Thyme to sow: With a little forward planning, you can grow every herb going

Furnishing a herb garden is very much like furnishing a house. You need the big, permanent pieces of furniture, but you also need a few more evanescent things to add variety. Jekka McVicar, Queen of the Herbs, has put together an excellent Herb Starter Kit for gardeners who need guidance. She includes shrubby stalwarts such as 'Hidcote' lavender, rosemary, purple sage and the pretty little variegated thyme 'Silver Posie' among perennials such as chives, bronze fennel, pale green apple mint, wild strawberry and oregano. Planted together with parsley (a biennial) that would make a good-looking patch.

But you don't necessarily have to herd your herbs together in a single place. Variegated thyme can be used with pinks such as 'Hidcote' at the front of a border, spilling over onto a path. Rosemary, gently clipped, makes an excellent soft piece of topiary, among box balls and variegated myrtle (Luma apiculata 'Glanleam Gold'). Bronze fennel is a superb foliage plant, much in evidence at the Chelsea Flower Show this year, mixed with the brilliant red peony 'Buckeye Belle' and dark iris. Brian Halliwell once used it at Kew to underpin a mass planting of pale lemon tulips. That was a fabulous combination, but you need a lot of fennel. It's not difficult to grow from seed, though. Jekka has it at £1.70 a packet.

Herbs grow well in pots too. I still have the rosemary that spent the first six years of its life on a roof terrace where it was regularly bowled about in its pot by the wind. I tried weighting the pot with stones, covering the surface of the compost with them, but it still got thrown about. Liberated from its pot, it has now spread its long, lax arms over about four feet of bank. It's earnt the space.

Mediterranean herbs such as rosemary, thyme and marjoram are used to poor soil and drought conditions. Chives, wild strawberry and parsley like damper, richer living. If you have both sun and shade on a balcony or roof terrace, give the Mediterraneans the sun and keep the others in the shade. Parsley grows very well in pots, but the bigger the better. I grow ours in black plastic pots 28cm across, kept just outside the door. Biggish pots don't dry out as quickly as small ones and if you use a nitrogen-rich fertiliser when you water, the parsley grows strongly all season.

Parsley, which we think of as such an English herb, isn't. The Romans brought it over, along with chervil, chives, rue, fennel, rosemary, borage, sage and thyme. Were they with the troops on that first invasion in AD43? Or did the soldiers arrive without, unable to imagine a world where these things did not exist? We had mint in Britain of course (the source of a long-running joke in Asterix in Britain) and mint, sage, parsley and thyme are perhaps still the commonest herbs in most people's gardens. English cooking depends on them: sage stuffing with pork, parsley sauce with ham, lemon and thyme stuffing with lamb, as well as the ubiquitous mint sauce.

It's not too late to sow parsley, direct where you want it to grow (Jekka has both curled and French flat-leaved parsley at £1.50 a packet). It does not transplant well, because of its long, carrot-like tap roots. If you are sowing in a pot, water the compost before you sow, then sprinkle the seed as thinly as you can on the surface and cover with more compost, crumbled in your hand to get rid of lumps. Press the compost down with the flat of your hand (or the bottom of a pot) and leave the pot in a semi-shaded place where it will not dry out too quickly. Germination is slow. You may have to wait more than a month for seedlings to appear.

If leaves on established plants start to turn yellow, cut the stalks down to the base and feed with a liquid fertiliser. I stand my pots in a tray of water overnight, so the roots can pull in all the water they want. In the second year, the plants start pushing up flowers, as they want to set seed (parsley is a biennial, not a perennial). For a short time you can keep the leaves going by cutting out the flowering stems. In the end though, you have to chuck the whole lot. But by that time your new crop will already have been sown. Or should have been ...

Christopher Lloyd used to grow curly-leaved parsley in his flower borders, because he thought it was such a good foliage plant. You can do the same, but it might be safer to sow in a pot first, then tip the whole potful out into its place in the border, without disturbing the seedlings. Jekka used parsley well in her display at the Chelsea Flower Show this year, with clouds of yellow-flowered woad, hummocks of thyme, flat-faced pot marigolds, snowdrifts of the Crambe maritima that grows on our Dorset beaches, vast stands of angelica. And nettle.

I spend a lot of time getting rid of nettle. There's acres of the stuff round us, so no butterfly need go far in search of a place to lay her eggs. It's another thing the Romans brought us, probably as much for food as for medicine. Nettles are rich in iron and sodium and also contain a fair amount of protein; they fill the hungry gap in spring when winter supplies have been used up. Nettle tonics, made by brewing a handful of leaves in a pint of water, cleansed the blood, pepped you up, especially in spring.

Tons of dried nettle leaves used to be imported from Germany, until the Second World War put a sudden stop to supplies. Dr R A Butcher, appointed National Herb Organiser by the wartime government, set up country herb committees who organised the gathering of supplies. Ninety tons of dried nettle were gathered in 1942 (that's equivalent to about 720 tons of the fresh stuff). Most of it was used to extract the green dye used in great quantities in the camouflage industry.

Altogether, 750 tons of dried herbs (as well as 2000 tons of rose hips) were amassed by the herb committees. The West Country specialised in foxgloves (for the drug digitalis), belladonna came from Rutland and Sussex, male fern (a remedy for tapeworm) from Northumberland and Wales. Broom tops, burdock leaves and root, comfrey, dandelion, elder, hawthorn, lime flowers, raspberry leaves, root of valerian, yarrow, wormwood, all contributed to the war effort. A free medicine chest. Now we need to learn again how best to use it.