Grow courgettes

Courgettes are attractive and productive plants, generally easy to grow and are one of the best to grow in large pots on the patio.
It is worth spelling out the main problems and how you can avoid them before looking at growing them.
The first main problem you may encounter is that your plants decide to only produce male flowers. These will not lead to courgettes – although they are good battered and fried. They are easy to identify because they have a relatively thin stem behind them and no embryonic courgette. Cool weather, early in the season, may be the cause.
Next, if female flowers are produced, it may be too cold for them to be pollinated well and any developing fruits rot off. This is especially common if the weather is cold and wet, causing the flowers to start to rot, spreading into the fruits.

Diseases
Two diseases might crop up. The first is mildew, which starts as a greyish, powdery coating, getting worse so the whole leaf can turn white. Don’t confuse this with the natural silvery patches on the leaves. Mildew is most common when plants are dry at the roots. It is most likely to be a problem when plants get old and large, and have a massive water requirement which you may not be able to keep up with. You can spray with a fungicide to prevent it but once the leaves are mildewed, there is no cure, so just take them off and make sure the plants are well watered and fed.
The other disease is cucumber mosaic virus (right) which spreads from plant to plant by aphids. The new leaves of affected plants will be small, stunted and mottled and yellow and new fruits will be blotchy in colour and frequently deformed. Plants cannot be cured and should be disposed of.

New varities
Fortunately there are certain varieties to help you beat these problems. Some courgettes, particularly ‘Defender’ and ‘Primula’, are resistant to virus infection.  Many varieties are resistant to mildew, including ‘Firenze’ and ‘Tosca’. Plant breeders have been looking at other useful features too – modern varieties include almost spineless ‘Tristan’ and ‘Endurance’, which makes harvesting less painful, and others, including ‘Picchio’ which are compact and display the fruit better.
Varieties have been introduced which produce crops without pollination, to get over the problem of all male flowers and poor pollination early in the season. They include ‘Parthenon’ (left) and ‘Cavili’, and are worth
a try.
Courgettes are not known for their flavour but some gardeners rate the pale, ‘Lebanese’ types tops so you could try ‘Clarion’ or ‘Cavili’. Remember that not all courgettes are long and thin, many are round and these are perfect for stuffing. Not all the plants are compact – look out for the new ‘Black Forest’ which is a compact climber – perfect for the patio where you can grow it in a pot and tie it to a trellis.

Growing courgettes
Start your seeds off now, Sow one or two seeds in each pot and pinch out the spare seedling if both grow. Keep in good light in a warm place for germination. Once the seedlings appear they grow quickly – it is important they are in good light or they will get spindly and are likely to snap off. After two or three weeks, they are ready to plant out, at the end of May, when there should be no more severe frosts.
Courgettes like moist, rich soil so dig in lots of compost and manure. If growing on the patio, put one plant in a pot no smaller than 25cm (10in) in diameter or two plants in a growing bag. Water liberally as they grow and give liquid fertiliser once a week. They enjoy warmth and sunshine. Harvest at a small size, while they are fresh and tender. The more you pick, the more you will get. If you leave one or two to develop into marrows the plants will be less productive.