Double digging, Tool-Time style! Nothin' quite like a 200 horsepower tiller...

Yeah my first thought was also "double-digging". Tried and true method of making a garden bed when one has actual soil and not just rocks to work with. Tho normally it's back-breaking. He will likely be sinking in up to his knees for years.

Dave

worked for him because he had sandy silt and clay to mix. It would not do much for my clay on top of identical clay.

I wish! Cement-like clay here with only a 2 week window fall and spring to dig or till! Then it's either muck or cement! Nancy

Nancyjane. I have natural clay loam soil. Just west of me is silt loam which works up more easily.

What I did to make a mellow soil, and it is beautiful in looseness and absorbs water like a sponge, was to add 3 inches of medium, coarse, and coarser sand: 4 inches of local sphagnum peat moss: and other organic matter like leaf compost and rotted horse manure with lots of hay in it. I mixed these all together with the top 7 inches of my good top soil....beautiful in all seasons and workable nearly any day in the growing season.

I got called into work yesterday, so I didn't get to see the posts until just now!

I'm kinda thinking I might try it too! I have a backhoe/loader, its old but works good!

My soil is similar to his. I also have some deeper sandy/silt soil at the back of my pasture that I could move there. I have been digging a small pond there, as time allows.

I don't get much time due to my job lately. I'm an electrician in maintenance and there have been too many emergencies.

Visibly It goes down about 3 feet, But the 8' deep hole that I have dug won't hold water more than a few hours. Part of my land slopes to that side so the runoff builds it up.

If I move it up to the garden, I don't know what would be the best way to mix it in without breaking my back!

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Wayne, I need raised beds anyway, due to gophers, so I filled each of them with soil from different places. I mix in my own compost each year and all is fine.
It would be really nice to just dig up a garden area and have everything be hunky dory! Then I could do things like grow for the food pantry and the seed exchange!
Getting too old for the extra work nowdays, though, so I think I'll just stick with what I have! Nancy

The fix for him is drainage. When you have decent soil on top of clay, you get ponding of water at the base, and root rot. Doing a deep dig ONCE, and doing a backfill at depth with compost/organic mix, and some sand as well, makes for a base that will work for a decade or more. Or at least just mix the top layer into the clay layer. The quicksand effect will subside as the base layer naturally compresses.

My major concern with using the backhoe for double digging would be soil compaction. The soil would need to be in "working condition " the whole 3 feet down. Also the soil type would make a big difference in the success of this method. What works on my loam silt soils is a subsoiler working about 14-18 inches down. I have used a single blade on a 3point hitch behind an 8N ford working a bout 3' apart then working across the first pass. It will breakup any hardpan from using a tiller. and allow deeper root growth. follow this with a cover crop of rye and tillage radishes and you have hardpan and compaction problems undercontrol.

I would be very careful about bringing up dense subsoil clay. If you do, you will regret it. If the clay smells like methane when you disturb it, you should leave it alone. Or truck it off the property.

My rule of thumb: if your soil is heavy but supports a nice crop of grass and weeds, it can be turned into good garden soil. I'm encouraged to read some positive comments about sand for a change. I've been using sand to improve clay loam for over four decades, and it works great and is permanent. I start out with about 1.5 inches of sand spread over the soil and tilled in. If the soil is still dense and cracks when it dries, add more sand. I also add doug fir bark and dolomite lime. It's all good for soil structure. I grow some very difficult rare plants in this stuff with great success.

After I've tilled all this stuff in, I rake the soil into raised beds about 2.5 feet wide. I don't bother with a support structure, but that's a personal choice. This gives me close to a foot of sandy loam topsoil. And good access for weeding, etc.

My method applies to wet continental climates like New Jersey and the Pacific Northwest. I don't know how it would work in other areas, like desert soils for example.

I'm all for deep zone tillage but not for the backhoe method. Topsoil should be maintained at all cost. Whenever I dig up a tree stump with my backhoe I gasp at the subsoil that has been raised to the surface.

There are many equipment designs for breaking up the hardpan. I even purchased a chissel plow a year ago and like the results (except for more rocks). I just can't imagine anyone having experience with backhoes recommending them for garden tillage.

lilydude, You make some sense. Working in small amounts of subsoil may bring up some good minerals, but TOO much will hurt most soils.

I like your approach of using some sand. In the past it seemed that many would think or say, "You don't need that."...or that you had to get a very special sharp sand. I have found sand very useful here WHEN mixed with other amendments and then fully intragated into good top soil. Of course not all soils are heavier loams and need sand.

I have found sphagnum peat moss very helpful in loosening the soil. Again, it used to be condemned here..."Not renewable or sustainable." I don't know of any other amendment that is more renewable than peat moss. I get it by the truckload from a local pit.

I too don't border up my beds. I make them from 7 to 18 feet wide and I WALK ON THEM....HORRORS.

