As the gardening season comes to a close, nature calls us to put away as much as possible to eat over the cold winter. Pickles, tomato sauce, jams, and dried herbs for tea, medicine, and flavoring our foods are all easy and satisfying to accomplish. Here are a handful of useful tips you can use to keep your plants healthy, and get the best quality herbs to last you through the year.
When you begin harvesting during your growing season varies widely from herb to herb. Cool season herbs like cilantro, parsley, and dill to name a few should be harvested in the spring before they start to bolt (which can make them bitter.) I usually eat these herbs as much as I can fresh in spring, and save my fall planting of them for preserving for the winter.
The majority of herbs are heat loving, which means you can harvest gently throughout the summer season and in the fall, cut much, if not all of it back for preserving. For specific crops, see our growing guides for details on whether your herb in question is cool or warm season, and whether it is perennial or annual, which is helpful to know so you don’t over-harvest your perennials, which could leave them vulnerable and not able to come up the following spring depending on your growing zone.
Different types of plants have different preferred methods of harvesting. Leafy annuals like basil will form bushier plants by pinching off leaves from the tips of the stems. These are going to be your first harvest, and as your plants get bigger you can start taking more and more leaves. When you pinch your plants, be sure to clip stems close to a leaf-pair so as not to leave a stub. Herbs with long stems like cilantro, parsley, lavender, and rosemary should be cut near the base of the plant – about an inch from the ground. Take your cuttings of long-stemmed herbs from the outside of the plant, as most of these will be producing fresh growth from the center crown. Leafy perennial herbs such as oregano, thyme, sage, and tarragon can be harvested by the stem or sprig.
With the exception of at the end of the season when you are harvesting before you lose the plant to frost, you never want to harvest more than one third of the entire aerial growth at one time. This ensures that the plant will have plenty of leaves to regrow itself afterward. Some perennial herbs will overwinter nicely in climates with mild winters, so sticking to the one third rule for those may mean you can have fresh herbs all winter.
There are some exceptions to the one third rule though! Chives, for example, grow back faster if all of the leaves are cut off within an inch to a half inch from the ground. Species in the mint family (including catnip, citronella, and lemon balm) regrow more efficiently if all of the stems are harvested at once – cut above the first or second set of leaves from the base of the crown.
There are many herbs that we use multiple parts of, for multiple purposes. Knowing when and how to harvest these plants for your specific purpose may require a bit of finesse. Cilantro, for example, has a short life-span that progresses rapidly from seedling to flower and seed. If your goal is to harvest cilantro for its leaves, you’ll have to keep an eye on these plants. They like to flower quickly, and so we often succession plant cilantro for using leaves, but when it is just too hot and they bolt (flower), you get a lovely second crop of coriander seeds! This is the case for dill, fennel, and many others. Seeds often have very exciting flavors that can liven up a dish. If you are interested in making your own home remedies too, many parts of the plant might be utilized, from the flowers to the roots, depending on the plant or medicine being made.
When is the End of the Season, Really?
You can and should harvest all of your annual herbs before your seasonal first frost. As I’ve mentioned previously though, some perennial herbs can be harvested year-round like cold-hardy thyme and rosemary in most zones. Other perennial herbs should be allowed a rest period before the first frost so the plants aren’t stressed before they go into dormancy. For leafy perennials like sage and mint, you’ll want to do your last big harvest about two months before the first expected frost then harvest only lightly from that point on unless your herbs are in pots and you plan to bring them inside for the winter.
This is probably the most popular and widely-used method for preservation of harvested herbs. Drying works well for woody-stemmed herbs like rosemary, oregano, and lavender. Our Grannies did it best and you can too by simply cutting off long stems, bundling, and hanging them up to dry. Another good way to hang and dry is to loosely bundle stems and leaves into brown paper bags with holes punched into all sides. There are also nifty net herb drying shelves you can purchase at a reasonable price that hang and have a lot of surface area for drying a lot of herbs at once. No matter how you air dry, set your plant material in an out of the way place, out of direct sunlight, and with good ventilation.
