There is always a market for pumpkins and the right varieties have a good storage life. A versatile and nutritious vegetable, pumpkins contain potassium and beta-carotene and the seeds are rich in zinc.
A warm season crop, the pumpkin likes full sun accompanied by an adequate water supply because of its shallow rooting system. It is temperature sensitive and seed takes longer to germinate when temperatures are low. But at 25°C pumpkin seed can germinate in 2 days.
Horticulturalists advise a planting depth of between 3 cm and 5 cm; a planting space of 0.5 m to 1 m (between plants) and an inter-row distance of between 2.5 m. Leaving aisles between the rows makes it easier to spray and weed.
Pumpkins like slightly acidic, well drained, sandy loam soils. Soil that is more acid than pH 5.5 may need correction with agricultural lime.
Disease comes in with high temperatures and frequent rain. Prevention is better than cure, so the first call is to buy resistant, disease-free seed, every season. Observation, checking and daily field scouting, is the farmer’s own early warning system and a sharp pair of eyes can save a crop.
Rotate the crop every two years, restrict movement of people in the field and remove crop debris which can harbour disease. Copper spray fungicides give reasonable control against pathogens and work well in slightly acid environments.
Powdery mildew, downy mildew and blight (Phytophthera) are important diseases in pumpkins because of the field production losses they cause. Chemical control is required for these pathogens.
Aphids act as virus vectors and cause direct damage to plants, although plants can tolerate medium to low level infestation of aphid. Heavy aphid loads need chemical pesticide control.
Pumpkins also fall prey to the deadly armyworm. British scientist, Prof. Kenneth Wilson works with the Zambian government, and Paul Desmairais of the Kasisi Agricultural Training Centre, co-ordinating a project for biological control of armyworm through a virus.
Plant up to October, November into a fine seed bed that has been loosened (by tractor or by hand) to a depth of 30 cm to 40 cm with all the clods broken up. The manure, compost or fertiliser should be well worked into the soil, and seeds planted, in pairs, at a depth of 3 cm to 4 cm. When the seedlings are thriving, the extra plants can be thinned out.
The planting area should be properly irrigated before planting and then not irrigated until after emergence. Water the base of the plant so as not to splash the leaves and keep the weeds down.
Pumpkins are best harvested with a sharp knife leaving some stem length attached to the pumpkin which allows it to keep better.