking.
Finally there are the fingerlings, shaped more like fingers or
can be grown from true seeds, similar to tomatoes, in which case
you’d want to sow them indoors about 8 weeks before the last frost
date when you’d plant outside. Usually though they are grown from
“seed potatoes” which
aren’t seeds but pieces of a potato with sprouts, buds, or “eyes”.
You’ll find these in garden catalogs and
stores in spring, but not on the seed racks! Look for certified
potatoes. Don’t use store potatoes, as
these usually have been treated with an inhibitor to prevent
might have diseases.
are a storage organ of the plant called a “tuber”. For golf-ball
sized tubers of seed potatoes,
you can plant them directly. Large
tubers should be cut into pieces about 2-inches thick, or weighing
ounces, and containing a couple of the new shoots or eyes. These
should still be short, just sprouting,
and not with stems on them yet. If they
have started growing, handle very gently to avoid breaking these
stems. If cutting a large tuber into sections,
before planting allow the pieces to harden-off in a cool (55 to 65
well-ventilated area for a day or two.
outside about 3 weeks before the last frost date, about the time
blooming and soil temperatures are at least 50 degrees (F). While
frost won’t hurt the seed pieces in the
ground, it can damage new shoots above ground.
Cover these with a frost cloth or similar protection if needed.
principle to keep in mind when planting is that you want the new
that form to be in the ground, out of the light, so they don’t turn
makes them bitter and slightly toxic).
There are several methods of keeping
them in the dark under soil.
Traditionally, seed potatoes are planted about 3-inches deep in
trenches, about a foot apart, and with rows about 3-feet apart.
Then, as the plants grow, you mound or “hill”
up soil (or compost or straw) around them, covering about half to
the plant. If using the straw method,
first cover with a couple inches of compost before applying
layers. Straw may
not be good to use if you have mice in your yard or
nearby, and may result in lower yields.
variation on straw hilling begins with a foot-deep trench, planting
potatoes in the bottom about three inches deeper. As plants grow,
first add a few inches of
compost, then just straw, filling in the trench.
on space? Don’t want to go on a treasure
hunt digging later in summer? Or do you
only have full sun, which they need, not where you might plant in
ground? Then consider planting in
containers. This is the method I use,
with potatoes growing in thick felt-like bags just for growing such
crops. Although bags hold about 15 gallons of mix, I
only use about 12 gallons. I start with
about 6 to 8 inches of a compost and potting soil mix, then as the
add more until the bag is about 3/4 full.
A square wooden frame or wire mesh cage could be used similarly.
a low pH or acidic soil is recommended by some to avoid scab
often grow well over a range from 5.0 to 6.5, with 5.5 to 6.0
perhaps ideal. Soils should be well-drained and not
soggy. Potatoes need some fertility, but
not too much, which will result in mainly leaves and shoots. In a
fertile soil, compost may be all that is
needed. Avoid manures as these can lead
to scab. Otherwise, add a garden
fertilizer according to soil test recommendations. Lacking these,
you might broadcast over the
bed and mix in a quart of 5-10-10 fertilizer per 25 feet of row. A
main key to good yields is keeping plants
well-watered, especially after bloom until shortly before harvest,
tubers are forming. Mulches help.
main disease with potatoes is a bacterial one called “scab” from the
of the corky dark lesions on the surface.
Potatoes are still edible but must be peeled. As already noted,
avoiding manures and
alkaline soils help to prevent this organism from growing, as does
watering. Avoid planting potatoes in the
same spot for three years (called “crop rotation”), or where other
such as carrots, beets, and turnips have been planted. Some
varieties that are resistant to scab
include Russet Burbank, Norgold, Red Norland, and Superior.
disease potatoes can get, and in fact spreads to related crops, is
blight. This is the famous disease of
the Irish potato famine of the 1840’s.
Crop rotation helps with it, as well as other diseases, including
planting in the same area as tomatoes, peppers, eggplants, and
three years. Don’t leave any tubers in
the ground or save them from previous years if late blight has been
use certified disease-free seed potatoes.
There are sprays for this disease, including organic ones.
main insect of potatoes in general is the pretty, somewhat rounded
potato beetle. Watch for it soon after
the first leaves emerge, and handpick off.
Look under leaves for clusters of the bright orange eggs, and
these as well. These hatch the larvae
that eat the leaves. Covering plants
with floating row covers (very thin fabrics sold as this) goes a
long way to
keeping this beetle away, as well as other insects such as
beetles, and aphids.
You can harvest “new” potatoes about 2 months
after planting, mature potatoes for storing when the tops yellow and
back—about 4 months after planting, or after killed by fall frosts.
Gently lift from soil with a garden fork. Brush
soil off the tubers but don’t wash them until ready to eat. Store
at high humidity (75 to 90 percent) and
cool (40 to 50 degrees).
in a root cellar or similar location at 40 degrees or below (but
above freezing). Mine, stored in very slightly moist compost,
last well for 6 months or more. Some
varieties stored just above freezing may become sweeter. Leaving
them out at room temperature for a few
days may help if they are too sweet to taste.
Before cooking, cut off any green or damaged areas.