University of Vermont Extension
Department of Plant and Soil Science
Spring (late), Summer News
Article
GROWING SQUASH
Dr.
Leonard Perry, Extension Professor
University of Vermont
Each
year the National Garden Bureau picks a vegetable to feature, with the
Vegetable of the Year for 2010 being the squash. There are many
varieties of this easy-to-grow
native vegetable, in various shapes and colors.
Evidence has been found in caves in Mexico and the
Southwest that squash existed at least by 5000 B.C., and was being
grown by
native peoples about 4000 B.C. Grown
together with two other native crops-- corn and beans-- it was one of
the
"three sisters". The corn
provided support for the beans, and the squash provided a groundcover
for weed
control. These crops migrated with
humans to eastern North America, where they
were discovered and introduced to Europe by
early settlers and explorers in the late 16th century.
Squash
is one of the many members of the cucurbit family, along with other
common
vegetables such as cucumbers, melons, and gourds. They are
generally divided into two groups,
the summer and winter squash, depending on when they are
harvested. You'll see further groupings or types in
catalogs, often based on fruit shape. The
summer squash include either crookneck or straightneck, scallop or
patty pan,
zucchini, and vegetable marrow. The
winter squash include acorn, banana, buttercup, butternut, delicata,
delicious,
and hubbard.
The
summer squash need warm weather for best growth. They are harvested in
summer,
before the fruits are fully mature in order to have the best flavor and
texture. Seeds should not be fully
developed, and the skin should be able to be scraped easily with the
fingernail. They can be harvested at most any immature stage,
even quite
small. These store only a few days in
the refrigerator but are easily frozen.
To
freeze zucchini, yellow crookneck, or other summer squash, wash after
harvest
and slice. Blanch in boiling water for 3
minutes to destroy enzymes and bacteria that break down the
fruit. Then cool rapidly in running cold water, or
ice water. Strain and bag, using plastic
reclosable freezer bags (sold just for this and heavier than other
bags) or a
vacuum sealer.
Winter
squash, on the other hand, are harvested mature in fall around the time
of the
first frost. Skins should resist
fingernail pressure. Although this group
needs warm weather for seeds to germinate and plants to grow, cool
nights are
needed for best flavor to develop in fruits.
They store well, such as in a cool room or basement, which stays around
50 to 55 degrees (F). Acorn squash can
store 3 to 4 months, other winter squashes can last up to 6 months with
proper
storage. If you are planning to store,
make sure to cut the fruit from the vines rather than twist or pull
them
off. Breaking the stem off the fruit
will leave an opening that rots can enter.
All
squash need full sun and a well-drained soil.
Squash can get large, so make sure you check the habit and spread
before
planting. Many summer squash have been
bred to be more compact, so need about 4 square feet per plant.
You can plant several seeds per small raised
hill, then thin later to 3 plants per hill.
Space hills about 4 feet apart, with any rows 5 feet apart.
Most
winter squash have a semi-bush habit or are vining. Allow more
space for these, about 12 square
feet per vining plant. For those winter
squash with small fruits, you can even train them onto a 4-foot high
trellis in
the back of the garden.
Many
sow the large seeds directly into the garden.
Since they need warmth to germinate
and grow, wait until the soil warms or else seedlings
will grow slowly and seeds may rot. If
the season is cool, or your garden is in the north with a shorter
growing
season, you may want to start
seedlings 2 or 3 weeks early indoors. Best is to sow into a peat
pot or similar
which can be planted directly into the garden (they don't like
transplanting). Keep seeds indoors in as
much
warmth and sun as possible, and don't allow to dry
out.
Since
squash are vigorous, they require more fertilizer than some other
crops. Work
plenty of compost into the soil prior to planting,
then fertilize once plants get a few inches tall. You can use a
granular or liquid fertilizer,
organic or synthetic. Fertilize again
after a month or 6 weeks.
Mulching
will help keep weeds down early on (the plants with their large leaves
do this
later) that can compete with plants for nutrients, and that foster
insects and
diseases. Examples of mulches are straw
(not weedy hay), newspapers with some organic material like shredded
leaves, or
plastic similarly covered.
Summer
squash will need plenty of water (water deeply and less often is
better)
through the season, especially during bloom and fruit
development. Winter squash can tolerate some drought once
they are established. Between you and
the rain, the soil should be wet to a depth of 10 inches or more each
week. Keeping water off leaves when
watering will help prevent powdery mildew disease.
Choosing
the right site, using mulches with spot hand weeding, and proper
culture will
go a long way to controlling insects and diseases. If plants
suddenly wilt, often starting one
stem at a time, chances are they have a bacterial wilt. It, and
viruses that stunt or deform plants,
are spread by insects. Control these and
your plants may remain free of disease.
The
three main insects to watch for are the striped cucumber beetle, the
squash
bug, and
the squash vine borer.
The adult beetle is yellow to black, striped to spotted, and about 1/4
inch long. It feeds on most plant parts.
Covering plants with fine netting will keep these away.
The
adult squash bug is flat, brownish-gray, and about 5/8 inch
long. It is
usually found on undersides of leaves where it sucks plant
juices. Put some boards in the garden where these
insects can hide under, and are then easily found and
removed.
The
borer does just this, the larvae or caterpillar stage makes tunnels in
stems. This causes them to wilt rapidly,
then die. You can make small cuts in
stems to carefully remove borers, cut off badly damaged stems, and
early in the
season lay foil in the garden to confuse the moths that lay the eggs
that hatch
the larvae.
Whether
you grow your own squash, buy it from local farmers, or get it from
friends (as
often happens with the prolific zucchini), consider putting some up for
winter. You'll benefit from the fresh
flavors well past the season, as well as the nutrition of these
vegetables. Zucchini is lower in
calories than many fruits and vegetables.
Although winter squash has the same calories roughly as potatoes, it
has
more than twice the potassium. Winter
and yellow squash both provide Vitamin A
and minerals that may reduce the risk of certain cancers.
More
details on these and other vegetables of the year can be found on the
National
Garden Bureau website
(www.ngb.org).
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Perry's Perennial
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