Cucurbits include cucumber, pumpkin, zucchini, squash, watermelon and rockmelon. These all share traits and enjoy similar growing conditions.
All are easy to grow and highly productive in the home garden. Pumpkin and watermelon vines require room to grow but can trained over structures. Cucumbers and rockmelons require less space and can be grown vertically on a trellis or obelisk.
Climate
• Cucurbits require warm, frost-free conditions.
• In cool areas, seedlings can be started in protected positions and planted out once the risk of frost has passed.
• Spring and autumn are best for zucchini and cucumber in the subtropics, but watermelons and pumpkins will continue to thrive throughout the summer.
• Cucurbits can grow for most of the year in the tropics, but perform best in the dry season (April – September).
Position
• All cucurbits prefer full sun
• Their foliage (particularly zucchini and squash) is easily damaged and dried out in hot winds so grow in a protected position.
Planting
• Cucurbits require warm, frost-free conditions.
• In temperate and subtropical areas, sow seeds or plant cucurbits seedlings from September to January. In cool areas, seedling can be started in protected positions and planted out once the risk of frost has passed.
• Seeds and seedlings are readily available at Burbank House & Garden during the planting season.
• If planting seeds, plant 2-3 seeds in each planting mound 10cm apart, and then thin them out to leave only the strongest seedling.
• Water seeds in well, but don’t water them again until they germinate – they are very prone to rotting.
• Don’t overcrowd cucurbits. They are very prone to fungal disease and need good airflow around the vines. In general, allow 2m between pumpkin and watermelon vines, 1m between zucchinis and squash and 20-30cm between cucumbers.
Watering and fertilising
• Cucurbits are vigorous growers. Apply an all-purpose organic fertiliser in the first week after planting. Follow up with regular light applications every 3-4 weeks.
• They have lots of foliage and dry out easily. Keep soil at the base of plants evenly moist as irregular watering can lead to poor production and poor-quality fruit.
• Avoid watering the foliage and fruit where possible to reduce fungal problems.
Support
• All cucurbit vines will climb if you let them.
• It is best to grow cucumbers on a 1 to 2m high trellis or support. This will support the vines and fruit, save space and keep the fruit off the ground.
• Pumpkins and melons can be trained over fences or structures to save space in small spaces.
Overcoming poor fruit set
Poor fruit set in cucurbits is often due to inadequate pollination and lack of bees. Pollinating flowers by hand is easy to do and will ensure an abundant crop. Identify the male and female flowers. Males have long slender stems and female flowers have a swollen base. Pick off a male flower, remove the petals to reveal the central ‘style’. Use a small artist paintbrush to brush the pollen onto the pistil inside the female flower. This is best done early in the morning.
Harvesting
Use secateurs to remove the fruits from their vines to avoid damage to fruit and vines. Leaving a length of stem on the harvested fruit helps to minimise deterioration.
Pumpkin – Harvest when stems are hard and dry. Clean and dry fruit and store in a cool, airy and dry spot.
Watermelon – Picking a ripe watermelon from the garden is one of life’s greatest pleasures. Give the fruit a tap – a ripe melon will have a dull thud sound. Also check the skin of the fruit where it meets the ground. It should be a yellow-white colour when mature.
Rockmelon – Smell the fruit. Ripe rockmelons have a strong sweet smell and come away freely from the vine. Store in the fridge.
Zucchini and Squash – Harvest young (zucchini 15-20cm long, squash 7-15cm wide) and store excess in the fridge. Larger fruit looks impressive but become watery and lose flavour. Check and harvest plants every 1-2 days.
Cucumber – Depends on the variety and use. Small fruit less than 10cm long are best for picking. Harvest young to avoid large seeds.