|Even before I lived with a chef (my ex-boyfriend and current friend), I loved to cook and I used herbs in my cooking. An herb garden was a great idea for me because it gave me a continuous supply of herbs like thyme, oregano, and rosemary. In addition to those perennials, annuals like parsley, cilantro, and basil were great in the garden because I like to use them fresh in my cooking and because they are so dang expensive to buy.
But when I began gardening more seriously, I found recommendations to plant other herbs and flowers near my crops. For example, my "gardening bible" How to Grow More Vegetables by John Jeavons says to plant oregano here and there throughout the garden to improve the growth and flavor of your plants and to plant calendula, basil, borage, and bee balm within your tomatoes. Or at least I think it does because I'm reciting this from memory. (My copy of that book is quite dog-eared at this point.)
Some of these herbs and flowers improve the growth of your crops, some improve the soil, and some repel pests. Even some of the weeds are beneficial and should be allowed to grow among your crops within moderation. So I did this. And then I had a bunch of calendula and borage, etc, on hand and no idea what to do with it. Other gardeners who visited my house remarked on how much they loved these plants and how they used them medicinally. Huh, really? I was growing something valuable?
If any of this sounds like crazy hippie lore, there's actually a scientific basis behind it. The terms to know are allelochemicals and allelopathy - two words my spellcheck thinks don't exist (it suggests agrochemicals and telepathy as correct spellings). Plants do far more than we think to control the environment around them. They lure beneficial microorganisms to their roots, and they can even control the types and amounts of microorganisms they attract. They also put out chemicals that can influence the growth of other plants. These are called allelochemicals, and the effect they have on other plants is called allelopathy.
Here is one example: Some plants produce allelochemicals to suppress the growth of other plants. Amaranth will suppress beans, and squash can suppress weeds. But allelochemicals are not always harmful to neighboring plants - they can be helpful too. Why not harness our knowledge of them and use it in our gardens to give our plants a free, organic boost?
More recently, I've been dabbling in permaculture and I realized something else. Permaculture relies heavily on perennials and there are precious few perennial veggies. Rhubarb and asparagus are the two that come to mind. Fruit trees and vines are perennials, as are strawberries. But if one wishes to employ permaculture, then that means looking to herbs, flowers, and other plants (even bushes and trees) that serve a variety of purposes in the garden: feeding people, feeding wildlife, attracting pollinators, repelling pests, generating organic matter to break down as mulch, creating a beneficial environment for other crops, using water wisely, etc.
The book Gaia's Garden provides a fantastic list of plants that like a Mediterranean climate. This means that they can survive both very wet and very dry conditions. For me as a California gardener who lives in a Mediterranean climate this translates to: plants that are difficult to kill. Maybe it means the same for you even elsewhere in the world. When it's our long, hot, dry summer and I forget to water my rosemary, it doesn't mind. Neither do the cacti, but my poor little dragonfruit cactus drowned in a rainstorm last year while my rosemary soaked it up.
In my current house - the one I am leaving in a few days - we are situated near the top of a hill and our entire yard is on a slope. Gardening here means managing water and soil erosion. In our front yard, where we have no automatic irrigation or greywater set up, I employed these hard to kill plants around a swale (a permaculture term for a ditch that will catch water and allow it to seep into the soil). There, they can weather the long dry periods we get but also soak up the relatively (for us) huge amounts of water that will seep into the soil of my swale during the few rainstorms we get each year.
That brings me around to using the herbs indoors. For years, I've harvested my surplus herbs and hung them upside down to dry them indoors. (You can speed up the process with a dehydrator but I'm lazy and patient.) But then - what do I do with them?
Herbal medicine is something I approached with caution. Unlike pharmaceuticals, nobody is required to do double-blind studies proving that herbs are more effective than a placebo to solve medical ailments. But - that said - nobody will argue that some plants like aloe vera, eucalyptus, and marijuana are medically effective.
I've taken pharmaceuticals (for migraines) that had side effects of dry mouth, excessive yawning, vivid dreams, severe constipation, depression, nausea, making me sleep nearly 24 hours a day, and all kinds of trippy neurological side effects that made my body feel pretty weird. I always say that the second best thing a med can do to you is nothing, because side effects are miserable. For the most part, herbs are side effect free. So, you drink some ginger tea for your nausea and if it doesn't work, well, you're no worse off. Often herbs are pretty nutritious so perhaps that dandelion leaf didn't do what you'd hoped, but at least it packed a nutritional punch.
I say "for the most part herbs are side effect free" because there ARE some potent ones out there. Two herbs used for constipation are a great case in point: cascara sagrada and senna leaf. Overdose on those at your own risk. Even at lower doses, herbalists warn against using them unless it's truly a constipation emergency.
Also, because herbs haven't always been tested and they don't need to go through any sort of government approval process, there is often controversy over whether or not a particular herb is toxic. A great example is comfrey. In Kenya, Russian comfrey is eaten as a vegetable. Here, herbalists often caution against any internal use of comfrey, especially Russian comfrey, because it could be harmful to your liver. My own take away from various opinions for and against internal use of comfrey is: y'all figure it out and let me know - but in the meantime, I'm not going to drink any comfrey tea.
The flip side to this is that - again, because there's no expensive regulatory approval process - an herb that IS effective at curing or easing one medical ailment or another cannot be marketed as such. This is governed by the 1994 law known as DSHEA. Supplements and anything else that isn't a pharmaceutical but makes medical claims also carries the disclaimer "These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."
The claims you can legally make about herbs are vague statements about how they support or promote a specific body structure or function - i.e. supports respiratory health (not "Shortens the length and severity of a cold").
OK, so cautions and legal mumbo jumbo aside, herbs really can help with some medical ailments AND it's incredibly empowering to grow the cures to your own problems in your garden.
I'll also add that, while the placebo effect is "fake," it's not without value. Not that anyone would argue that accepted herbal remedies like aloe vera are a placebo effect, and no doubt many, many more herbal remedies are the real deal as well... BUT assuming that one DOES experience a placebo effect... hey, if it fixes your problem, why look a gift horse in the mouth? Unlike pharmaceuticals, herbs are cheap and - for the most part - healthy and safe.
When are they not safe? Well, if you're pregnant, taking prescription drugs, suffering from any sort of medical condition, or giving herbs to a child, it would definitely behoove you to do your homework first. And, as I noted before, some herbs are potent even in small quantities. But that said, I think this shows what it takes for someone to do serious harm to themselves with herbs (going back to the example of comfrey):
There are four cases involving humans which do implicate comfrey. One involved a woman who was finally diagnosed as having veno-occlusive disease & did consume a quart of herbal tea/per day that contained comfrey. A second case involved a boy with Crohns disease who was treated with conventional medicine for some time before going over to comfrey root & acupuncture. The long running malnutrition may have weaken the liver predisposing it to the venal obstruction problem. Comfrey root was blamed. The drugs were not considered as possibilities. The third case involves a woman who overdosed: 10 cups of comfrey tea a day & handsful of comfrey pills. After 9 years, she had serious liver problems. The fourth case became a fatality. A vegetarian, given to specific food binges for weeks, took an unknown amount of comfrey for flu like symptoms possibly over a period of four months. The particulars of his case are blurred. All cases involve comfrey; in at least three, there are suggestions of overdose or abuse of the plant.