Courgettes are part of the same family as squashes and cucumbers; and of course, marrows, which are Cucurbits. It is actually classed as a fruit. You can get yellow and bulb shaped varieties too. You can also refer to Growing Marrow page.
They can be sown directly outdoors or in containers from late April onwards once the threat of frost has gone. You can sow indoors earlier; during March by using 3inch pots and sowing the seed sideways in compost. Sow two seeds in each pot and keep the stronger seedling. Propagate the pots or cover with clear plastic until the seedlings appear and keep the pots on a warm and sunny windowsill.
You can sow outdoors in a sunny position, once they have been hardened off during late April onwards, with well-rotted manure or compost. Courgette seeds should be sown on their side to prevent rotting, approximately an inch deep; sow two or three and then you can whittle down to leave the strongest if you wish.
Courgettes do produce quite a glut and so one or two plants should be ample for an average family. Allow a couple of feet between each plant, as they can grow pretty large and have large leaves. Keep an eye for powdery mildew on the leaves.
Courgettes are thirsty plants and will require plenty of water regularly; particularly during hot and dry spells, being careful not to wet the leaves to reduce the risk of powdery mildew, which is a fungal disease. You can also mulch the ground to hold in the moisture. Remove any affected leaves, which will give better air circulation to the plant also.
The courgette plant produces beautiful, big yellow flowers that are edible too. Once the fruits start to form, feed the plant with some tomato feed every couple of weeks.
When the courgette fruit forms, it is remarkably quick to grow. They can be harvested at approximately 4 inches long, or alternatively can be left to grow and mature, which then becomes a marrow. During the summer, you will likely be able to pick a few on a daily basis. Pick them regularly to encourage re-growth but also to keep them at their best as a courgette; they will soon quickly grow large if they are left.
The courgette plants will die off at the end of the season during early autumn. You can protect them to extend the cropping if you wish.
Courgettes can be eaten in a number of ways; both raw and cooked as well as the flowers, which can be stuffed or used as a garnish with salad. They can also be wilted in oil.
Courgettes are best fresh and will keep for approximately a week refrigerated or they can be frozen if they are blanched first.