Grow your own: Carrots

With colourful roots rich in Vitamin A, carrots are among my favourite vegetables. Whole baby carrots, or large ones finely grated, are delicious in salads; sliced carrots are an important ingredient for winter casseroles; and small whole ones combine well with almost any other vegetable at any time of year. Home-grown carrots have a far better flavour than shop-bought ones and you can be certain that they are free from any chemical residues.

I always sow some early carrots in my walk-in polytunnel at the end of winter, but early June is the most important time for sowing the seed. This is because much of the vegetable plot has been cropped, we've put out the half-hardies and, with a lull from all the spring growing activity, it's good to be starting something new. In addition, sowing carrots in June avoids a lot of the root fly damage that can lead to maggoty carrots that are of little use in the kitchen. You can eat the roots from this sowing immediately after lifting through late summer and early autumn. Store them in boxes of sand in a frost-free place to use up until the end of winter, or freeze them whole or sliced and you could have supplies through to next summer.

Carrots grow well in pots, such as these deep, recycled fertiliser buckets

If you are an organic gardener, there are steps you can take to reduce root fly attack. It's certainly helpful to rotate crops so that carrots grow no more than once in three years on one patch of land, and winter digging will ensure no carrots are left in the ground to harbour pests through the cold months. Sowing a sprinkling of spring onion seed in among the carrots can help mask their scent and keep the fly away, as does growing a row of onions alongside. The female pest flies low over the ground, so surrounding a bed of carrots with an impenetrable barrier about 75cm (2½ft) high is quite effective.

I find the best way to overcome the problem, however, is to grow carrots in a block of short rows, rather than one long row, and cover with a fine insect-proof mesh immediately after sowing and right up until harvest (try Micromesh from Haxnicks: 0845 241 1555). Hold the material down at the sides with a few spare bricks and make sure it is wide enough to still cover the bed completely when the growing carrot leaves lift it up.

Root fly is not the only pest – slugs can devour carrot seedlings. Their attack is worse in a damp season and so usually more of a problem in spring than with June sowings. I like to keep the carrot bed well away from places where slugs can hide, such as borders with ground cover. Watch out for slugs and remove any you spot on a new carrot bed. You could try leaving a few roof tiles, logs or outer lettuce leaves around – ideal hiding places for the pests – which you can then collect and destroy.

I place seed in one hand and trickle just a few seeds per 2.5cm (1in) along the bottom of the drill with the fingers and thumb of the other hand. Place marker sticks with labels at the ends of each row, refill the drills with soil and water well with the rose on the can, then cover with mesh.

Carrots shouldn't need a lot of aftercare, other than watering in dry spells and occasional weeding. Do this in the evening to prevent root flies from smelling bruised foliage, and water afterwards. You can thin out young carrots for eating raw in salads, or for cooking, to give room for other roots to develop to full size.

I lift my crop, a row at a time, in October, wash the roots with the garden hose, wring off the leafy tops and sort the carrots. I pack undamaged roots of a good size in boxes filled with slightly damp sand and store in the garage. If the roots are too small to store, I wash, top, tail and scrape them, then blanch and freeze them for cooking. I put aside damaged roots for early eating and scrape, slice and blanch all the good parts for freezing. The latter will provide home-grown carrots until next season's early crop is ready to eat.

Carrots with extra-long, tapering roots, such as 'St Valery', are popular with gardeners keen on entering their vegetables in horticultural shows, but need deep, fertile soil for good results and are rather slow-growing. Varieties that are stump-rooted with longish plump roots with blunt ends are equally good to eat as baby carrots or as larger stored roots.

Yellow carrot Creme de Lite

Most varieties recommended for June sowing are listed as maincrop, but you will find 'Early Nantes 5' and similar varieties excellent for early spring sowing as well as for use as a maincrop. I like orange carrots but there are many others. Purple, red, yellow and cream carrots may seem like novelties dreamed up by plant breeders but, in fact, purple and yellow types were eaten 1,000 years ago so these are natural colours for carrots. Research now shows that such plant pigments have health benefits; for example, red carrots contain lycopene that can protect against heart disease, while purple carrots have natural anthocyanins, which are antioxidants. So, why not give them a try? There are mixtures such as 'Rainbow' or 'Harlequin' or try single colours such as 'Red Samurai', 'Purple Dragon' or 'Purple Haze'. Also available is pale-yellow 'Creme de Lite'.

2 Choose a site that has not been manured recently.

3 Sow in a block of several short rows, rather than in one or two long ones.

4 Prepare the site 10-14 days before sowing carrots to allow weed seeds to germinate, then you can remove the weed seedlings.

5 When weeding, hoe and rake over only the top 2.5cm (1in) or so to remove the weeds, but do not disturb the lower soil.

6 Sow thinly so you can harvest baby-sized carrots to eat either raw or cooked.

7 Use a soil-based compost for carrots grown in containers, as this makes watering easier.

8 Cover the bed or container with fine mesh to allow water to penetrate while keeping root fly at bay.

9 Keep watered in dry spells for quick germination and early growth.

10 Weed between and thin seedlings in the evenings only; water before, if needed, and immediately afterwards.

2 'Bangor' F1 hybrid
One of the best maincrop varieties producing heavy yield of excellent quality.

3 'Early Nantes 5'
Cylindrical with superb colour and flavour; good under glass for early sowing as well as a maincrop.

4 'Eskimo'
NIAB-recommended and highly tolerant of cold - leave it in the ground all winter on well-drained soil.

5 'Flyaway' F1 hybrid
Like 'Autumn King' and, as its name suggests, it has good resistance to root fly. You can sow this variety early.

6 'Kingston' F1 hybrid
Produces large roots of excellent colour and is good for storing and showing.

7 'Maestro' F1 hybrid
NIAB-recommended with disease-resistance, good health and vigour, and good for organic growing.

8 'Parmex'
NIAB-recommended with round roots that are excellent for pulling and eating young. It's also good in containers.

9 'Resistafly'
F1 hybrid British-bred with resistance to root fly. This 'Nantes' type produces roots of superb colour and taste.

10 'Sytan'
Combines high resistance to root fly with exceptional taste.