When harvesting herbs for drying, make certain that they are free of dew to avoid mold growth.
Alternately, you can use a food dehydrator to quickly preserve your fresh herbs without the risk of contamination. These handy machines have a long list of other great uses as well.
Oven drying is not generally recommended because they temperature can’t get low enough to avoid destroying the herbs volatile oils and losing their flavor.
Preserving: Oil and Butter
Add cut herbs to olive oil or make herb-flavored butters to preserve them. This method cuts down on wilting and discoloration, and seals in flavors very nicely. Just remember that your herbs need to be very dry with no drops of water left on them when they are added to oil, otherwise you run the risk of bacterial contamination. When use this technique, I keep both the butter and oil I make in the refrigerator waiting for use. Refrigerated, butter will last at least two months, and oil will last 3-6 months. Try herbed butters in pasta, on baked potatoes, and for sautéing veggies. Herbed oils are my favorite for making salad dressings with, and for coating veggies before roasting.
Herbs are amazing preserved with vinegar. Save bottles from kombucha, dressings, or just use good ol’ mason jars for this method. Infused vinegars are so easy and versatile. Simply add your fresh herbs, -good candidates are rosemary, tarragon, or basil- to clean glass bottles and fill with a vinegar of your choice. Remember that your herbs will have to compete with the flavor of the vinegar they are stored in. Try mild white vinegar for more delicate herbs. For powerful herbs like rosemary or basil, use full-bodied vinegar like apple cider vinegar. Experimenting with this technique is super fun. Once you start, you won’t stop! Try adding fruit like raspberries, strawberries, and plums. Infused vinegars add vibrant flavor to all kinds of dishes, salads, pasta, veggies, you name it, you should try it!
For tender herbs and herbs with low oil content, like basil and parsley, freezing them tends to preserve their flavors better than drying. Here are a few excellent methods for doing this:
*Pesto! While the classic is made with basil, I encourage you to branch out. Arugula, cilantro, parsley, dandelion, and a mixed pesto with a sprig of everything from the herb garden are all delicious and worth making for eating throughout the year. I like to freeze mine in ice cube trays, and then wrap each pesto cube in a piece of wax paper all then put in freezer bags for the long haul. This makes it easy for me to grab a cube or two for my recipes.
*If you would like to preserve your herbs in whole form, you can paint the leaves with oil and store them flat in a freezer bag.
*A few steps short of pesto, you can chop up your herbs in a food processor or blender with a little bit of oil to form a paste. Freeze like you would with pesto, then when you’re ready to use them, pull however much you need and replace the rest back in the freezer.
*If you are on an oil-free diet, you can chop your herbs to desired texture, fill your ice cube trays, and then fill the trays with water to cover the herbs. When you’re ready to use them, simply pop out a cube or two and add to your recipe as needed.
Preserving: Salt and Sugar
Use salt to preserve herbs like rosemary, tarragon, marjoram, and oregano. Alternate layers of salt and whole leaves in a jar (or other resealable container) pressing firmly between layers until the jar is full. Alternately, add about 6 tablespoons of herbs to one cup of coarse ground salt in a blender and mix until well incorporated. Store salted herbs in air-tight containers until ready to use. You can use your herb-incorporated salt in recipes just like you would a garlic salt or celery salt.
For sweet herbs like mint, use sugar instead of salt for a flavorful treat! Mint sugar is my favorite in tea! I also love lavender in sugar this way too.
I hope this will get you inspired to grow harvest, and most importantly, enjoy some herbs! The world of herbs is wide and exciting, with an almost endless array of applications. Flavor, medicine, beneficial insect attracting, pest control, what are your favorite herbs and uses?
Written by Sow True Seed's Education Director, Angie Lavezzo.