Too much "good minerals" will hurt soils? That's a new one to me. Certainly if you plough up a lot of deep clay into your topsoil, you should add sand and organic matter to amend it, but that's a different issue, and not hard to accomplish. The advantage of doing the deep digging is that you've put some topsoil down where you used to have pure hardpan. You need to loosen that hardpan, whether it's 3-feet down, or intermixed with your topsoil.

But I'll say it again. It's about drainage. In fact, if you dug up the deep clay and replaced it with rocks, that would work well too. But that would be a lot harder.

You've got to be careful. There are some clays that you don't want in your topsoil. They are so stiff that air can't get into them. They create anaerobic conditions which leads to the methane odor. You can't break them up with a tiller. They are extremely unpleasant to deal with in the garden. They stick to your shoes and won't come off, even with a strong jet of water. Nothing will grow in them. If you've got that stuff, I recommend that you either truck it away or bury it with good topsoil. Why turn gardening into a miserable ordeal if there are other options? Most heavy topsoils that support plant life are clay loam, which already has some sand and silt in it to help break it up. Google "soil triangle".

Here's another factor to keep in mind. Most of the plant root activity occurs in the top few inches of soil. This is because roots need oxygen, and most of the oxygen is near the soil surface. From the link: "The majority of roots on most plants are however found relatively close to the surface where nutrient availability and aeration are more favourable for growth. Rooting depth may be physically restricted by rock or compacted soil close below the surface, or by anaerobic soil conditions."

So the benefit of deep digging may not justify the tremendous effort, and the risk of messing up your topsoil. Now for growing big trees, it might be a good idea, because they may root very deep, which helps them to resist wind and drought.

I like to dig around 1.5 feet deep if I can. Deeper than that, you might be running into diminishing returns.

If you have a high water table or drainage problem, you can't fix that with soil improvement. You have to install a drainage system. The way to find out is to dig a hole and see if it fills with water. Plant roots can't grow much below the level where the soil is saturated with water. Another thing that helps is raised beds.

Here is a link that might be useful: roots

"I would be very careful about bringing up dense subsoil clay. If you do, you will regret it. If the clay smells like methane when you disturb it, you should leave it alone. Or truck it off the property."

I appreciate your concern, but mine isn't that dense and doesn't smell like methane..... It breaks down freely as long as it is in the right stage of moisture content. Too dry, rock hard, too wet, stuck together.

Why would it smell like methane? To have methane wouldn't that mean that you have organic material trapped in the clay since methane is produced by organic material?

Truck it off???? Why?

Maybe it would be a good thing to free it up?

The methane would disperse and then the organic material would break down and maybe help the soil?

I'm sorry, I'm just not following your logic here. Or maybe I'm missing something?

"My major concern with using the backhoe for double digging would be soil compaction."

I understand what you are saying, but the soil that is being broken up with that type of double dig wouldn't get compacted by the tractor.

"I have used a single blade on a 3point hitch behind an 8N ford working a bout 3' apart then working across the first pass"

The way I'm looking at this is that the 8N is compacting with every pass where the backhoe is staying to the side, never crossing back over the broken up, loose ground.

I'm not trying to start an argument, Please, I am just not on the same page or missing something?

I've never seen clay that couldn't be loosened by addition of other material, but I'll take your word for it. If that's the case, then it seems that we're not talking about a Ditch-Witch, but a real backhoe, which could actually just haul that clay out and dispose of it entirely. If you have such awful dense clay under your topsoil, it won't be doing anyone any good, and drainage will be seriously impaired. If it's really anaerobic, you won't be getting any drainage through it.

Now, in such clays, the methane is getting produced by soil microbes, and such microbes sure won't necessarily loosen the soil as organic bulk would. Those microbes, and the methane they produce, won't hurt anything, so aside from the smell, they can be ignored.

lilydude, you were/was, I can't remember the proper word, writing a post at the same time as me, I'm slow!

I don't have a high water table. My garden is compacted by the 50+ years of my Dad and the previous owner using heavy tractors.

My soil and clay are different than your area's, most likely.

They community that I live in is called Greenpond. The rumor is that the green pond that the name came from was on my property.

I can't see how it could have been a pond because the drainage is very, very good.

"my soil and clay are different than your area's, most likely" I am sure my soil types here in central Illinois are very different than yours. Subsoiler or chisel plow works great here. digging down 3 feet and inverting the soil is something that would be a bad deal here. Tillage radishes in south Carolina would have a long enough growing season to reach down 24 inches or more.
But you own a backhoe so you could experiment a see how it goes. When I experiment I use a small portion of my garden and see how it goes. let us know how it works out

If I planned to move that much dirt I would bury logs,limbs, wood,leaves,cardboard and other material while I was at it. I'm sold on hugelkultur after reading about keyhole gardens in Africa. In addition to the obivous amendment,ongoing rotting and settling fractures the soil for years with similar effect as subsoil plowing or chiesiling.
In response to the notion that most roots are within a few inches of the surface,therefore soil below 6 inches is of no benifit. Most is not all and those roots extending deeper are nessary and important. Not only are the deep roots nessary for supplying moisture,surface soil pulls moisture from soil underlying it. It is this capillary action transfering moisture from several feet below that makes sub soils important. Where water go's,minerials go. It has been proven that if soil 5 feet deep is amended to increase moisture retention,plants on the surface benifit. We went through this "roots in top 6 inches" b.s. about a year ago. Unless somone can prove plants grow in a few inches of soil sitting on solid concrete with same amount of fertilizer and water as those in deeper soil,let's not go down that road again.

