by Glenn Davis, UCCE Master Gardener, El Dorado County
February 2002
Potatoes, discovered in South America, taken to Europe,
cultivated there and on to North America to become one of our favorite foods. Some say if you had only one vegetable to
survive on, the best would be the potato.
Potatoes are produced on underground stems so they need a lot
of room in the garden. They also do
best in an acidic soil that drains well and has a lot of compost or well-cured
manure mixed in. Potatoes like the sun
but the tubers themselves should not be exposed; if they are the potato will
turn green and become toxic.
Potatoes can be started a couple of weeks before the last
frost, usually as early as the ground can be worked. They can be damaged by frost, so be a little careful about trying
to get them in too early; our last frost date is usually about the middle of
April, higher elevations are later (about a week per thousand feet). There are a lot of varieties; most range
from white to yellow with a few exotic others thrown in. Almost any nursery or garden catalog will
have them available. Make sure they are
certified “disease free” and are “seed” potatoes when you make your
purchase. About two pounds of seed
potatoes will produce 50 pounds of potatoes.
Potatoes purchased in the grocery store are usually treated to prevent
sprouting.
After you purchase your potatoes, divide them into parts about
1 l/2 inches wide with at least two sprouts on each piece. Put them in a cool dry area and give them a
day or so to form a covering over the cut portion. They can be planted in rows, hills, beds or containers. It takes a potato about three months to
reach maturity, however, there are some varieties than can be harvested
earlier. If you plant them in rows, the
spacing between the rows should be about 3 feet and between each plant about 12
inches.
The suggested planting depth is about 4 inches; the usual
process is a trench about 6-8 inches wide and about a foot deep with the
potatoes in the bottom and covered with about 4 inches of soil. If you have a really heavy soil it will help
to mix a lot of compost into the bottom of the trench before putting the potatoes
in. Usually the compost is enough
nutrition, but if you feel a boost is necessary a fertilizer such as 5-10-10
mixed into the bottom can be helpful.
High nitrogen fertilizers produce a lot of great greenery but do little
for the potatoes beneath ground; in fact high nitrogen fertilizer can result in
smaller potatoes at harvest time. If
you are growing your potatoes in a row, fertilize down the middle of the row.
As the potato plant emerges start filling in the trench until it has reached
the normal garden level or higher. Some
gardeners continue to mound compost or soil around the plant until it starts to
bloom; if you go this route make sure there is about 4 inches of potato plant
available above the mound to feed the growing potatoes below.
You can start your harvest when the blossoms fade and a full
harvest when the plant deteriorates.
Cut off the plant at ground level and leave the potatoes in the ground
for a week or so. Harvest by carefully
spading around the outside of the plant and tipping the potatoes up. Potatoes with a spade puncture cannot be
stored successfully, so use those first.
They should be stored in a dry, cool (about 40 degrees), sun-free
location.
Potatoes can be grown in plastic garbage cans, round wire
enclosures, stacked tires and just mounded earth. Start them, in the same manner mentioned above, about an inch or
so underground and as they grow add compost, hay, or leaves. The new potatoes will grow well in these
mediums, in fact pine needles, with their acidic nature, are an excellent
medium. If you are growing them in
tires, as each tire fills with your growing medium add another tire until the
plant starts to set flowers. To harvest
your potatoes simply turn over the container.
In addition to potatoes there are a lot of other great spring
vegetables out there; for information on these or on any garden problem contact
the El Dorado County Master Gardeners, 621-5512, Monday through Friday, 9:00 AM
to Noon.