Harvesting and Preserving Medicinal Herbs
admin March 16th, 2011
Note: This is a re-run from a few years ago, but I was thinking about the beginning of the herb season (starting with cleavers, dandelion and witch hazel, right soon now…) and thought it might be worth a repeat!
For me, the most fascinating part of my whole self-sufficiency project is the plants – don’t get me wrong, I love the skills, I love animals, but I think I like best the project of getting to know plants. The joy of herbalism is that it requires an intimacy that I really delight in – the more I learn, the better the results, and the more pleasure I take from my garden plants.
When I first started planting culinary and medicinal herbs, I pretty much treated them all the same way – when I wanted some, or when it was a convenient time for me, I went and cut what I wanted. But gradually I’ve learned a lot more about harvesting – when and how, and how to make best use of the plants. Some of this is most important if, like me, you are hoping to sell dried herb, but harvesting at the right time will make anyone’s plants more medicinally active – we all know that there’s a world of taste difference between a green tomato and a red, ripe one dripping from the vine, between a tender, delicate new 6 inch zucchini and a three foot, seedy monster. Well, herbs also have windows in which they are at their best.
Still, there’s something to be said for the “just go out and pick the herb” strategy – and for most fresh uses, I think this is probably still a good one. There will be times when you want the most chemically active possible plant, but if your kid has an upset tummy and you have a dill head lying around, there’s really no reason to spend a lot of time wondering if you should have picked it on Friday or should wait until the seeds are fully mature. By all means, try and harvest at the best possible moment, but don’t make yourself nuts, unless you are trying to sell your herbs.
There’s no real rule of thumb that allows you to completely avoid getting to know the plants themselves more intimately (and after all, this isn’t really something to be avoided), but there are some general principles that can be applied usefully. Generally speaking, if what you harvest is the flower (say, chamomile or red clover) you want to harvest it just as the flowers open, as close to opening as possible (being pollinated can reduce the medicinal qualities of the flower, as in the case of clover).
If what you harvest is “aerial parts” (say, as in scullcap or feverfew) then you generally (there are some important exceptions to this) want to harvest the top foliage and flowers just as the flowers open. If what you harvest are the young leaves (like nettle or raspberry leaves), harvest in spring, or keep cutting back or succession planting to ensure a harvest of young leaves. Seeds (such as milk thistle and burdock) are harvested when the seeds are ripe, that is fully dry. Berries and fruits (such as cayenne peppers or elderberries) are harvested when ripe, or just shy of ripe. Roots (such as dandelion or echinacea) are best harvested in fall after die back, or in very early spring, before heavy growth is put on.
Barks, (like willow or crampbark) are a winter crop - and in fact, I wonder that more northern farmers don’t consider adding a few bark crops to add to their other winter work with wood – cutting firewood, pruning, etc…
There are some oddities among the herbs – Gingko leaves, for example, are harvested not when young, but when they begin to yellow. Comfrey is gentler and safer after the first spring flush – the first crop can be cut for compost or animal feed. Rosemary is more fragrant and active after flowering, rather than during it. Some roots need several years to develop, others are at their best the first fall or winter. Again, you’ll want to look at recommendations from several books, since people’s opinions vary a lot on this stuff.
What if you want to combine two herbs with different harvesting periods in, say, a tincture? You have two choices – you can harvest both plants as close to optimally as possible, say, picking the late flowering clover and digging the burdock before frost to create a clover-burdock root combination, or you can double tincture – tincture the clover at its peak, strain, and then fill the jar again with burdock root, and tincture it again.
The two easiest methods of preserving herbs are folk-style tincturing and drying, and that’s all I’m going to talk about in this particular post. Again, the books you use will have recommendations for how to handle these plants – and I’ll write future posts about creams and oils and other methods. But for today, we’ll assume you are going to either tincture the herbs or dry them. You should look to see how the plant works best – as all of us know from culinary herbs, some herbs dry beautifully, some lose their essence. The same is true of tincturing – I’ve heard herbalists say that alcoholic tinctures are the best way to preserve herbs flatly, but some plants have constituents that don’t precipitate out in alcohol – marshmallow, for example, is valuable mostly because of its mucilaginous qualities, but that mucilage is not alcohol soluble, so an alcohol tincture isn’t the best way to preserve it.
Tinctures involve preserving herbs in alcohol, vinegar or glycerin. Glycerin has the advantage of being sweet and easy to give to children, vinegar something everyone can tolerate, alcohol’s biggest advantage, besides pulling many plant elements out, is that tinctures last forever. That way, if you are trying to preserve an herb you can’t grow, or don’t expect to have access to forever, tinctures are really valuable.
Either way, take a quart mason jar, and chop the herb parts up finely (for particularly dry or encased parts, like woody roots or hard coated seeds, you may need to grind them up some in a mortar). Fill the jar to the top, and add alcohol (100 proof vodka is the easiest, although you can also make tinctures in fortified wine, or in a high proof alcohol that you enjoy sipping – no reason you can’t enjoy, say tequila-lemon balm or gin macerated with elderberries – for your health of course 
), glycerin or vinegar.
Put the tincture in a cool dark place and shake it daily for a month, or more. Strain through cheesecloth and press or squeeze out all liquid. That’s your tincture. Store in a cool, dark place, clearly labelled with both ingredients and with warnings if necessary. Glycerin tinctures store 1 year if made from at least 70 percent glycerine and kept very tightly capped (they suck water from the air otherwise), vinegars last 1-2 years at room temperature, alcohol tinctures last indefinitely.
Drying herbs is pretty simple – in a dry climate, you can hang them up in a warm, dry place with good air circulation and no exposure to sun, or lay them on screens and just let them dry until crispy. This method doesn’t work at all for me in my humid climate – plants keep absorbing humidity, and turn grey and dull. A solar dehydrator doesn’t work for this – bright sun is not good for most medicinals. So we turned our mudroom (which has a lot of windows and gets very warm in the summer into a drying room. A humid-climate solar dehydrator with a dark cover also works fine, as does an electric dehydrator if you’ve no other choice. Generally speaking, you want to dry your plants as quickly as possible – within 1-4 days, and at a temperature between 80 and 100 degrees. Once they are dry, place them whole into an airtight jar or crumble them if you prefer (they last longer as whole leaves), and put them away from light.
How do you decide whether to tincture or dry? For me, it is often a matter of aesthetic pleasure – any herb I enjoy drinking as tea, I might as well dry. What’s the point, say, of peppermint tincture, when peppermint tea is so delicious? On the other hand, valerian doesn’t taste that good anyway, so I might as well cover it in cheap vodka . Also, if you have kids, I find it a lot easier to get them to drink a cup of tea than to swallow anything alcoholic, so either that or glycerin is preferrable. Books will have good recommendations about whether to tincture or dry, and some of it may depend on what you want to use them for.
The three books I’d really recommend starting with are James Green’s _The Herbal Medicine-Maker’s Handbook_, Richo Cech’s _Making Plant Medicine_ and for those growing their own, Tammi Hartung’s _Growing 101 Herbs that Heal_. It should go without saying, btw, if you are not cultivating these herbs, but wildcrafting them, you are doing so completely ethically – not taking more than a fair share of any stand, encouraging them to expand their range, not harvesting endangered plants. Wildcrafting is best used for plants that are weedy anyway - St. Johns Wort, for example, is a real pest in my friend’s pasture, so we help her out - and me.
Happy harvesting!
Sharon