Harvesting
Fruit mature five to six weeks after pollination. Poor fruit set may be due to poor pollination, disease, low temperatures, dry or wet conditions, low potassium, high nitrogen levels or too many established fruits.
Pumpkins mature about 14 to 22 weeks after planting, with the shortest time for butternuts and the small-fruited types, and the longest time for the large-fruited pumpkins.
An indication of maturity is cracking and corking on the stalks. The skin of the fruit changes to a dull colour, the flesh is deep yellow to orange and fingernails cannot penetrate the rind of the fruit.
Early crops of butternut and Japanese pumpkins may be harvested two to three times by selecting the most forward fruit, which is fully coloured with no trace of green on the skin. This may be sent straight to market. For most crops and for storage, the crop is allowed to mature on the vine and harvested when the vine has completely died off.
Storage enables marketing when prices rise to an economic level. The stems must be cut so they are 20 to 30mm long. Jarrahdale types will store for four to six months in winter/spring. Butternuts store for less than four months. Usually, they are stored at ambient temperatures.
The pumpkins must be mature and placed unwashed in a dry, ventilated and shaded area. If loose, they should preferably be placed on a slatted floor and stacked less than 1.0m high or less than four to five deep. They are often stored in shade in bulk bins and sometimes loose under trees. Remove rotten fruit regularly. They may also be kept in a coolroom at 10 to 13°C and 70 to 90% relative humidity.
Pumpkins yield from 12 to 40t/ha. Jarrahdale is usually the highest yielding, followed by Japanese, butternuts and bush pumpkins. About two to four fruits are obtained from each plant.
Marketing
Jarrahdale and Japanese pumpkins can be sold in half tonne or one tonne plastic bins or collapsible cardboard containers. Butternuts are mainly sold in 36L plastic containers or cartons. Small-fruited pumpkins are mainly sold in 22L containers.
Large pumpkins are usually cut into pieces and wrapped in clear plastic for retail sale. Butternuts are sold entire or are cut into halves.
Pumpkins may also be marketed as skinned, diced pieces wrapped in clear plastic for ready use.
Seed production from open-pollinated varieties
Seed may be saved from open-pollinated crops of butternuts and Jarrahdale pumpkins. Do not save seed from areas of mixed pumpkin varieties or from hybrid varieties, as it will not grow true to type. Crops must be more than 500m away from other pumpkin varieties, zucchini or squash if harvested for seed.
Giant pumpkin competitions
Competitions to find the heaviest ‘novelty’ pumpkins are held annually in every state. These are conducted in Western Australia in April. Special varieties such as Atlantic Giant are used, but are of poor eating quality.
The Australian record was established for a pumpkin weighing 300kg grown at Port Lincoln, South Australia in 2002. The record in Western Australia is 231kg for a pumpkin grown in Albany in 2000.
Acknowledgement
The original version of this material was authored by John Burt.