Vegetable Harvest and Storage
Denny Schrock
Department of Horticulture
Timely harvest and proper storage help to maintain the quality and freshness of garden vegetables. This publication gives information on how and when to harvest vegetables, special harvest preparations and storage requirements, and appropriate length and kinds of storage.
The following terms are used in this publication:
- Light freeze
28 to 32 degrees Fahrenheit
- Moderate freeze
24 to 28 degrees Fahrenheit
- Severe freeze
Less than 24 degrees Fahrenheit
You should recognize that "ideal" storage conditions for many vegetables are not attainable around the average home or farm. It is important, therefore, to recognize the limitations of the best storage available.
Refrigerators can be used for storage. If two refrigerators are available, one can be kept at a cold temperature (32 to 40 degrees) and the other at a cool temperature (45 to 50 degrees). If there is only one refrigerator with the control set for normal operation, the temperature in the center storage section is usually between 38 and 42 degrees Fahrenheit. Check the setting of the temperature control by placing a thermometer in different places in the refrigerator. Remember also that frequent opening of the refrigerator door raises the temperature inside.
Basements are also possible storage places. Temperatures in most heated (air-conditioned) basements will usually be 65 degrees Fahrenheit or warmer in summer and 60 degrees Fahrenheit or cooler in winter. Separate sections can be partitioned to vary the temperature and humidity. You can use outdoor air, dirt floors or wetted sacks to vary the temperature and humidity needs. Unheated basements, if well ventilated, can provide good storage conditions for some vegetables.
Different vegetables require different temperature and humidity levels for proper storage.
Cold, moist storage
32 to 40 degrees Fahrenheit 90 to 95 percent relative humidity
Root crops
- Beets
Begin harvest when beet is 1 inch in diameter or smaller for baby
beets. Main harvest is when beets are 2 to 3 inches. Tender tops make excellent
greens regardless of the size of the root ball. Harvest spring-planted beets
before hot weather (July). Harvest fall beets before the first moderate freeze.
For storage, wash roots, trim tops to 1/2 inch, place in perforated plastic
bags and store in refrigerator, cold moist cellar or pit. Storage life is 2
to 4 months.
- Carrots
Harvest spring carrots before hot weather (July). Baby carrots may
be harvested when roots are 3 inches long. Fall-planted carrots should be harvested
before the first moderate freeze. For storage, wash roots, trim tops to 1/2
inch, place in perforated plastic bags and store in refrigerator, cold moist
cellar or pit. Storage life is 2 to 4 months. With a heavy layer of mulch, carrots
may also be overwintered outdoors in the ground.
- Horseradish
Harvest after several severe freezes. Store in the ground all winter;
mulch with straw or leaves and dig when needed.
- Parsnips
Harvest in late fall after several moderate freezes. Exposure to cold
develops the sweet flavor. For storage requirements, see carrots.
- Potato, Irish
Harvest in July when the tops have yellowed or died. Do not leave in
ground exposed to high soil temperatures from sun. Wash potatoes and remove
the diseased or damaged ones. Cure for about a week in a shaded, well-ventilated
place (open barn, shed, garage). Avoid exposing tubers to light. Store in as
cool a place as possible at this time of year. You are not likely to find ideal
storage conditions (40 degrees Fahrenheit, 85 to 90 percent relative humidity) at this time
of year other than commercial cold storage. Cool basements are probably the
best storage available. Keep humidity high and provide good ventilation. Storage
time is 2 to 4 months.
- Radish
Harvest when 1/2 to 1 inch in diameter. Wash roots, trim both taproot
and tops and store in plastic bags in a refrigerator for up to a month. Winter
or black radishes are stored the same as carrots.
- Salsify
See parsnips for harvest and storage.
- Turnip
Turnips can be harvested from the time they are 1 inch in diameter.
They are best as a fall crop and can withstand several light freezes. Store
the same as carrots. Turnip greens may be harvested and used the same as beet
greens.
Cole crops (cabbage group)
- Broccoli
Harvest terminal head while florets are still tight and of good green color. Smaller side heads will develop. Store in perforated plastic bags for up to one week in the refrigerator. Freeze any surplus. Best quality will be found in shoots that are harvested during cool weather.
- Brussels sprouts
Harvest the sprouts (small heads) when they are firm; begin from the
bottom of the plant. Sprouts can stand several moderate freezes. Harvest all
sprouts prior to the first severe freeze and store in the refrigerator in perforated
bags for up to 3 weeks. Freeze any surplus.
