JB:

I'm not a botanist, just an herbalist, but having grown a garden and herbs in Pennsylvania, I'd be glad to share what I know.

The thing that breaks-down clay is gypsum (calcium sulfate). I'm talking about a lot for the kind of clay soil in Pennsylvania. I think I had about a 4-6" layer on my garden and I tilled it in about 12" deep. I did this in the fall for the spring planting.

Here's a little chemistry: Garlic is a sulfur plant (lilliacae family). It loves sulfur. The gypsum served two purposes: It broke up the clay and it provided an abundance of sulfur to my garlic. My garlic grew 6 feet high.

Comfrey has lots of calcium. And it likes lots of water. So, see if gypsum is the thing you need . . . PLUS manure, of course. I'd make your initial bed about one to one & a half feet deep.

I use the root despite what some people say about it being a carcinogen. I'll be called irresponsible by saying this, but in the hands of well-trained herbologists, it's invaluable used in the right way.

theherbalist
charlie

They grow fine in heavy clay - that is exactly what I have here in Western NY State. I have amended garden beds but the soil there is still largely heavy clay.

Last year I started a new plant from a root piece I purposely cut off a parent plant for that reason. I gotta say that it took a "month of sundays" (ie a long time) to see leaves. The plant grew under the soil a long time before pushing leaves.

Just plant it. Keep the spot watered - as you water your other garden plants. And be patient. My new plant (planted in a non-garden location in my nearly solid clay soil) is happily blooming at the moment. Yours will too next year.

FataMorgana

Organic amendments are probably best for improving clay soil. Gypsum may or may not be helpful in breaking up clay; it can actually be detrimental.

Internal use of comfrey has been discouraged by many herbalists, not only because of risk of carcinogenicity, but due to potential severe liver damage.

"Scientists and medical doctors agree that the use of Comfrey should be restricted to topical use, and should never be ingested, as it contains dangerous amounts of hepatotoxic pyrrolizidine alkaloids (PAs). Use of comfrey can, because of these PAs, lead to veno-occlusive disease (VOD). VOD can in turn lead to liver failure, and comfrey has been implicated in at least one death. In 2001, the United States Food and Drug Administration issued a warning against internal usage of herbal products containing comfrey, and eventually banned Comfrey products intended for internal use. In addition to restrictions on oral use, scientists and medical professionals recommend applying Comfrey extracts no longer than 10 days in a row, and no more than 4-6 weeks a year."

Agreed on the organic matter. It is what I use in the garden beds to lighten up the soil. If you compost, use the finished compost in your gardens. It is black gold in the gardens and exactly what you need.

FataMorgana

Comfrey does well in clay soil, so you really don't have to change a thing.

On the topic of clay soil additives, the best thing to break up clay soil is sand. Soil class is basically determined by the ratio of clay to sand to silt. Organic matter added to clay soil will still be clay soil with added organic matter. What appears to be lightened or broken up soil is due to the soil being physically broken up, without the soil class having been altered at all. In time as the clay settles, the organic matter will just be swallowed up with the clay and will have no lasting influence as the clay compacts again.

Enjoy your new plant! Comfrey is a wonderful healer :)

"Organic matter builds soil tilth in a couple of ways. First, the organic matter coats soil particles, physically separating clay particles and aggregates from each other. Second, and more important, microorganisms that degrade organic matter produce byproducts called glomalin that bind individual clay particles together into aggregates. Particle aggregation in the topsoil reduces crusting, increases the rate of water infiltration, and reduces erosion and runoff."

See page 6 of the article linked to below, concerning hazards of attempting to amend clay soil with sand.

Here is a link that might be useful: Improving clay soil

The material in the linked in article is pretty much exactly what a person from a local Cooperative Extension taught regarding clay soils in a soil class I took a number of years ago. Compost and organic matter works in my gardens and I do have a very heavy clay soil.

FataMorgana

Sorry eric, unlike you I do not research articles online, and am not going to start now. I studied Horticulture in University (which included Soil Science) for 4 years and have been a professional Horticulturist working in my field for over 15 years in a region that is predominantly clay soil. There's a big difference between sharing what you have read online and actually speaking from long term extensive first hand experience. Have you personally worked with clay soil in hundreds of clients' gardens for 15 years?

