I've always been crazy about fresh herbs—so crazy, in fact, that I used to raid the Cloisters gardens in Manhattan, stealing a sprig of oregano, rosemary, or thyme just to keep myself in supply.

Today I have no need for tactics like that. I'm lucky enough to have my own garden that's full of many of my favorites: thyme, savory, chives, purple sage, spearmint, lavender, and more. And for those herbs that I just can't get to thrive in my front yard, I have another convenient (and legitimate) source: the local supermarket. Nowadays, well-stocked groceries often carry herbs like tarragon and marjoram alongside favorites like basil and rosemary.

Such availability is a dream come true for me, but I've noticed that many people are intimidated by this abundance of choice. How many passionate cooks (professionals as well as amateurs) buy fresh herbs, use maybe a few sprigs, and then proceed to forget about the rest of the bunch until they're dried out, limp, or spoiled? Many, I know. Why do they let these wonderfully fragrant flavorings expire in the back of their refrigerators? Because they don't know how best to store and handle them, and perhaps because they're a little afraid of using them. What herbs go with what food? How do you use them other than as a sprinkle to decorate a dish? When and how should they be added during cooking?

Once you have the answers to those questions, which I'm about to give you, you'll find yourself reaching for that bundle of herbs more and more often, and throwing them out less and less.

Finding and buying fresh herbs

Supermarkets package fresh herbs in various ways: loose in small plastic boxes, fastened in bunches with rubber bands, or sometimes still growing in a pot. No matter the packaging, look for herbs with vibrant color and aroma (open up those boxes for a sniff), and avoid those that are limp or yellowing, have black spots, or don't smell totally fresh and appetizing. I like to buy field-grown basil, parsley, mint, cilantro, and dill when possible—as opposed to greenhouse grown—because they're so much more fragrant. You can recognize field-grown herbs by their larger, hardier stalks and leaves. Some chefs prefer the more tender greenhouse herbs because they make a lovely delicate garnish and because they're ready to use straight from the bag.

It's worth exploring other sources for herbs, too, such as Middle Eastern, Latin, and Asian markets, which often carry herbs of higher quality and at lower prices than the supermarket.

Fragile herbs need TLC

Hardy herbs like rosemary, marjoram, and sage will stay green and fragrant for a week or two, as long as they're refrigerated and don't get wet. But tender herbs, such as basil, dill, cilantro, tarragon, and chervil, need special attention so they don't blacken or freeze in the refrigerator.

To keep tender herbs at their best, remove any rubber bands or fasteners. Because the roots draw the moisture from the leaves, it's important to trim off the root ends and the lower parts of the stems to prevent the tops from wilting. If the roots are large and prominent, you can save them to flavor soups or stocks. (Southeast Asian cooks chop up cilantro roots along with the leaves, while Jewish cooks like to add parsley roots to chicken soup.)

To keep pesto bright and green, be sure your food processor blade is sharp so it cuts without crushing the ingredients (if not, bring it to a knife sharpener). Then add the ingredients in the proper order: fat first, herbs last. I start with the oil and then add the garlic and pine nuts, puréeing them completely. Finally, add the greens, processing them for as short a time as possible so they stay cool and maintain their color.

Try other herbs besides basil in pesto (an Italian word simply meaning paste). Make a Southwest pesto with cilantro, pumpkin seeds, garlic, and aged Monterey Jack or Asiago cheese and a little fresh green chile. In cold weather, I make a sage, parsley, and walnut pesto to stir into a bowl of hearty white bean soup.

Wrap the trimmed but unwashed herb bunches loosely in damp paper towels and put them in a heavy-duty zip-top bag filled with a little air, which cushions the herbs. Or even better, seal the towel-wrapped herbs neatly in a plastic container without crushing them. Store the herbs in the warmest part of the refrigerator, which is often the top shelf. Check the herbs daily, using those that look the least perky and discarding any that have begun to spoil.

Freezing fresh herbs generally turns them black and slimy, but if you protect them with a fat, by making a pesto (without the cheese) or an herb butter, for example, they'll be fine.

