Cucurbit Cultivation

Sowing

Seed of most pumpkins and squash is usually viable for 4-5 years. Plants from older seed produce more fruit and less foliage. Seed from home-grown plants should not be reused as natural cross-fertilisation between different cultivars means that the offspring will be very variable.

The seed should be sown between mid April and mid May in warm (16-24°C) humid conditions. For the best plants, sow a single seed in small pot of peat-free multipurpose compost. Most seed will germinate within a few days, but with cultivars that are harder to germinate, provide gentle heat from below.
Once they have germinated, move the seedlings to a frost-free cloche or glasshouse to grow on. The cooler the temperature, the better the plants will be, but bear in mind that all pumpkins and squash are susceptible to frost.

Growing

Once the last frost is past at the end of May or June, the ground should be warm enough to plant out the young potted plants. Any good soil with plenty of garden compost added should provide ideal conditions for a good crop.

Space the plants about 1 metre apart, although trailing varieties may need more room. Until the plants spread out and cover the ground, keep the rows weed free with regular cultivation. Pinch out growth tips once the desired number of fruits has formed to restrict the size of the plant.

Water regularly, particularly in dry conditions. This is essential if large fruit is required. Reducing the number of fruit to one or two per plant will also ensure larger fruit.

Many pumpkins and squash take a minimum of 95 to 100 days to mature though some need between 120 and 130 days. In late September, remove excess foliage to give the fruit a better chance of ripening in the autumnal sun.

Harvest - a squash for all seasons

The squash year begins in July with courgettes, pattypans and other summer squashes. Picked small and immature, these fruits need to be eaten immediately. Autumn squashes, including marrows, acorn squash and spaghetti squash, are picked when fully ripe. Although they can be kept for short periods, their thin soft skin provides little protection and they should be eaten within a couple of months. With their tough waxy skin, winter squashes can be stored for up to a year. Butternuts, hubbards, and kabouchas can be made into warming soups and stews throughout the winter and spring, until the next year's courgettes are ready for harvest.

Ripe fruits sound hollow when gently tapped. They will continue to ripen if the weather is warm even when they are detached from the mother plant.

Cut the fruit from the plant with a small sharp knife, taking care to leave a 'handle', a small piece of stem, attached to the fruit.

Storage

Before storage, inspect the fruit carefully for damage and separate those that have bruises or damage to the outer skin. These should be used quickly. Undamaged fruit should be cleaned to remove any organisms that could cause rotting. Carefully sponging off the soil and plant debris should be sufficient to ensure the fruits last through the winter. Fruits that are to be stored must be exposed to the sun for ten days to allow the skin to 'cure' or harden further so that it forms a barrier that slows the rate of water loss during storage.

Keep over the winter in a cool frost-free place with good ventilation. Some cultivars keep better than others and those with harder skins at harvesting will keep the longest.

Take care to ensure that the fruits do not rot in the store, by checking them frequently. Discard any that show signs of rotting so that the infection does not spread to the whole store.

Long keepers include 'Rolet', 'Crown Prince' and Hubbard types such as 'Green Hubbard' and 'Blue Hubbard'. Summer squashes such as 'Patty Pan', 'Custard' and 'Scallopini' are not suitable for storage.

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