University of Vermont Extension
Department of Plant and Soil Science
Summer News
Article
FALL VEGETABLE
GARDENING
Dr.
Leonard Perry, Extension Professor
University of Vermont
Having a fall vegetable garden is
fun, easier than gardening at other times of the year, and extends
your season
for fresh produce. Many claim the same
vegetables grown in the fall are tastier and "sweeter" than those
earlier in the season. Late summer is
the time to start crops that mature quickly and take cooler
weather.
Growing vegetables in fall you can
take advantage of cooler weather outdoors, and avoid most weeds and
insects
that have come and gone. Generally fall
brings more rain, and with less heat, you'll have less watering.
Some crops prefer and grow best in cooler
weather, such as lettuce and traditional "cool season" crops as
carrots, beets, cabbage and kale.
To decide what to grow, there are a
couple considerations. Look at the days
to maturity listed on seed packets to see if your crops will have
enough time
to mature before frost. Keep in mind
some crops can be picked young, as with frequent picking of lettuce
leaves, or
young beets, carrots and turnips. Radishes are a root crop best
picked when
mature. Avoid crops such as bush snap beans that, although they
mature quickly,
require warmth and are killed by frosts and cold.
Crops also will vary in how much
frost and cold they will withstand.
Often we will get a light frost, followed by a warm period of
"Indian Summer" prior to harder frosts and colder temperatures.
Just a little protection such as from thin
fabric "floating row covers" may be all that is needed to get your
crops past the first light frosts. Many
other home frost remedies can be seen in fall gardens prior to cold
nights
including corrugated fiberglass panels, old towels or blankets
and sheets (held above plants on some form of boards or support),
and milk jugs
with bottoms cut out over individual plants.
Some use plastic water-holding walls around plants.
Vegetables that withstand light
frosts (and their days to maturity) include broccoli (50-70 days),
carrots
(50-60 days), cauliflower (60-80 days), cilantro (60 to 70 days),
kohlrabi (60
to 70 days), leaf lettuce (40 to 60 days), mustard greens (30 to 40
days),
spinach (35 to 45 days), Swiss chard (40 to 60 days), and turnips
(50-60
days). From the day you want to plant,
count out this number of days to see if your crops will mature
before the usual
first hard frost for your area. Keep in
mind that cultivars differ in their days to maturity, so look for
ones with the
fewest days.
Hardier vegetables, surviving
temperatures into the high 20s (F) include beets (50 to 60 days),
(green onions
(60 to 70 days), peas (70 to 80 days, longer than in the spring),
radish (25-35
days), and turnips (50 to 60 days).
Hardiest vegetables, surviving temperatures to the low 20s, include
Brussels sprouts (90 to 100 days), collard greens and kale (both 40
to 65
days). Plant garlic after the first
frost but two to four weeks before the first heavy frost, and
shallots after
the first frost, for harvest the following summer. These are
planted late to avoid stimulating
top growth only to be killed by cold.
Fall gardens can be planted in new
beds, or ones vacant after the harvest of many of the same crops
grown in
spring. Just make sure to rotate crops
for best growth and to minimize diseases and pests. Don’t plant a
crop in the same part of the
garden where it was grown in the last couple years.
If replacing spent or dead crops,
make sure to remove all plant residue and roots, adding a fresh
supply of
compost or rotted (weed-free) manure and other fertilizer as called
for by a
soil test. If you have fertilized well
through the season, no additional fertilizer may be needed. Or, if
plants appear to be growing slow and
are yellowish, you may water with a liquid fertilizer for
vegetables,
or apply a light application of a general purpose dry fertilizer
along the
rows.
If sowing seeds in hot weather, a
couple methods can be used to provide the cool soil that fall
crops prefer to germinate and grow best.
You can lay some form of shade such as snow fencing or lattice
supported
on boards, or a shade cloth fabric over the bed while seeds
germinate and
plants become established. It’s best not
to use a frost blanket as you would use later in fall, as this will
keep
seedlings too warm.
Or you can water the beds to cool
the soil, cover with a few inches of straw, then water again.
Remove the straw in a few days and sow in the
now cooler soil. Replace the straw as mulch once plants are growing.
Simply
using a thick layer (6 inches or so) of straw on some root crops as
carrots can
keep the soil from freezing and extend their harvest into early
winter. As with vegetables sown at other times, make
sure to keep them watered if rains don't.
To extend your growing season even
more, consider growing in coldframes.
These can be as complex as commercially made dual-wall solid
polycarbonate panel units, with automatic venting. If these have
some additional heat, as from a
heating cable, they are called "hotbeds". Perhaps most simple is a
row of straw bales around plants supporting an old window sash or
wood frame
with corrugated fiberglass panel. If not
automatically vented, make sure to vent on hot days so plants don't
get
overheated. Since covered and not
exposed to rain, make sure to check often for watering. Using
coldframes you can have vegetables well
into winter, even after snow falls.
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