He and I are looking to redo his lawn, and add 4 - 6" of compost or composted manure and tilling it into the clay. We want to go 12 - 18" deep to try and "create" a nice foot-plus deep topsoil.

What is a good type of tool to do this? The lots a bit too large for digging by hand, and a typical self-propelled tiller seems even a bit under powered for the half-acre lot. We don't want to overtill, just to a good, one-time work-in of some organic material, nice and deep, for a lawn with some trees and shrubbery as well.

What is a good, DEEP cultivator or tiller that can either attach to a tractor or riding mower that we could use and rent for a day or two?

I want to go six inches because eventually they want more than just grass - he does plan to plant some trees and shrubs, etc, that root far deeper than 6 inches. The existing ground is basically just subsoil. Kimmsr, drainage is a concern, although the lot does slope a bit, so if water got TOO excessive, I think it would run off into the street/storm sewer. That said, however, is another reason to go a bit deeper if possible.

Good to know it will eventually work deeper, however.

If I use the plow and disc method though, wouldn't plowing just bascially flip the entire layer of organic matter a foot deep to where the disc wouldn't reach it and mix it back into the existing soil? If you plow first, it would flip over the soil, burying the material deeper than the disc could turn back up, wouldn't it??

He said DISC first - that slices through the layers and mixes them up. Then plow, which turns up the subsoil onto the top. It's not going to completely reverse the layers. And finally, DISC again, which slices up the layers and does some more mixing.

You could do it with a fairly heavy rear-tined roto-tiller.

Make multiple passes, going multiple directions, and don't try to till to the full depth of the tines on the first pass. Get the top 6-8 inches well-tilled, then spread the organic material and till again, going deeper.

I guess I shouldn't try to post/read while at work...haha.

A side question - since doing this would destroy any mycorrhizal fungi present, would a light dressing of one of the commercially available mycorrhizal products be of any real benefit, or will they show back up, assuming I keep the OM levels up and don't re-till (which, in a lawn, is unlikely) after that?

Are there large spreaders that can spread at the kind of capacity we'd need or are we stuck hauling shovelfuls 200 feet from a huge pile?

Are there large spreaders that can spread at the kind of capacity we'd need or are we stuck hauling shovelfuls 200 feet from a huge pile?

One with tracks would cause less compacting.

After you are done discing one more time would be a very, very good idea and then water the hell out of it.

I have to imagine that in natural forests, you have a layer of humus-rich topsoil for sure, but that tree roots go well into the subsoil on their own as it is, right??

The main concern for me going much deeper is compaction - how to we find out if there is a "hardpan" layer or any compaction, and, if there is, how do we fix it?

Would there be any benefit of running through with a subsoiler first (before any amendments are added) then discing in the amendments? My thought is that it would break up any potential compaction down deep.

And - is there a big difference between only discing vs. just using a large tractor tiller? They go about the same depth, right?

Many people keep saying you never have to go deeper than x inches which means x inches of soil is worked and worked and worked and worked and worked till it is devoid of any natural material it once had.
My gardens, combined, are only approx. fifty by sixty feet plus or minus but I usually every year dig at least one, more often two, holes approx. four by four, plus or minus at least sixteen inches deep and bury plant debri plus kitchen wastes and what ever I have in those holes to keep the sub-soil as rich as possible.
The soil that was in the bottom of these holes also becomes the new top soil.

Of late I have been shallow planting my potatoes but when I deep plant they are a minimum of eight inches deep and I do not want them sitting on pathetic sub-soil.

No matter what some may say, especially those who use raised gardens and do not deal with the natural soil, rippers or sub-soil machines were developed for a reason. If you can get richer sub-soil, DO it, you only gain, you will lose nothing.

Do not forget some trees have deep tap roots and the entire root area of others is very shallow which can be seen when they blow over.

In the future, if there will be veg gardens or perm flower borders read about 'double digging', also mentioned in an earlier post. Lastly, i use a rear tine troy bilt horse to manage a 1/4 acre garden but what you're doing really needs topsoil/compost and disc that several others have described.
Good luck and have fun.

Pray tell, how did you analyze the soil to determine these numbers?

Lloyd

Lloyd

Not everyone does that type of thing while perambulating thru the forests and meadows but a few do, and this 'dirt aficionado' enjoys learning about that weird stuff.