Horsetail invasion - what does it tell me about the soil and what to do?

I'm invaded by horsetail. I know its useful but I'd like to grow other things too! What to do?

I remember pulling that forever in my moms garden as a boy.
What i know about it is a terrible thing to get rid of.
Mow it continuously, shade it out by planting shrubs, cover it in carton, grow things in big pots for now.
I don't know what your situation is, so it's hard to give advice.
Do you have 20 acres, a hectare, a medium size garden a small garden? Is it a problem all over the neighborhood? How long has it been there?How is your soil, compacted or loose? Does it regularly flood? Do you want to grow a food forest, a veggie patch ,a lawn, or just some herbs?

All really good questions.

Horsetail is typically high in silica, so much so in fact that the german for the plant translates to tin-plant, after the practice of using the harsh abrasive properties of the silica crystals on the ends of the leaves to scrub out mess tins.

Silica is often lacking as a garden micronutrient, so chopping and dropping into your garden or compost could be a good idea, although they will spread from the rhizome, so chop, don't pull.

In terms of eradication, you could eat all the young shoots next spring, if it's one of the edible varieties, and lime the soil very locally to the area. They prefer acidic soils, so they will not grow if it's too alkaline. I would try matching the preferred pH of alfalfa and overseed with that.

In lieu of lime, you could chop everything and overseed with a quick-growing green manure like buckwheat, and a nitrogen fixer, as apparently buckwheat has the ability to cause nitrogen-fixing bacteria hosts to overproduce, to satisfy the needs of the buckwheat. If going this route, I would keep an eye out for shoots and again, if they're palatable for you, eat them when they're young.

What it could mean, other than you have slightly acidic soil, is a great question. Perhaps Dr. Redhawk will be by to answer that for us.

-CK

Oh, and upon some further searching, it appears that buckwheat is a nitrogen-fixing bacteria host, but if I was planting a horsetail-smothering guild, I think I would build in redundancies, as in two nitrogen-fixing bacteria hosts, two fast-growing plants that provide cover, etc...

I was also thinking that, to keep it from spreading, a blockade of comfrey might work. I would just plant them on the perimeter, and chop and drop regularly. The root zone should contain the horsetail rhizomes, and keep them from any further advance.

-CK

Black plastic mulch and 3 hot summer months.  Gone.

Chris and others have covered the conventional methods.

Horsetails like to have constant moisture, so they have deep penetrating root systems to provide that water.
As has been mentioned they are silica plants and using them as a chop and drop is great for soil, do be sure to dry them well before laying them on the soil, I've seen fresh cut stems sprout new plants when just laying on the surface.

instead of using black plastic to eradicate, try a lasagna mulch of cardboard and several layers of mulch on top of that. Be sure the cardboard extends at least a foot or two out side the furthest out plant stem.

I have a ton of this stuff, black plastic does work but takes over a year in my climate, it will also run a good 6 foot under the plastic from the edges. It will come up through an entire straw bale   (I made a duck house from bales so they were down for several months)
It basically means you have a drainage issue, dry out the area and other plants will out compete, in nice damp shade it out competes everything I have except ground elder. Out of the two I'm not sure which is worse.

My observations — at least, what I've observed that I find most interesting — are based on our experience in our greenhouse, over the last nine years.  We built raised beds with no plastic or other barrier between the soil at grade and the enriched organic soil above that, in the raised beds.  There was horsetail in that area prior to when we erected the greenhouse and built the beds.  As people have said, horsetail is extremely persistent, tough and deeply rooted.  Wherever it is growing on the main bench where we have our house, outbuildings, and main cultivation, it is growing and rooted in a deep sandy-silty soil.

The topsoil on our place has been built (organically) over a period of about 60 years, by previous residents here and by ourselves.  Due to the raised-bed approach in the greenhouse, the organically rich soil we've built there is the deepest among all our cultivated areas.  Constituents of this soil include natural sedge-peat soil, rotted manures, decayed mulch (grasses like wheat straw, hay, mowed bunch grass, etc), and powdered volcanic rock.  Each year it's been irrigated deeply from early April through November.  It tests only slightly acid — like about pH 6.5.  None of these conditions, which seem to be perfect for raising tomatoes, cucumbers, hot peppers, and parsley, have discouraged the horsetail.  Given how well plants do in our beds, I can't view the horsetail as an indicator of any bad condition of the upper soil layers, though our deeper soil layers are admittedly sandy.

Although horsetail is not growing very thickly in our greenhouse beds, we do chop and drop what shows up there.  It seems to show up at about the rate it does in our outdoor garden areas.  I'm sure that the sandy subsoil under the beds does provide a silicon-rich environment for the roots of the horsetail, so I suppose that letting the horsetail decay into the bed soil is a contribution in that way. We don't tend to see the horsetail as a real problem.

Horsetail tends to grow in soil that is very low in calcium.  Don't really mind it in general-makes a good tea, and a girlfriend who had never seen it before commented that it was the prettiest fern she had ever seen.  Gave it new life for me. But I had it overtaking my garden and amended with oyster shell- it is very cheap bought in bulk for chickens - and also added all my egg shells for a year. did not have a single one come up in the garden area last year.

If a lot of Horsetail is growing in a garden, that would imply to me that the cultivation practices and the garden's propagules-bank favor Horsetail over other types of plants. Disrupt the Horsetail more, and grow more of other things, and the balance will shift to other species. (Which might be harder or easier to deal with than Horsetail.)

Joseph Lofthouse wrote:
If a lot of Horsetail is growing in a garden, that would imply to me that the cultivation practices and the garden's propagules-bank favor Horsetail over other types of plants. Disrupt the Horsetail more, and grow more of other things, and the balance will shift to other species. (Which might be harder or easier to deal with than Horsetail.)

Joseph, bottom land in my valley mostly has been owned and passed down in families who have been here since 60-90 years ago, a period of local settlement and land clearing for fields & pastures. And those of us who arrived during the last, say, 40 years have wound up acquiring upland (mountain-toe benches).  There's usually a lot of sand & gravel subsoil under a thin top layer in this bench land.  From my experience and the experience of a lot of gardeners I know, horsetail (being very deeply rooted) mainly depends on the subsoil.  When horsetail is present, it doesn't seem to matter much what we do in terms of upper-soil-horizon nurturing.  I'm not sure, but I'd guess that a sandy subsoil is just plain ideal for horsetail.