By Maurice Ogutu
University of Illinois Extension
Halloween pumpkins are harvested in September through October. Sometimes
harvesting may start in mid-August to early September, which requires
good handling and storage of the pumpkin fruit before selling to the
customers in late October. The first frost occurs in early to mid
October in northern parts of the state when the pumpkin fruits are
still curing outside in the fields. The growers in pick-your-own pumpkin
operations use this method to ensure that pumpkins are well cured
in the field before picked up by their customers. Some growers practicing
conventional pumpkin marketing systems where the fruit is picked,
washed, dried and sold to customers on weight or per fruit basis also
use this method. It is important to note that pumpkin fruits can tolerate
light frost that kill the vines only but more fruit loss can occur
if the frost caused injury on the fruit surface as the damaged areas
act as avenues for fungal and bacterial fruit rot pathogens. Remove
pumpkins from the fields before the hard freeze (when the night temperatures
are less than 27° F) or 80 percent to 90 percent of the fruits
may be at risk.
The pumpkin fruit is harvested when it is uniformly orange and the
rind is hard. Green immature fruits may ripen during the curing process
but not after the vines are killed by frost. The vines need to be
dry when fruits are mature. Handle the fruit with care to avoid cuts
and bruises. Harvest the fruit by cutting off the vine with a sharp
knife or a pair of looping shears leaving three to six inches of the
stem attached to the fruit. This makes the fruit looks more attractive,
and less likely to be attacked by fruit rot pathogens at the point
of stem attachment. Do not carry the pumpkin fruit using the fruit
stems because the fruit is very heavy and may lead to detachment of
the fruit stem. Wash the fruit with soapy water containing one part
of chlorine bleach to 10 parts of water to remove the soil and kill
the pathogens on the surface of the fruit. Make sure the fruits are
well dried before setting in a shed to cure.
Pumpkin fruits are cured at 80° to 85° F and 80 percent to
85 percent relative humidity for 10 days. This is done to prolong
the post harvest life of the pumpkin fruit because during this process
the fruit skin hardens, wounds heal and immature fruit ripens. After
curing, the fruits can be sold to the customers and the remaining
fruits stored.
Store the fruits in a cool, dry place. Put the fruits on a single
layer on wooden pallets with enough space in between the fruits (the
fruits should not touch each other), and do not place them on a concrete
floor. Improve the air circulation within the storage area by letting
in cool air at night and use fan to circulate air during daytime.
Do not let in warm air from outside into the storage during the daytime.
The optimal storage condition is 50° to 55° F temperature
and relative humidity of 50 percent to 70 percent. The relative humidity
is very important within the 50 percent to 70 percent range because
very high humidity leads to settling of moisture on fruit surfaces,
which increases decay of the fruit and low relative humidity may cause
dehydration of the fruit. Under these conditions you can keep the
fruits for about two to three months. Store the fruits away from apples
since apples produce ethylene gas as they ripen which speeds up the
ripening process in pumpkins, hence decreased shelf life. Check the
fruits regularly and remove the ones, which are rotten because if
not removed, will spread the pathogens in the storage area.
Winter squash
Winter squash such as Butternut, Acorn, Hubbard and other types are
mature when the skin (rind) is hard and cannot be punctured by thumbnails.
The mature fruit has a dull and dry skin compared to shiny, smooth
skin of immature fruits. Remove stem completely from Hubbard types
and if desired leave only 1-inch long stump on the fruit. Stems longer
than 1 inch tend to puncture adjacent fruits when in transit or storage.
Butternut, Hubbard and other squash types do not need be cured as
the benefits are less compared to pumpkins, while curing is very detrimental
in Acorn types as it leads to decline in quality. Acorn types have
the shortest storage time of five to eight weeks at 50° F and
relative humidity of 50 percent to 75 percent. Butternut, Turban and
Buttercup types can be stored at the same temperature and relative
humidity as Acorn types but have a longer storage time of two to three
months. The Hubbard types can be stored much longer than the rest
(five to six months) at 50° to 55° F and relative humidity
of 70 percent to 75 percent. Winter squash should be marketed or used
immediately when taken out of storage to avoid development of fruit
rot diseases.
Gourds
Gourds are of different flower colors (yellow, white), shapes and
sizes. They should be harvested before frost when fruit is mature.
As gourds mature, stems turn brown and become dry. Don’t use
the “thumbnail” test on gourds as it can cause dent on
the shell of unripe gourd and lower its quality. Harvest the fruit
by using a sharp knife or shears to cut the stem from vine and leaving
a few inches of the stem attached to fruit. Do not handle gourd by
stem since the stem can easily detach from the fruit and lower it’s
decorative value. If the fruit is dirty, wash in soapy water to remove
soil and rinse in clean water with household bleach one part to 10
parts water to kill soil-borne pathogens and dry each fruit with a
soft cloth. Spread the fruits so that they do not touch each other
in shelves lined with newspapers in a well-aerated shed. Turn the
gourds daily and change damp newspapers for one week. The outer skin
will harden this time and surface color develops. The gourds need
to be wiped with damp cloth soaked in household disinfectant and placed
in a warm, dry dark area for three to four weeks for further curing.
The decorative gourd can stay in its natural state for three to four
months and as long as six months with a protective coat of paint or
wax on the surface.
Ogutu is an Extension educator of horticulture at the University
of Illinois.