Most soil action takes place in the top few inches of soil. Where do wooden fence posts rot? They rot at soil level. Logs buried 4 feet deep may keep for 100 years.

Arid areas tend to not have a sharp division between top soil and subsoil like more humid areas have. In arid areas the roots go down deeply. In wetter areas the roots stay mostly in the top inches where the moisture, air, and prepared food is.

I like to subsoil with tillage radishes.

Most soil action takes place in the top few inches of soil. Where do wooden fence posts rot? They rot at soil level. Logs buried 4 feet deep may keep for 100 years.

Arid areas tend to not have a sharp division between top soil and subsoil like more humid areas have. In arid areas the roots go down deeply. In wetter areas the roots stay mostly in the top inches where the moisture, air, and prepared food is.

I like to subsoil with tillage radishes.

Klem, I built a hugelkultur bed, about 6'x15', in late summer as an experiment.

I will see how it does this spring.

without a doubt if you have the soil open one ought to pile on the wood as much as possible. so long as some wood is rotten, all of it will rot and turn into loam. the question is how deep for veggies ( for fruit trees, the deeper the better). IMHO, 4 ft is a good compromise, just at the limit of what most vegetables reach, and yet as sheltered as possible gainst moisture loss.

I had a lot of big rotting tree limbs, I put them in the hole.

I have a lot of large dead oak trees, due to the drought a few years ago, I think.

I could probably hugelkultur my whole 3/4 acre garden!

The only problem is cutting some of them down, I'm afraid a limb will snap and come down on me.

I have about 6 or 7 on the ground, that's enough to do a big spot.

"You've got to be careful. There are some clays that you don't want in your topsoil. They are so stiff that air can't get into them. They create anaerobic conditions which leads to the methane odor. You can't break them up with a tiller. They are extremely unpleasant to deal with in the garden. They stick to your shoes and won't come off, even with a strong jet of water. Nothing will grow in them. If you've got that stuff, I recommend that you either truck it away or bury it with good topsoil"

If I had clay that dense, I'd just build a kiln outdoors, and make my own terra-cotta planters. When life deals you lemons... ;-)

But on a more serious note... I've gardened in sites where heavy clay was close to the surface. While it was hard to work initially, the clumps of clay would weather & fall apart when brought to the surface. I added gypsum and plenty of organic matter to keep the soil loose, and after several years, it was easily worked.

My home gardens are heavy soil with fairly poor drainage, and I'm in the process of adding sand to remedy that. It's slow going though; it takes a lot of sand - several tons - to treat 1500 square feet.

zeedman, I used 3 inches of mixed sizes of sand...mixed with 4 inches of local peat moss [90% sphagnum]. This was all mixed into the top 7 inches of topsoil.

My county soil survey says that in my area it is mostly Blount, Pewamo, and with tads of Morley, Brookston, and Crosby. Most of these soils are productive but slow draining. They are silt loams with silty clay loam in the lower and darker soils. I probably have Pewamo and maybe Brookston in the lower ends of 2 gardens. These are great soils if drained and even better when 'lightened'.

This post was edited by wayne_5 on Sat, Dec 27, 14 at 10:20

I can see dumping logs deep in the pit that the backhoe makes, but if you're going to be growing that season, keep those logs well under the topsoil that the plants are actually growing in. In my view, hugelcultur is a long-range proposition. In fact, after those logs have been down there for a few years, that's when to get the backhoe out and stir them up.

There is little sense in using a backhoe for routine (as in seasonal) tillage. But it may be the only way to develop the soil deeply in the long run.

That looks great!

I'm thinking of using a small rental backhoe to dig up my new garden the first time. The garden is between two rows of giant Norway Spruces. I picked an area where some blew over after the neighbor built a new house next door on a wooded lot. Between his excavating the roots of my trees and the additional wind load I get some more sun light. I have an age problem and a fatigue issue. I'm thinking the diggers on the backhoe bucket would be great to rip the roots up. I wouldn't actually dig with the backhoe.

John, I had a similar situation years ago. As soon as I started improving the soil, fertilizing, watering, etc, the tree roots moved in and completely took over. I had a compost pile near some trees that was full of roots within two years. Completely useless, I couldn't cut through it with my shovel. Maybe it would work if you keep cutting the roots around the perimeter. It depends on how deep they are.