Fresh herbs should be eaten soon after they are picked. You can extend the life of fresh herbs by knowing the proper way to store different types. There is no one suitable way to store all types of herbs.
When selecting fresh herbs, look for plants with a uniform color and few dark or yellow spots. If you can, smell them to determine freshness. If you grow your own, common wisdom is to cut them in the morning after the dew has dried. This is when their aromatic oils are said to be strongest.
Basil and Mint
Treat basil and mint as you would a bouquet of flowers. If you bought them in a store, trim the bottom of the stalks, especially if these are brown or dry. Place them in a container with water and leave on the windowsill or on the kitchen counter. Change the water every day or so. They will keep for a few days or up to two weeks, depending on how fresh they were to begin with.
Cilantro and Parsley
Cilantro and parsley should also be treated like a flower bouquet. Trim the bottom of the stems and place in a jar of water. Cover the leaves with a plastic bag or paper towels and place them in the refrigerator door, which is a little warmer than the rest of the fridge. These herbs can last two weeks or more if they were very fresh when placed in water.
Alternatively, you can wrap these herbs in damp paper towels and put them inside a plastic bag inside the refrigerator.
Short-stemmed herbs like thyme, dill, rosemary and sage should not be treated like a bouquet. Instead, loosely wrap them in a paper towel or plastic wrap and place them in the fridge. These herbs are sensitive to moisture and should be kept dry. The paper towel will keep them dry and keep them from getting moldy. If they come wet from the store, dry them thoroughly on paper towels or in a salad spinner before storing.
Traditional methods advise against washing fresh herbs, arguing that you will remove the flavorful aromatic oils. Most modern cooks and health agencies, however, tell you to wash them. If the herbs contain any sand or grit or if they come from the store, it is probably best to wash them. Submerge them in a cool water bath and remove any grit. Dry completely with paper towels or a salad spinner.