- Cabbage
Harvest when heads are solid. Remove loose outer leaves. Store cabbage
in refrigerator, cold cellar or outdoor pit in plastic bags for up to 2 months.
- Cauliflower
Tie outer leaves above the head when curds are about 1 to 2 inches
in diameter (except colored types). Heads will be ready for harvest in about
2 weeks. Cauliflower may be stored in perforated plastic bags in the refrigerator
for up to 2 weeks. Freeze any surplus.
- Chinese cabbage
Grows best in the fall, although varieties that mature in less than
55 days can be planted in early spring. Harvest head after the first moderate
frost in the fall and store in perforated plastic bags in the refrigerator,
cold cellar or outdoor pit. Chinese cabbage will keep for up to 2 months. Harvest
spring cabbage when heads solidify but before a seed stalk forms.
- Kohlrabi
For standard types, harvest when the swollen stems are 2 to 3 inches
in diameter. Stems become woody if left too long before harvest or if grown
under poor conditions. Giant, heirloom types may reach 1 foot in diameter and
still retain high quality. Cut off root and leaf stems and store in plastic
bags as indicated for carrots. Storage life is 2 to 4 weeks.
Greens
- Chard (Swiss)
This is a summer green that is harvested continuously. Merely break off the outer leaves. Swiss chard is a beet relative developed for its top. A spring planting will provide greens from early summer to the first moderate freeze. Store in plastic bags up to 2 weeks in refrigerator.
- Collards, kale, mustard, spinach
Harvest the leaves and leaf stems of greens when they reach suitable
size. Either harvest the whole plant or the outer, larger leaves. Greens do
not store well, but may be kept in plastic bags in the refrigerator for up to
2 weeks. Freeze any surplus.
Salads
- Endive (Escarole)
Harvest whole plant. Wash thoroughly to remove soil and sand. Gather leaves together and tie with rubber band. Store in plastic bags in refrigerator for up to 3 weeks.
- Lettuce
Head, semi-head and leaf lettuce can be stored for up to 2 weeks in
perforated plastic bags in the refrigerator. Individual leaves may be harvested
at any stage of development before the plants bolt (go to seed). For best quality,
successive plantings at two-week intervals are suggested.
- Parsley
Parsley will overwinter if planted in a protected place such as a cold
frame. If planted in the open, it can be carefully lifted with a ball of soil
just before the soil freezes, potted and taken into the house in a cool, sunny
room and harvested for several weeks. Parsley leaves will keep in plastic bags
in the refrigerator for about one week.
Legumes
- Lima beans
Harvest when pods have filled. For tender limas, harvest when a bit
immature; for "meaty" limas, harvest when mature. Shelled limas can be stored
in perforated plastic bags in the refrigerator for about a week. Surplus limas
can be canned or frozen.
- Garden peas
Harvest when pods have filled. For tender peas, harvest when a bit
immature; for "meaty" peas, harvest when mature. Unshelled peas can be kept
in a perforated plastic bag in the refrigerator for about a week. Freeze or
can surplus. Oriental or snow pea types are harvested when pods are full-sized
but before the peas inside begin to swell. Edible podded or snap peas are harvested
when pods have filled out but before the peas inside become starchy.
- Southern peas (Crowder, Purple Hull, etc.)
For fresh use, freezing or canning, harvest when seeds are large and
plump but moist. Either shelled or unshelled peas may be stored in the refrigerator
for several days.
Other vegetables
- Asparagus
Harvest by snapping 6- to 12-inch spears off at ground level but before the top begins to fern out. Store in plastic bag in refrigerator for up to one week. Freeze or can any surplus.
- Onions, green
Harvest green onions when they attain sufficient size. Cut off roots;
remove top, leaving an inch of green. Place in plastic bag and store in refrigerator
for up to 2 weeks.
- Rhubarb
Harvest leaf stalks when 1/2 to 1 inch in diameter. Do not use leaves.
Rhubarb can be stored in perforated plastic bags for up to 3 weeks in the refrigerator.
Surplus rhubarb can be frozen.
- Sweet corn
Harvest sweet corn when kernels are plump and tender. Silks will be
dry and kernels filled. Check a few ears for maturity: Open top of ear and press
a few kernels with thumbnail. If milky juice exudes, it is ready for harvest.
Harvest at peak of quality, husk to conserve space, and store in plastic bags
for no more than two days in the refrigerator. The new super sweet varieties
will store for a week or more. Freeze or can surplus corn. Baby corn may be
harvested just as silks emerge, before the ear is 3 inches long.
