Fresh herbs can turn a weeknight supper into a masterpiece. Make a paste of chives, fresh rosemary, garlic and olive oil, and rub it into a pork roast the night before you cook it. Snip some fresh parsley to sprinkle over your pasta sauce. Dice fresh basil to sprinkle over heirloom tomatoes. And when the herbs are snipped fresh from your own kitchen garden ... well, now we're talking masterpiece.

Herbs are usually the leafy portion of a plant. Spices come from the bark, buds, fruit, roots, seeds or resin. For example, coriander seeds are a spice, but the leaves are the herb we know as cilantro.

If you plan to use fresh herbs within a day, stand them in a vase of water to keep them fresh. If you need to keep herbs fresh longer than a day, place them in an open plastic bag with a damp towel and refrigerate.

Most herbs can be dried for long storage. The easiest way to dry herbs is to tie a bunch together with a piece of string and hang them upside down in a dark, dry place.

Tarragon and chives freeze well. Just rinse them off, dice them and toss them into a plastic storage bag before freezing. Leafy herbs such as cilantro and parsley are better frozen in water. They will turn mushy when thawed, but you can still use them to flavor liquids.

It's best to adjust seasonings at the end of a long cooking time to avoid overseasoning a dish. Also, some herbs and spices turn bitter during long cooking, and others lose their flavor altogether.

When substituting dried herbs for fresh in a recipe, use about one-third as much as you would fresh.

Sources: "The Complete Idiot's Guide to Spices & Herbs: A Savory Guide to Spicing Up Your Favorite Dishes" by Leslie Bilderback; "The New Food Lover's Companion" by Sharon Tyler Herbst and Ron Herbst