Anna Pavord: 'Sow courgettes now for infinite variety in your outside borders'

Macho monster-marrow growers are missing out says our gardening correspondent

A flowering zucchini in the vegetable garden (Alamy)

Courgettes, as all gardeners find, have a frightening capacity to turn into marrows if you go away at the wrong time. Some gardeners love marrows – especially those who grow them to show at gatherings where monster veg have heroic status. There is always a place for an overgrown marrow.

The growers at these gatherings stand around in knots, arms folded, sleeves rolled up, leaning back slightly; the stance of men who know exactly where they fit in the great scheme of things. The conversation is only of their vegetable charges. "I fancy he's lost a bit of weight overnight. I'm not happy." You won't find men like these messing about with courgettes.

But in the kitchen there is a great deal to recommend them. And now is the time to sow, if you haven't already. There is no point in being too quick off the mark. Young plants are tender and can't go outside until all danger of frost has passed. You can start courgettes off on a window ledge if you don't have a greenhouse. Set one seed on edge in a 7cm/3in pot of compost, water the pot and cover it with a bag or a piece of glass till the seed has germinated. The temperature needs to be hovering around 13C/56F. If it's consistently lower than this, the seed will rot off in the damp compost.

Leave the baby plant in the pot until it's safe to plant it out. By this time it will probably have three or four proper leaves. They will put up with a certain amount of shade, but like rich, moisture-retentive soil. Courgettes are thirsty beasts so you must keep them well watered. The traditional method is to build a shallow, circular wall of earth about 60cm/24in in diameter around each plant. When you water, the water stays where you want it. Mulching is also very beneficial. It suppresses weeds as well as conserving moisture.

They need space, too, so allow at least 1-1.2m/3-4ft each way. I plant them in a long border between tall drums of peas and sweet peas. You need to settle in the young plants properly (watering and feeding them till they are growing away strongly), but after that, they don't need much looking after. When they are established, their huge leaves will smother all competition from weeds and also help to prevent loss of moisture from the soil. But for plants to crop well, they must never be short of water.

Last season, I planted some leftover courgette plants in pots just a little more than 30cm/12in across, to see how they would fare. They started off well, produced their first crops at the same time as the plants in the ground, but then ran out of steam. No amount of watering and feeding could persuade them to continue. In a bigger pot, perhaps the harvest would have been longer.

There are varieties, such as "Black Forest" (Thompson & Morgan, £3.39 for four seeds) that are recommended for growing in containers. But that's because they climb rather than bush out. You'd need a biggish container and plenty of feeding to keep it cropping over a long period. You'd also need a strong support, trellis perhaps, to which you could tie the stems as they grow. There's a yellow-fruited climbing variety called "Shooting Star" (T&M, £2.49 for eight seeds) that you could grow alongside for contrast.

My failsafe courgette is "Defender" (Chiltern Seeds, £2.99 for 20 seeds) which is both early and prolific. > Quantity isn't as important as quality, but "Defender" is excellent in both respects, with dark green, shiny fruit and a delicious taste. The key of course is not to let the fruit get too large. As with sweet peas, harvesting constantly persuades the plant to keep on producing. And the advantage of growing your own is that you can pick them when they are only finger-sized. This is when they are at their most ambrosial.

Towards the end of the summer, courgette plants may start to look mildewed and then production slows down. The best defence is to plant where plenty of air blows through the stems and foliage. Against cucumber mosaic virus, alas, there is no defence. But some varieties (such as "Defender") have a certain amount of resistance bred into them.

But a lot of the fun of growing your own fruit and vegetables is experimenting with unusual varieties. I've tried "Romanesco", which has heavily ribbed fruit of quite a pale green. The flowers are enormous, so it's a useful courgette to grow if you like the flowers battered or stuffed. "Bianca de Trieste" is even paler, with smooth, fat fruits – very prolific. Like "Romanesco", it produces big flowers. Pick the male flowers for the kitchen. Then you don't miss out on any fruit. They will be held on long straight stems, with no imminent swelling behind.

Gardeners seem to be offered more courgettes with Italian names than French ones, which might be because companies such as Seeds of Italy have taken more trouble to tell us about the Italian kinds. Still, we generally persist in calling these vegetables courgettes rather than zucchini, even though the Oxford English Dictionary has an earlier entry for zucchini (1929) than it does for courgette (1931).

I think courgette stuck because of Elizabeth David and her French Country Cooking (1951). She writes there about bringing courgettes back to Britain from France, so I'm supposing that they weren't things you could buy easily then. By the late 1950s, though, they must have been more firmly established, as Sunday newspapers started to publish recipes that included them. Courgettes stuffed with shrimps appeared in 1958.

There's no mention of courgettes in The Vegetable Garden by M Vilmorin-Andrieux, head of the famous French seed company and published in an English translation in 1905. But in section III of the chapter on pumpkins, there's a description of the "Italian vegetable marrow" which sounds very much like the "Romanesco" courgette.

"A very distinct variety," writes Vilmorin-Andrieux. "Stems not running… producing numerous leaves of a dark green colour, large, and deeply cut into five or six lobes. Fruit… furrowed by five ribs which are most prominent on the part next the stalk… All through Italy the fruit is eaten quite young, when it is hardly the size of a small cucumber."

The Vilmorin seed company still flourishes and I went on to its web site (vilmorin-jardin.fr) to see if there, at least, there would be listed French- sounding, rather than Italian-sounding courgettes. But of the 11 varieties offered, only one "Courgette de Nice a Fruit Rond" had an unmistakeably French provenance. From now on, I'm going to call courgettes zucchini. It seems only fair.

WEEKEND WORK

WHAT TO DO

* Plant up hanging baskets, leaving a saucer-shaped dip in the compost to make watering easier. Leave the basket in a greenhouse or sheltered place indoors until all danger of frost has passed.

* Seedlings at various stages of growth dominate at this time of the year. My cobaeas are growing too fast, the tomatoes not fast enough. There will soon be a traffic jam on the windowsill of the kitchen. I have just sown Dianthus 'Stripes and Picotees' (T&M, £3.99) to line out along a path. Germination takes from 7-14 days, then the seedlings have to be pricked out into 8cm/3in pots to grow on before they can be planted out.

* Sift fresh soil over clumps of saxifrage where there are black or bare patches. Do the same for auriculas which have a tendency to heave themselves out of the soil.

WHAT TO SEE

* Three private London squares are opening their gates tomorrow to raise funds for the National Gardens Scheme. The Arundel and Ladbroke Gardens (W11) are planted in woodland style. Cadogan Place South (SW1) was developed at the end of the 18th century and has wonderful magnolias. And Ecclestone Square (SW1) was masterminded by the photographer Roger Phillips