Wash herbs only when you're ready to use them, because excess moisture shortens their shelf life in the refrigerator. If I can get away without washing them at all, I do. Greenhouse herbs will be cleaner than field-grown and may not need washing. But if the herbs look or feel sandy, I wash them no matter their origin.

To wash herbs, put them in a large bowl of cool water and swish them to release grit. Lift the herbs out of the water with your hands, a sieve, or a skimmer. If you see a lot of grit on the bottom of the bowl, wash the herbs again in a fresh bowl of water. Spin them dry in a salad spinner or gently blot them dry by rolling them up in a clean towel.

Chop with a sharp knife or snip with scissors

A sharp knife is imperative for chopping herbs. A dull one will crush and bruise tender leaves, giving you blackened rather than green results. I use scissors to snip off small amounts of tender herbs, especially chives, whose stringy fibers are difficult to cut cleanly with a knife.

The more tender the herb, the closer to cooking time you'll need to chop it. If you chop in advance, cover the herbs with plastic wrap punctured with a few air holes and refrigerate them. You can save leftover chopped herbs for a day or so, but sniff them before using, especially parsley, cilantro, basil, and dill, which are highly perishable when chopped.

Whether you add the herb whole or chopped, or at the start of cooking rather than at the end, depends on both the herb and the effect you want.

If you want the herb to contribute a rounded background flavor, add a sprig at the beginning of cooking. Strong, resinous herbs like marjoram, thyme, and savory do best when allowed to mellow during the cooking process. To gently release the flavor oils of an herb in a slow-cooking sauce, soup, or stew, lightly crush the sprig before adding it to the liquid. Leaving the leaves on the stem makes it easy to remove the whole herb later.

For a more forthright herb flavor, chop the herb and add it near the end of cooking. The pungent, unmistakable aroma of chopped cilantro seems to dissipate quickly, so I stir it in directly after cooking, which also helps it to retain its bright green color. Sometimes you'll want to emphasize an herb's flavor by adding it both before and after cooking. For my marinara sauce, I add whole sprigs of basil at the start, and then I liven up the basil flavor by adding finely shredded leaves just before taking the sauce off the heat.

Take advantage of the whole herb

When a recipe calls for only one part of the herb plant, I make a point of reserving the remains for another use. If you are unsure of which herbs go best with which foods, see Herb and food pairings for some time-honored combinations.

Save tender stems for stocks and woody ones for the grill. Add tender herb stems in small quantities for a mild foundation flavor in chicken stock or fish fumet. Don't get carried away, especially with herbs that contain a lot of chlorophyll (the green coloring) like parsley, cilantro, and dill. Woody stems of strong, resinous herbs can be used instead of wood chips on the grill. Try hot-smoking (cooking slowly in a covered grill so the smoke penetrates the food) a New York sirloin strip steak over thick rosemary stems, as I used to in my restaurant days. Stems from thyme, sage, marjoram, rosemary, and savory all work well.

Deep-fry herb leaves for an elegant, crunchy garnish. Fried flat-leaf or curly parsley is a classic partner for fried fish and seafood. I garnish crab cakes served over a fresh tomato sauce with crispy and tasty fried lovage leaves. Whole sage leaves dipped in a simple Italian flour and water batter, called a pastella, and then fried in olive oil, are a traditional complement to fritto misto (batter-fried meat, seafood, and vegetables).

Search out herb blossoms in season. Especially delicious are lavender-blue chive blossoms, petals separated and sprinkled on a cold vichyssoise. Sweetly perfumed blue-violet sage and borage blossoms make a seasonal salad garnish. Other blossoms, like tiny white thyme, lavender-blue summer savory, and purple rosemary, taste wonderful mixed with chives and browned butter and then tossed with fresh pasta; sprinkle with grated Parmesan or crumbled fresh goat cheese. I don't like basil or marjoram blossoms as they tend to be bitter, and the pretty white blossoms of Chinese or garlic chives are too tough to eat.