Squash and pumpkins are all members of the same plant family and come in all sorts of shapes, sizes and colours. While they can take up a lot of space, this is a worthwhile polytunnel crop and many squash will benefit from the conditions offered inside your tunnel. These versatile fruits can be used in a wide range of recipes.
Squash and pumpkins are usually divided into two broad groups. There are summer squash and winter squash. All squash and pumpkin seeds are usually sown in April or May indoors and are planted out in a polytunnel or outdoors in a sunny portion of a garden as soon as the weather warms in around June. These plants will germinate readily and will grow quickly so it is best to start them in larger pots than would be used for most seedlings.
To save space, it is best to support vining squash and pumpkins on trellising or some other form of support rigged to the crop bars in your polytunnel. Make planting pockets and remember that these are plants that require quite a lot of space to mature. Make planting pockets of good quality compost or well rotted manure around 90cm apart for bush varieties and a little further apart for those with a vigorous vining habit. Planting pockets should be around the spade's depth and width and will help to feed these hungry plants. An organic mulch will also help to add fertility to the soil. Remember to harden off your plants before moving them to their final growing positions.
For additional fertiliser when the fruits first begin to swell, consider a good, organic liquid feed such as a comfrey or compost tea. If pollination is not taking place, you can increase pollination rates by taking a male flower and pressing it to the centre of a female flower. (Female flowers have the swellings at their bases that will become the fruits.) Excess male flowers can be eaten in a range of recipes.
Remove leaves later in summer to allow light to reach squash and ripen them more quickly. Large squash and pumpkins should be held off the ground with a tile or similar so they do not sit on damp soil and rot. Always try to water squash from below and try not to get water on the stems and foliage.
Nasturtiums are an excellent companion plant for squash. They are also an edible plant and can be a good addition to your kitchen garden.
Summer squashes, such as small patty pan squashes, are treated like courgettes and are harvested while the fruits are still immature, in the summer and early autumn, while winter squashes and pumpkins are left to mature on the vine and harvested before the first frost strikes.