Pumpkins

Vegetable Fact Sheets
Vegetable
Family Curcurbitaceae

Pumpkin
Cucurbita maxima.

Pumpkins can be confused with squashes, such as zucchini and button squash. The Butternut pumpkin is actually a gramma (Cucurbita moschata), a group of Cucurbits that includes the often curvy trombone squashes (The vegetable not the instrument), and these are climbing vines and look similar to zucchini. They can be planted out after the last frost. As the stems and leaves have very high water content, frost will kill the plants overnight. They originate from Central and South America. The Aztecs used to grow Corn, Beans and Pumpkin together and recent studies have found that eating these three foods together, they act as a protein. Unknown in Europe until the time of Columbus, pumpkins were first introduced to early American settlers by native Indian tribes, and were almost certainly part of the first American Thanksgiving. They are identified from other cucurbits by their more rounded form and less prickly foliage. They are grown for their hard skinned long keeping fruits, (up to eight months) but the shoots, tendrils, flowers and seed are also edible.

When to Plant

Aug - Jan. The seed will not germinate below 16oC and will rot in cold wet conditions. Germination occurs in 7-10 days. The pumpkin seeds can be soaked for 1-2 hours in warm water before planting, this will help with germination. Adding a couple of drops of liquid seaweed will also help with germination. The seed should be sown sideways or tip down, half in the soil. The seeds can rot off if over watered, so make sure the soil remains moist rather than soaking. Some people like to provide bottom heat to help the seed germinate. This would be more useful in a colder climate to extend the growing season of the pumpkin, as some need 150 days to reach maturity.

Soil Preparation

The soil should be prepared the winter before sowing by adding lots of half rotted compost, pumpkins do not like over rich soil. They do well in No-Dig Gardens. One method is to mound up your soil into little hills, make a well in the top and plant your pumpkins into the well. Or create small round no-dig beds in a bare or weed infested section of your garden and the vigorous vine will smother the weeds. There is a theory that pumpkins will out compete blackberries.

Spacing and Depth

Plant your seedlings or seeds, in groups of 2-3 spaced at 1.5-2m intervals, unless they are the clumping sort such as the variety Golden Nugget, that only has a spread of 1m.


Care

Home gardeners and others frequently become confused because many of the blossoms do not set fruit. They need to understand that the male and female parts are in separate flowers and only the female flowers produce fruits. Plants bear male and female flowers on one vine. In poor soil a pumpkins can be fed liquid seaweed or compost tea once a week. Pinching out growing tips promotes branching and increases fruit set. Pumpkins are pollinated by insects but can be hand pollinated to ensure purity, select female flowers and brush them with the male flowers, then cover them with pantyhose or a paper bag to stop cross fertilisation. Once the fruit is set it can be uncovered, labelled and left to mature. Putting straw underneath the developing fruit can prevent rot.

Harvesting
High-quality winter squashes and pumpkins are associated with maturity, so they should not be harvested until they are fully ripe. Fruits subjected to a hard frost will not keep, so harvest should be completed before cold weather. Clip the pumpkin from the vine keeping at least 5cm of the stalk intact.
Storage

Store only those fruit that are free of cuts, wounds, and insect or disease damage. Immediately after harvest, the fruit should undergo a ripening or curing process to harden the shell. Curing involves leaving the pumpkin in the sun and allowing it to dry completely. A curing period of about two weeks at 75 to 85 degrees F with good circulation is desirable. Storage should then be at 50 to 70 degrees F with humidity between 50 and 70 percent.

Common Problems

Flowers that form, then fade and fall off indicate poor pollination. Too much heat or rainfall can cause this. In this case hand pollination is nesssacary. Mildew diseases can attack the foliage, but if the plant is fast growing, leaves will be replaced. When the plants are becoming defoliated, improved air circulation and adding potassium is useful. Wetable sulphur can help solve mildew.

Varieties

Tonda padana-from NW of Italy, attractive winter squash, keeps well, good for soup, gnocchi or roasting

Matina di Chioggia-winter squash from near Venice, 2 kg fruit with sweet flesh, a good keeper

Jap- Excellent firm bright yellow flesh, then grey green shell, known in USA from 1860's, popular in Australia's hotter climates. 110 days to harvest

Jack-be-little -Tiny 5-7cm, sweet orange flesh, deeply ribbed flattened orange fruit, delightful miniature, appealing table decoration and craft, shelf life to 12 months, dried on the vine. 85-110 days to harvest