Cultivating cucurbits

Follow these useful tips on fertilising, irrigating, harvesting and storing your crop.

A selection of cucurbits grown in South Korea.
Photo: cropsforthefuture.org

Apply lime, fertiliser or manure according to the recommendations of a soil test. If necessary, apply lime four weeks before planting and work it in to a depth of 20cm.

Soil pH(H2O) must be between 5,5 and 7.

If recommendations are not available, apply about 1 000kg/ ha (100g/m²) of a fertiliser such as 2:3:4 (27) in a 40cm-wide strip, and work it lightly into the soil just before planting.

Use compost or manure at about four handfuls/ m² to partly supplement the chemical fertiliser.

Pumpkins and squashes need a good leaf canopy to prevent sunburn, so apply LAN as a top dressing three weeks after transplanting or emergence at 120kg/ha to 150kg/ha, or 10g/m row length, 10cm from the stems.

Follow this up with a second top dressing five weeks later if needed. Water well after each application.
Irrigate regularly to keep the soil moist during the growing season.

Cucurbits require uniform irrigation for optimal yield. Reduce irrigation as crops reach harvesting stage.
Bees are essential for cucurbit production. Wild bees and other insects are normally sufficient to pollinate small plantings.

At harvesting, carefully remove the mature fruit from the vines by cutting through the stalks. Damage to fruit can reduce storage life and promote disease.

Guidelines from planting to harvesting
Squash: 60-75 days
Butternut squash: 90-100 days
Muskmelon: 90-100 days;
winter muskmelon: 105-125 days
Watermelon: 95-120 days
Pumpkin: 120-150 days
Yield estimate for pumpkins and melons: 300kg/m²; for squash: 200 kg/m².

Storage
After harvesting, pumpkins/squashes should be cured to keep them longer in storage.

Curing hardens the shell, heals superficial wounds, reduces the high water content of the fruit, and improves eating quality.

Cure the fruits by keeping them indoors at room temperature for a week or two.

Cucurbits require mild, fairly dry storage conditions.

After curing, carefully place the fruit in a single layer on shelves, leaving a small space between them.

Source: Production Guideline for Summer Vegetables, ARC.