Irrigation:
Water management is critical to the development of vigorous vines and the maintenance of the foliage canopy, which supports fruit growth and protects developing fruit from sunburn. Pumpkins can be grown using sprinkler irrigation, but drip and furrow irrigation are also used. Trickle irrigation is best, but "soaker hoses" also work well. Overhead sprinklers are effective; however, wet foliage increases the chance of disease, especially mildew.
Frequent irrigation aggravates root and stem rotting problems and increases the humidity in the lower canopy, which contributes to foliage and fruit diseases. Irrigation management should emphasize infrequent, deep watering to encourage deep root development and allow time for the soil surface to dry between watering. When overhead irrigation is used, water should be applied early in the day so leaves can dry before nightfall to reduce the incidence of fruit-rotting and foliar diseases. Water deficiency or stress, especially during the blossom-fruit set period, can reduce fruit size or cause blossoms and fruits to drop, resulting in reduced yields. Additionally, sandy soils require close attention to water management (more frequent irrigation) to avoid moisture stress and interruption in foliage or fruit growth.
The use of a potentiometer is a useful tool to determine moisture levels in the soil. In the absence of such equipment, a simple way to determine the moisture level of the soil is to take a handful of soil and squeeze it. If the soil sample holds together and is sticky, the level of moisture is adequate; if the sample crumbles them moisture levels are inadequate and the filed must be irrigated.
Pumpkins require a good supply of water to produce large thick walled fruits. The source of water supply (ponds, drains, rivers etc.) used for irrigation can be a potential source of biological and chemical hazards.
A recognized laboratory for microbial, chemical and mineral pollutants should analyze water used for irrigation at least once per year. Proper record keeping of microbial, chemical and mineral pollutants of the water is an important Good Agricultural Practice (GAP). Also, water storage tanks should be kept covered to ensure that they do not become contaminated with bird faeces.
