Crop Guide – Cucurbits

PLEASE REMEMBER TO ALWAYS READ THE LABEL BEFORE USING ANY CHEMICAL

Cucurbits – this group of crops includes pumpkins, squashes, vegetable marrows, cucumbers, musk and sweet melons, and watermelons, as well as loofah, calabash and various gourds.

CLIMATE REQUIREMENTS

• The minimum soil temperature for good germination is approximately 18°C, and the maximum 30°C to 35°C. Seed germinates relatively poorly at temperatures below 15°C and such temperatures also retard root growth. All curcubits are sensitive to frost. Almost no growth takes place at temperatures below 15°C, but is rapid between 18°C and 30°C.
• Plants grow more luxuriantly at higher temperatures. However, relatively low temperatures and short daylight periods promote the formation of more female, in relation to male, flowers; while at high temperatures (35°C or more) only male flowers may be formed. There is poor pollination of female flowers when temperatures drop below 10°C for pumpkins and squashes, 15°C for watermelons and cucumbers and 20°C for muskmelons; higher temperatures tend to promote pollination.
• High atmospheric humidity, especially in the later growing stages, and particularly for muskmelons and watermelons, favour the development of fungal diseases. Prolonged cool, cloudy or moist weather over the flowering season will often reduce bee activity, and result in poor pollination of flowers and a reduced fruit-set.

SOILS

• Sandy loam to loam soils, with a clay content of 15% to 30% clay, which are well-drained to a depth of 900 mm, or more, are ideal. The minimum soil depth is 450 mm. The surface of heavier soil types tends to remain damp too long and may promote fruit rots.

PLANT SPACING AND SEEDING RATES/HA

• Pumpkins and Hubbards – 500 mm x 2.0 to 2.7 m (4 to 6 kg)
• Butternuts, Gems and Table Queen – 300 to 500 mm x 1.2 to 1.8 m (2 to 3 kg)
• Cucumbers – 300 mm x 1.2 to 1.5 m (2 to 3 kg)
• Melons – 300 mm x 1.5 to 2.0 m (3 to 4 kg)
• Watermelons – 500 mm x 1.8 to 2.5 m (3 to 4 kg)
• Bush types – 300 to 500 mm x 1.2 to 1.5 m (4 to 6 kg)

TIME OF PLANTING

• Cucurbits do not normally transplant easily, so are usually direct-seeded in the land. Often 2 to 4 seeds are planted on each site and excess plants later thinned out.
• Occasionally, use is made of young seedlings, especially for squashes and marrows, where early crops are wanted in cooler areas; seeding rate for this purpose varies from 1 to 3 kg per ha.
• Planting in cooler areas should be delayed until after the last frosts, and when the soil has warmed up to at least 18°C. The crop should be harvested before the first frosts of winter.

IRRIGATION

• The soil should be kept fairly moist until the crop has emerged.
• To encourage deep rooting the soil should, during the first third of the growing period, be wet to a depth of 450 mm, whenever 90% of the available soil moisture has been depleted. Thereafter, allow only 50% depletion before wetting the soil to a depth of 600 mm. Adequate watering from flowering onward is most important.

Fertilizer Program

This is a broad outline for the fertilization of curcubits. Recommendations will vary depending on specific soil samples.

Chemical Program

Weed Control

Pest Control

Disease Control