Small tractor and plow.

When I bought my house I wanted to start a garden and I hired a guy with a small tractor (bigger than a lawn tractor but not a field-sized behemoth) to come in and till it. If you found someone like that who also has a front loader, he could spread the compost at the same time. Whether you can rent something like that, I don't know. You'd need a hefty trailer to haul it on.

If you are using a tractor, then disk in the compost, turn with turn plow, then disk again. Disk harrow will cut 4-6 inches deep, a turn plow will cut 10-12 inches deep & put dirt clods up on top of soil. This is why you disk again to cut the dirt clods & break up any matter that is now on top.
Most places top soil is the top 6 inches or less, but I have worked fields that the dark rich soil did not lighten up until you cut below the 10 inches mark.

Plow and disc would be probably ideal, but most places the machine is very large for a residential lot. Mid-size tractor with a rotovator will be easier to find. Some landscaping outfits have roto attachments for the bobcat.

I would use a rear tine rototiller to work that compost into the top 4 to 6 inches of soil. Over time the Soil Food Web will work organic matter deeper for you, but most grases root in the top 6 inches so that makes it important to add organic matter to that depth.
Drainage might be of concern which indicates soil deeper needs some attention if that is needed.

Good info.

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??

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.

Here is a link that might be useful: Tips for tilling

Thanks, Lazygardens - that makes more sense, I was reading it wrong.

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?

OK, here is something I didn't think of - if we're talking spreading enough compost and amendments to be several inches thick over a half-acre...trying to do this with a couple shovels would probably kill a couple of overweight, not-so-young-anymore guys if we could even do it in a timely way.

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?

OK, here is something I didn't think of - if we're talking spreading enough compost and amendments to be several inches thick over a half-acre...trying to do this with a couple shovels would probably kill a couple of overweight, not-so-young-anymore guys if we could even do it in a timely way.

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?

A skid-steer, amd you would better with the smallest, could do it fairly quickly and well as you could drop a bucket load at the rear and back-drag it to spread it.

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.

For eons, probably, soil preparation was to plow and then disc and that was the accepted method. Many years ago many of us found that we could easily skip using the plow and just disc which mixed the organic matter into the top 6 inches, or so, of the soil and did not bury it 8 top 12 inches deep. Discing, rather then plowing and then discing, is being promoted today as an eco friendly method of soil preparation.
Plowing will simply bury your organic matter and is not something I would do today, although with the 4 foot wide beds I have there is no soil preparation necesary.

So even in a lawn that will have trees, is it necessary to have OM any deeper than 6-8" outside what will naturally work its way down there over time?

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?

Using a tiller produces a finer grade of particle which seems fine when planting but it also means that when it settles and it will it packs more tightly; therefore your garden/yard soil will pack harder even if one never walks on it.

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.

The numerous times I have been in a forest, woods, or other natural area and have dug down into the soil i have not found a significant amount of organic matter below about 6 inches, maybe 1 or 2 percent below that level. Below that 6 inch level most of the bacteria have appeared to be anaerobic while the aerobic bacteria are concentrated in the top 6 inches of soil. Earthworms have been found below 6 inches and quite active at lower depths. Many plants do send roots to considerable depth, but the majority are concentrated in that top 6 inch depth, where the Soil Food Web is most actively feeding them.

kimmsr made a good point- in the forests of Maine, Minn, and Texas (places i've dug), there is relatively shallow top soil covering deep clay of various types and colors. Trees send anchor roots deep and have feeder roots in the top 6-12". Same with grass, veg, flower, etc., the top 4-6" is the 'gold zone' to focus your composting and soil building efforts on.

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.

"The numerous times I have been in a forest, woods, or other natural area and have dug down into the soil i have not found a significant amount of organic matter below about 6 inches, maybe 1 or 2 percent below that level."

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

Lloyd

Using the same Simple Soil Tests I have posted here numerous times over the years, Lloyd.

I'm impressed that whilst walking through these natural areas anyone would A) take the time to do a soil test and B) be able to discern the OM content so accurately.

Lloyd

You might be able to find/rent a drum compost spreader that's made for jobs like big lawns.

{{gwi:298169}}

Some one makes and sells what are called estate size manure spreaders, but no matter to spread large amounts of compost over large areas a manure spreader would be something handy to have. If a nearby farm has one you might be able to rent it.
Lloyd, some of us go into the woods for reasons other than a casual stroll, like a biology, horticulture, soil science class assignment or maybe just plain curiosity.

Kimmsr, not revealing your sooper sekret methodologies is savvy! I took a soil class and had to go dig to various levels then scoop a specific amt of soil into a pint jar. Once back in the lab and water added, jar shaken, then analysis of clay, sand, humus, rock, etc., to show the changing makeup of soil at diff depths.

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.