Twenty years ago, when the only green herb in a British supermarket was parsley, Jekka McVicar started selling herbs from her back yard. Now she has the largest herb collection in the U.K., and she and her nursery are institutions.

She's the author of Jekka's Herb Cookbook.

Lynne Rossetto Kasper: We are coming to you for inspiration for spring planting.

Jekka McVicar

Jekka McVicar: Some of the best things to grow in the spring are the what I call the salad herbs, because they're so quick and so rewarding. The fact you can create and eat your own produce within 28 days of sewing is just fantastic.

One that I really love is mustard because you get all these different colored leaves and different kinds of flavors. You can add it to stir-fry dishes, you can add it to salads, you can really make your packed sandwiches zing when you go to work.

The ones to look for are red frills mustard (which starts off tasting rather like new potatoes) and also a yellow mustard. You can actually also now buy a mixed mustard leaf seed. You can get red leaves, green leaves, yellow leaves, round leaves, serrated leaves, but they're all mustard flavored.

And prepare your ground well. The soil, remember, is the engine of any garden. So if you're using a potting compost, use a good potting compost -- the best you can buy. Don't skimp, because that's a waste of the money you spent buying seeds.

Do you know how to check the warmth of the soil?

LRK: No. How?

JM: Well, what you have to do is take your knickers down and sit on the soil. If it's warm enough, you'll know.

But if you have an allotment, you can't go around doing that kind of thing. So what you do is stick your elbow in, because your elbow is much more sensitive than your hands.

LRK: So if it feels comfortable to your elbow, the soil's warm enough for you to plant?

JM: Right. Because think about what seeds need to germinate: warmth, light and water. If your seed's too cold, it will close down.

Jekka McVicar's recipe for Mustard-Leaf Sauce

The other thing is watering and feeding. Do not let your compost dry out, because that will make the leaves tough and bitter. The sun can get a bit intense, so a bit of partial shade is really good. I grow my mustards in semi-shade.

Another tip: Water before you go to work -- not when you come home. You need to give it a good watering before a hot day to prevent it from drying out. If you water after work, temperatures drop at night and your plants sit there soaking.

LRK: And they're probably going to rot.

JM: Yes. Quite often they do.

LRK: How do you fertilize?

JM: Here at the nursery, we feed every Friday. It's a liquid solution made from seaweed that is not exactly a fertilizer; it's more of a tonic. It's like you taking multi-vitamins.

It's high in nitrogen and prevents plants from growing too fast. It would be like giving a teenager alcohol, and you know how stupid they get. Well, it's exactly the same way with a plant. It goes "Ooh, wow" and grows too tall, too soft and then keels over. The tonic ensures they grow at the right pace.