How to grow Pumpkin in New Zealand

Where to plant

Choose a sunny spot with room for the vines to run: a single plant can sprawl several metres. Pumpkins love rich soil, so dig in compost and sheep pellets, or grow them on the edge of a compost heap. Vines can also be trained up a strong fence or trellis to save space.

Rotate them with other crops and avoid planting where pumpkins, squash, zucchini or melons grew last season.

• Northland, Auckland, Waikato and the Bay of Plenty: sow or plant from October.
• Central North Island: sow in November so the fruit ripens before the mid-April frosts.
• Wellington, Nelson and Canterbury: sow or plant in November and December, once the soil is warm.
• Otago, Southland and Central Otago: wait until December, choose quick, smaller varieties, and start seed indoors in spring to gain time.

Choosing a variety

• Crown pumpkins such as Grey Crown have grey skin and dense, sweet orange flesh, and store especially well. Whangaparoa Crown is an old New Zealand heirloom.
• Buttercup is a compact, dark green squash-type pumpkin with dry, sweet flesh, popular in New Zealand kitchens.
• Butternut is pear shaped, with smooth, sweet flesh and few seeds, and stores well.
• Queensland Blue is a large, ribbed, blue-grey heirloom.
• Kumi Kumi is a traditional Māori squash, eaten young like a marrow or left to mature.
• Small varieties such as Golden Nugget suit small gardens and containers.

How to plant

1. For an early start, sow seed indoors in spring in pots, two or three weeks before you plan to plant out.
2. Outdoors, make low mounds of rich soil about 1 m apart once the soil is warm and frosts are over.
3. Sow three or four seeds in each mound and water well. Thin to the two strongest seedlings.
4. When planting seedlings, water them before and after planting, and handle the roots gently.
5. Mulch with pea straw to hold moisture and keep the fruit off damp soil.

Watering and feeding

Keep plants well watered while they establish and whenever the soil is dry, especially in hot or windy weather. Water at the base and avoid wetting the leaves, which encourages powdery mildew.

Feed every four weeks through spring and summer with a vegetable fertiliser, or weekly with a liquid feed.

Pruning and care through the year

• Pinch out the tip of the main stem once growth starts, to encourage side shoots that carry more fruit. Later, pinch the ends of rambling stems to keep the vine in bounds.
• For bigger pumpkins, let only two or three fruit develop on each plant.
• Pumpkins have separate male and female flowers and rely on bees. If fruit is not setting, hand pollinate early in the morning by brushing the centre of a male flower onto a female flower, the one with a tiny swollen fruit behind it.
• Sit developing fruit on a board or straw to keep it off wet soil.

Harvesting

Harvest once the vine is dying back, the stalk has turned brown, dry and corky, and the skin is hard enough that a fingernail does not mark it. Cut the fruit with a length of stalk attached, and pick before the first autumn frost.

To store, cure the pumpkins in the sun for about a week, then keep them in a cool, dry, airy place off the ground. With unbroken skin and stalk, they keep for many months, often ten or more.

Growing in pots

Choose a small variety such as Golden Nugget and a large container of vegetable mix in full sun. Water often, as pots dry out quickly, and feed regularly.