Cool, moist storage
45 to 50 degrees Fahrenheit 80 to 90 percent relative humidity
Vine crops
- Cantaloupe (muskmelon)
Harvest when the stem slips easily from the fruit. Lift the melon; if ripe it should separate easily from the vine. Store ripe melons in the refrigerator in a plastic bag for up to 10 days. Try a few boxes of frozen melon balls.
- Squash, summer
Harvest when fruit is young and tender. Skin should be easily penetrated
with the thumbnail. Store for up to a week in a perforated plastic bag in the
refrigerator.
- Cucumber
Harvest cucumbers before seeds become half-size. This will vary with
variety. Most varieties will be 1-1/2 to 2-1/2 inches in diameter and 5 to 8 inches
long. Pickling cucumbers will be a bit more blocky and not as long as slicers.
Store slicing cucumbers in the warmest part of the refrigerator (45 to 50 degrees).
Place in plastic bag. Storage life is about one week. Pickling cucumbers should
be cooled quickly in ice water and can be kept up to two days in a plastic bag
in the refrigerator.
- Watermelon
Harvest when underside of fruit turns from whitish to yellowish. The
tendril at the juncture of the fruit stem and the vine usually dies when the
fruit is mature. Thumping an immature melon gives a ringing metallic sound,
while a mature melon gives a dull thud. Watermelons will store at room temperature
for about a week and at a temperature of 45 to 50 degrees Fahrenheit for 2 or 3 weeks.
Other vegetables
- Eggplant
Harvest when fruits are nearly full-grown, but color is still bright. Eggplants are not adapted to long storage. Keep in warmest part of refrigerator (45 to 50 degrees) for about a week.
- Beans, green
Bean pods will be most tender when the small seed inside is one-fourth
normal size. The pods become more fibrous as the beans mature. Harvest before
pods begin to swell because of the developing bean seeds inside. Store green
beans up to one week in perforated plastic bags in the warmest part of the refrigerator.
Can or freeze surplus.
- Okra
Harvest okra pods when they are 2 to 3 inches long. Over-mature pods
are woody. Store in plastic bags in the warmest part of the refrigerator for
about one week. Freeze surplus.
- Peppers, sweet
Harvest when fruits are firm and full size. If red, yellow or other
colored fruits are desired, leave on plant until mature color develops. Mature
peppers will be sweeter than green peppers. Sweet peppers can be stored for
2 to 3 weeks in the warmest part of the refrigerator in plastic bags.
Cool, dry storage
32 to 55 degrees Fahrenheit 50 to 60 percent relative humidity
- Onions, dry
Harvest onions when the tops have fallen over and the necks have shriveled. Remove tops, place in shallow boxes or mesh bags and cure in open garage or barn for 3 to 4 weeks. Store in mesh bags in as cool a place as can be found in midsummer (32 to 35 degrees). During humid (muggy) weather, keep ventilated.
- Peppers, hot
Pull plants late in the season and hang to dry in sun or a warm place.
Store in a dry cool place (usually a basement).
Warm, dry storage
55 to 60 degrees Fahrenheit 60 to 70 percent relative humidity
- Pumpkins, winter squash
Harvest pumpkins and winter squash when the skin is hard and the colors darken. Both should be harvested before frost. Remove the fruit from the vine with a portion of the stem attached. Store on shelves in a single layer so air can circulate around them.
Warm, moist storage
55 to 60 degrees Fahrenheit 80 to 85 percent relative humidity
- Sweet potatoes
Harvest in fall before frosts and freezing temperature. Handle carefully in the digging process. Cure for one week at temperature of 80 to 85 degrees Fahrenheit. Ideal storage is at 55 degrees Fahrenheit and 85 percent relative humidity. (This might be accomplished in a basement with ventilated boxes covered with periodically moistened burlap sacks.)
- Tomato
Ripe tomatoes will keep for a week at 55 to 60 degrees Fahrenheit. Green, mature tomatoes, harvested before frost, should be kept at a temperature
between 55 and 70 degrees Fahrenheit. For faster ripening, raise temperature to 65 to
70 degrees Fahrenheit. Mature green tomatoes should approach normal size and have a
whitish green skin color. Keep mature green tomatoes from 3 to 5 weeks by wrapping
each tomato in newspaper and inspecting for ripeness each week. Do not store
tomatoes in the refrigerator.
G6226, reviewed May 1998