Terracing on a steep slope in Appalachia

Hi all, I am planning to turn my property into a small food forest. It is about 1.5 acres in Eastern TN in Appalachia. Most of the property is a south facing slope of about 27 degrees. The southern boundary is next to a road. The top of the hill levels out near the northern boundary and I want to build a a house there eventually. I have plans to build a small tiny house on the side of the hill along with terraces. I was planning to start digging out a terrace near the bottom of the hill by hand, it would also create a space for vehicles to park along the road, and I need some help. I want to preserve the soil fertility and I've read that if I dig and mix up the soil layers then I will destroy the soil ecosystem. So the plan I have in mind is to collect the topsoil and seperate it by putting it in boxes. Then i will dig into the soil where I want to build the rock wall, place rocks down until a wall is formed a couple feet above grade, then move the remaining dirt from the front of the wall to the other side, creating a level terrace. Once this is done, I would replace the topsoil. Does this sound like a viable strategy? Do I need to seperate more layers of soil? Also, will terraces that are about 5 feet in depth and 2.5 feet high would be sufficient? Because the slope is about 27° and tan(27) roughly equals 1/2. On the terrace i would have about a 2 foot path for walking and 3 feet for planting. Would this be enough space for planting fruit trees? Those are some of my more pressing questions but I will probably think of more and post here. If there are any resources on terracing or threads that have answered these questions, please send them my way!

Hi C,
Specific to the soil mixing and killing ecology - just the act of that much disturbance will kill a lot of microbiology, just like tilling would. My personal approach is to till the first time to get the spot ready, and then try never to till again. In this case, I think removing the top soil and adding it back on would be a good idea. It might be overkill, but not a bad idea. If you did mix the topsoil and the next layer, but were practicing good soil health afterwords with amendments, microbiology, compost, mulch, etc. I think you would be fine with mixed soil. I do that sometimes on a small scale when I am putting a post in my garden and dig down 2 feet. My stuff still grows fine in the mixed soil and I can't even tell by looking, after a few weeks.

I do not have enough experience with fruit trees on slopes to speak definitively about whether that is too small. It seems like the terraces would be a bit small, but you can keep fruit trees small by pruning, so maybe?

I have done similarly here in Vermont, on a similar slope as well, although my paths are a lot more narrow. Originally I began similarly to the way you are describing. In sections I dug and weeded the topsoil, put it in a pile to the side, shaped the subsoil with my hoe, and put the topsoil back on, layering as I went with green cuttings, charcoal, sticks, and microbial inoculation via forest soil. It was a very nice bed and everything grew amazingly. That was the steepest part, and I think it worked out as well as it could have. But since it took so much work, and I have moved onto slopes a little less steep—more like 20 degrees—I am now digging contour trenches and depositing the soil uphill. Sometimes I’m turning them into hugelkultur. The thought is that behind the berm, the soil will grow with more and more organic matter, and there will be less soil disturbance. It’s less work too, and what work there is is more gradual. And it has worked well and sinks lots and lots of water into the soil, spurning much growth on the downhill side.

Right now they are covered in snow but it should melt soon, and I’ll take pictures.

I wish you luck with your gardening!

There is a balance between encouraging water to soak in and making sure that the "steep slope" stays safe. Planting trees goes a long way to stabilizing the new slope, but making sure that the terrace surfaces slope slightly down hill so that extra water drains, was something I remember from one of Sepp Holzer's books.  You might find that reading up about some of his techniques for terracing would be beneficial.

Jay Angler wrote:There is a balance between encouraging water to soak in and making sure that the "steep slope" stays safe. Planting trees goes a long way to stabilizing the new slope, but making sure that the terrace surfaces slope slightly down hill so that extra water drains, was something I remember from one of Sepp Holzer's books.  You might find that reading up about some of his techniques for terracing would be beneficial.

That’s true as far as I hear, though I haven’t experienced it. Grasses are also good for helping stop erosion. I have generally gone for maximum soaking and slanting it inward and there hasn’t even been a hint of mudslide; my soil tends to be a loamy topsoil and a fine sandy-loam subsoil, so maybe it’s better draining in its nature. It could also be some of the sticks layered in that are helping.

Edit: it’s kind of a smaller terrace, so it can drain excess water at the ends like one of those fish scale swales. Something longer might have more problems.

I was inspired by Sepp’s terracing. He also put plenty of ponds on the terraces. So I’m guessing it is a balance based on soil types, land, rain patterns, and vegetation.

Has anyone here had issues with mudslides? It would be good to hear about the conditions where it happens.

Maieshe Ljin wrote: Has anyone here had issues with mudslides? It would be good to hear about the conditions where it happens.

It is certainly a concern in the Wet Coast ecosystem, although not near me.

There are high risk signs in mountainous regions and one of them is looking at on-line close-ups of the areas nearby looking for the geological signs of mud/rock slides in the past.

I'm not sure which underlying rock formations are more or less prone to the problem, but I expect that info is available on geology sites. I have certainly read news reports "after the fact" stating an area was at high risk and homes shouldn't have been built there. That's way I'm suggesting people "do their homework"! I'm not trying to discourage an excellent option in the tool-box, I just like to keep my permies safe and alive!

There are whole hillsides in areas of Asia that have done this, so it can be done safely, and it's an awesome way to increase one's planting area. Many of those hillsides were terraced a very long time ago, and yet, often the people have an oral history tradition to teach how to build and maintain them.

I have only an  urban yard to work in, but I've terraced and re-terraced it, as the need has arose.
I usually drive stakes along the line that delineates the face of a terrace.
I then stack logs, branches,  lumber, etc, behind these stakes.
From there I move soil from upslope, to behind the logs/lumber etc, until the soil grade is roughly level with the top of the stakes or the terrace is deep enough,from face to face.
I often need to add longer stakes, to get a terrace that is deep enough.