Cucurbits

Introduction

Cucurbits include courgettes and summer squash(Cucurbita pepo), pumpkins (Cucurbita maxima) and winter squash ( Cucurbita maxima & Cucurbita moschata). These are frost-tender fruiting vegetables. Other members of this family include melons and cucumbers, for which greenhouse propagation is needed. For all varieties, seeds are best sown indoors from late April onwards, and transplanted outdoors from mid-May. From mid-May onwards, seeds can also be sown outdoors. All cucurbits need a highly fertile soil, enriched with manure as much as possible.

Courgettes and summer squash

Courgette and summer squash plants generally grow as small bushes. They can be placed 60cm (2 feet) apart. They will produce fruit of many shapes in green or yellow that is best picked when small and immature. Cropping can begin as little as 5 weeks after planting and will continue until overnight temperatures are below 4°C.

Pumpkins and winter squash

Pumpkins and winter squash need a lot of space; they should be planted 2m (6 feet) apart. They grow as large straggling vines, producing fruits from 1kg (2.2lb) in weight up to hundreds of kilograms when grown for competition. Winter squash have been bred to be kept before eating and some varieties will keep until the following spring. Winter squash need not be harvested until frosts threaten, but may be picked earlier if smaller more manageable fruits are needed. This will also encourage the plant to produce more fruits. When harvesting, cut off fruits with as long a stem as possible. Place somewhere warm and dry for a week to "cure" the squash, then transfer to a cooler but frost-free long term storage area. For most varieties the flavour improves with storage.

Problems

There are few specific pathogens for cucurbits although cucumber mosaic virus can cause problems, This causes mottling of the leaves and reduces plant vitality, but is not something I have suffered problems with. Many resistant cultivars are available. Young plants may be attacked by slugs and snails, appropriate chemical control should be used. A late frost can also damage plants; check weather forecasts and cover plants with horticultural fleece or similar. From late August onwards, powdery mildew can be a big problem for summer squash and courgettes, affecting entire plants. It can also kill leaves on winter squash.