I could reference thousands of articles that provide misinformation, especially regarding plants, herbalism and gardening. Articles promoting using peat moss in gardens, adding gravel to the bottoms of pots, adding bone meal to every planting hole are among my top peeves,with adding compost to alter a 'soil class' for a long term solution is among the middle ground.

Wyld:

One thing that catches my attention about you on your last post was . . . you're able to see outside the "normal" box. So, you MUST know what you're talking about.

Thanks for sharing your expertise.

Charlie
theherbalist

I've worked with clay soils all of my gardening life, from midwest clays to southern "gumbo" clay soils, and while there's no easy solution that works for everyone under all conditions, adding organic matter always is beneficial.

Neither my stated personal experience or WyldViolet's can be verified from forum postings, which is why articles referenced from reliable sources are valuable.

In my experience comfrey will tolerate a wide range of soil types but must have water to thrive, it does not like dryness for long.

The young leaves are the safest part (have the least PA's) but as an herbalist I know says 'the poison is in the dose'. The young leaves and root are both safe if used appropriately for limited amounts of time. Comfrey salve may be used daily with no problems.

Totally agree with you, Kaliaman. Actually, I don't know anything about PA's (a term conspired by modern technological gerus). But I only use it on short term situations anyhow. Quite safe that way.

I don't post all the time here, K. Are you new?

theherbalist
charlie

Yes the herbalist I am brand new to this forum. I am Kali from Texas and so far am enjoying the posts of several knowledgable herbies here. Hello!

Comfrey root has been found to contain 10 times the level of toxic alkaloids present in leaves.
A highly knowledgeable and respected herbalist, Varro Tyler (in "Herbs of Choice") has said that owing to its dubious effectiveness and toxicity, "comfrey has no place in our modern materia medica".

Here is a link that might be useful: comfrey toxicity

Comfrey root has a long history of very safe use.

It's good to know the biases inherent in your sources of information.

Varro Tyler had a reputation for being anti traditional herbalism...in other words he was biased against traditional uses of herbs. He was a scientist who only believed what he could prove in his lab, in other words his knowledge of herbs was purely intellectual...he was not an herbalist who actually worked with clients who were taking the herbs.

Medicinal plants are much much more than the sum of their chemical constituents....they are incredibly complex living organisms whose interactions in the human body cannot be completely understood just by knowing what their constituents are.

In addition, his writings have been reviewed, critiqued and some parts debunked by a host of other highly knowledgable and respected herbalists. Notably herbalist Jonathan Treasure has reviewed his writings in depth.

So while his research is certainly useful its not entirely authoritative.

Having said all that I believe comfrey root is safest used topically in salves and the tea of the young leaves used only when specifically indicated and for short periods of time.

Respectfully, Kali

If "traditional herbalism" means "accepting stories passed down over the years about herbs without bothering to investigate further", then Tyler certainly was not that.

Tyler said "true herbalism encompasses scientific testing, honest reporting of the results, and safe use of effective herbs by informed practitioners and the public". He was opposed to what he called "paraherbalism".

http://ezinearticles.com/?Four-Tests-to-Know-If-You-Believe-in-Para-Herbalism&id=2405530

In the foreword to his book "The Honest Herbal", Tyler quoted Frank Herbert:

"Beware of the truth, gentle Sister. Although much sought after, truth can be dangerous to the seeker. Myths and reassuring lies are much easier to find and believe. If you find a truth, even a temporary one, it can demand that you make painful changes."

Here is a link that might be useful: American Botanical Council recognizes Varro Tyler

Varro Tyler did some good work in his lab researching plant constituents, no question, believe I mentioned that in my original post. I am quite familiar with his work and idealogy. And he is recognized by all herbalists and herbal organizations, not just the ABC.

The ABC was founded by another plant constituent guy so there is a natural affinity there.

'True Herbalism' is a phrase Tyler coined in his attempt to disparage traditional herbalism. Traditional herbalism to me means in part, honoring the knowledge of plants and how they heal passed down through the ages by people who actually used the plants.

How wonderful to be living in a modern age where science supports traditional knowledge!

Your post proves my point Eric, thank you.

To each his/her own : )