Soil Building Question in Cincinnati

I'm a long time food gardener and I've recently moved to Cincinnati.  The soil here isn't soil at all, it's clay and hard to break even with a fork.  I'll be moving into a place in a month or so that allows me to do a bit of gardening so I'm wanting to get started on building some soil for the Spring.  Here's what I'm thinking, tell me what you think.

The area is about 300 square feet.  I plan on buying about 4 cubic yards of coarse sand laying it down and tilling it in.  I'll then apply about 4 cubic yards of mushroom and horse manure compost - both aged at least 3 years.  I'll work them in.  If my math is right that will be about 4 inches of each.  If I work both new layers into the top 4 or 5 inches of clay I should have about a foot of workable soil for next year.  In late November I'd also add a few inches of maple leaf litter ground up with the lawnmower.  If I go this route do you think I'll have some workable earth next Spring.

Honestly, I've never had build soil from clay.  It seems really daunting because of the amount of work involved.  All said and done it's not terribly expensive - it'll cost about $250 for the 300 square foot.  I'll start my own seed and factoring seed cost and electricity for the sprouts I'm out another $150.  So that breaks down to a bit over $1 per square foot.  I can certainly grow more than $1 worth of food per square foot.

Thanks for the forthcoming advice, it's appreciated.

Personally I would skip the sand.  Just adding lots of organic material is sufficient, in my opinion.  (My soil is clay also)

If you're worried about drainage you might want to use hugelkultur. 

I thought about that as there is huge quantity of yard waste that would be great for hugelkultur around here this time of year, but the landowner wouldn't care for that sort of land modification.  There is an area in the backyard that would be great for building a large hugelkultur bed, but it only receives about half a day of sunshine each day due to the shade of a massive, massive maple.

I did get the Ok to add 6-8 inches of material in parts of the backyard, though.  I was wondering about the sand because I thought it would be able to break up the clay quickly with a tiller.  I had thought of going a little lighter on the sand and heavier on the organics, but this clay is only a little better than hardpan.  It is so hard to even crack up with a pitch fork.

As a side note the composts I will use are predominately woody material, rotted horse manure, and mushroom litter.

I also would skip the sand:
cement + sand = concrete; clay + sand = adobe.

Compost is the best addition for clay.

I third skipping the sand.

You could make raised beds without digging (disturbing) the soil. Lay several thicknesses of damp newspaper and/or cardboard on the ground. If you have yard debris available, use a layer of that next. Top with compost. Then top with a mulch layer - straw or dried leaves. Wet everything thoroughly, and let sit over the winter. Come spring, pull the mulch aside and plant, digging through all layers as necessary. You might not even see any discrete layers, depending on conditions. Don't turn or till.

Start a worm bin now for your kitchen scraps. When spring comes, you'll have processed organic matter ready to go.

Consensus has it that I skip the sand, I'm definitely Ok with this.  I hadn't even considered that I'd be building adobe like conditions under the compost.  That could have lead to some headaches and some choice words. 

I rarely turn the soil, let alone till and I certainly value excellent soil quality.  I'm a firm believer that I don't actually grow plants.  I build up soil, assist in establishing a suitable environment for microbes and animals, and they grow the plants.  That said, I'd like to free up some of the nutes hanging out in the top couple of inches of the clay.  Now, normally I would lay deep sheet mulch instead of tilling in the fall so that by Spring time I have some pretty great dirt to play in, but with this stuff I'm just not certain that's the best idea. 

If I do end up tilling it, this will be the only time I do so and that's just to free up some nutes and create a transition layer between the "new" compost and the clay.  I've done this before with really sandy soil and had great results.  I'm also not worried about disturbing microfauna because it's virtually non-existent in this soil (yeah, it's really that bad - I'm pretty sure you could make pinch pots with this stuff).  I'm also planning on introducing earthworms to the bed once it's been built up. 

I'm totally new to clay though, so any advice you folks offer is definitely going to sit in my head for the next month or so until I have to make a decision.  I've been really spoiled these past few years in the Upper Peninsula - the soil is generally pretty sandy, but it's pretty easy to amend.  This clay nonsense is tough, but I love growing food so I have to figure it out.  Thanks to the folks who have chimed in so far.

Cheers,
Sean

I would also do a soil test and see where the ph is and whether it needs adjusting.  What is drainage like - are you on level ground or top or bottom of hill?  If it is poor you may have to consider improving it.  My clay is rock hard in summer such that my pickaxe makes little impression and I have to wait for rains to get anything done.  I added lots of compost with lots of worms and I believe the worms were very helpful.

A pH test would be a great idea.  I'll look into who offers those services in the area.  The clay is very hard.  Water runs right on top of it.  Half of the yard is the top of a hill, half is at the bottom.  I had planned on leveling the bottom a little and building beds partially on the built up area and partially on an elevated area.  I will have to be careful what plants I place where, but I have a good number of years of experience so I think I'll make some good decisions.

I had a friend dig me a trench about 2.5 feet deep, 10'wide and about 50'long in the fall.  I asked all the neighbors for their leaves (maples) I piled in all the sticks and trees that were lying around.  I put out a poster in the front for passersby to drop off their leaf bags.  The winter rains and snow watered it and first thing in the spring I covered it all up (with a tractor) with about 2' of dirt and put sand over top just to help with seed propagation.  (not mixed in).  My seeds took off and the huge sunflowers were practically self watered and all the food did well in the shade in the hot, dry August.  I had Spinach that was over a foot wide leaves.

I'll say skip the sand too... and encourage any earth shaping you can get away with to improve drainage and warm up soil in spring, and as much and as deep organic burial as you can stand.  Consider putting half the site in cover crops in spring like daikon radish or canola and clover, to prep ground for your fall crops if you do it that way in Cincinnati... nothing like LOTS of root action to break up clay.  Roots, roots, roots.  You are really counting on formation of organic reinforced crumbs to make your soil porous, and I have read that the sugars in raw decomposing organic matter (turned cover crop) make a big difference in formation of those structures.

Don't machine till if wet or dry.  Moisten soil and let come to moderate moisture for easiest working.

For more perennial gardens, one colleague swore by pounding quick rotting wood steaks in the ground to create vertical structure.

I would not count on sheet mulching for heavy clay unless you are using aggressive pioneer crops, and know that you are not going to have anaerobic conditions.