I dealt with similar soil several years ago, and I mixed in (also by hand) anything I could get my hands on: shredded newspaper, grass clippings, fabric shreds, cut-up yarn, old leaves, coffee grounds - anything that would decompose. Since I was getting it all down pretty far into the soil, I didn't have any random animal digging in the area. It wasn't immediate improvement, but I did see an improvement in the soil within a year. I have kept the area mulched since then, and the soil continues to improve.

If you have room in your yard you could look for local "free" resources to start a compost pile. Spent Coffee grounds, spent brewery grains, horse and cow manure, grass clipping, fall leaves, rotting wood chips. This is not a overnight fix this is something you would have to be patient and see to the finish. In the meantime you could focus on smaller raised beds or container gardening to brighten up your yard.

Soil that is moist is easier to till than soil that is dry or quite wet.

Compost is organic material and you need to add organic material to that soil so any vegetative waste, tree leaves, grass clippings, kitchen scraps, straw, spoiled hay. etc., that you can get and add will be of benefit. Compost does have the added advantage of having an active Soil Food Web already at work.

Perhaps these simple soil tests may help.

1) Soil test for organic
material. From that soil sample put enough of the rest to make a 4 inch level in
a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and
replace the lid, tightly. Shake the jar vigorously and then let it stand for 24
hours. Your soil will settle out according to soil particle size and weight.
For example, a good loam will have about 1-3/4 inch (about 45%) of sand on the
bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above
that, and about 1/4 inch (about 5%) of organic matter on the top.

2) Drainage. Dig a hole
1 foot square and 1 foot deep and fill that with water. After that water drains
away refill the hole with more water and time how long it takes that to drain
away. Anything less than 2 hours and your soil drains’ too quickly and needs
more organic matter to slow that drainage down. Anything over 6 hours and the
soil drains too slowly and needs lots of organic matter to speed it up.

3) Tilth. Take a handful
of your slightly damp soil and squeeze it tightly. When the pressure is
released the soil should hold together in that clump, but when poked with a
finger that clump should fall apart.

4) Smell. What does your
soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant
odor? The more organic matter in your soil the more active the soil bacteria
will be and the nicer your soil will smell, to a point. Too much organic matter
can be bad as well.

5) Life. How many
earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5,
according to the Natural Resources Conservation Service, indicates a soil that
is not healthy.

kimmq is kimmsr

You don't say where on this glorious planet you are located.

This project could take a year or more to see results. I prefer a no-till garden but you can certainly till if you want. Read up on raised beds and lasagna gardening which you may like.

You have nursery tables so maybe pots are the way to go until you get the soil the way you want it. Meanwhile start your very own compost pile and or worm bin.

Good Luck

Good advice on sheet composting and ideas for soil amendments. I don't have much to add except:

If you're in an area that desperate for organic matter, don't overlook urine as a nutrient source. There are threads here on it.

Juice bars and the grocery store produce department are some other ideas.

How big is this greenhouse?

I have a greenhouse which had a similar start soil. What I did was to build temporary raised beds from cinder blocks in the areas where I wanted to plant, and fill them with all the organic material I could find, making in effect large compost bins. After several years, the soil underneath was somewhat better. I put worms in the beds, and they thrived while the compost was being produced; after the compost matured, most of the worms left, but there are still a reasonable number in the soil.

My recommendation would be NOT to amend all of the soil, but leave the pathways you want to use alone. This way, your pathways will be more weed-free, and easier to maintain.

Renais

Second the shredded trees. I've got some of the most unyielding, compacted clay you can imagine, poisoned too. The stuff is so bad, digging through it with a mattock I hit a brick, and the only difference I noticed was that the material was a different color. I've broken several less sturdy tools on the stuff.

I tried lasagna gardening, but I had a couple of problems with it. My soil was not suitable for planting, I didn't have (nor could I afford) any finished compost, and I didn't have enough organic material (nor the right proportions) to get it to break down in the time available. Planting into the soil underneath, or planting directly into the sheet compost, just weren't options.

A tree trimmer stopped to deal with some overgrown limbs across the street from my house, and I asked them if they'll dump at residential areas for free (a lot of times they have to pay for dumping, so if they can find somewhere to unload that won't charge them, they're happy to do it). They agreed, did their work, and a week or two later they showed back up (they don't dump until the truck is completely full) with a few tons of assorted shredded wood and leaves. They admitted it wasn't great quality stuff, and I did have to pick a small amount of stray trash out of it, but I went and spread it out where I wanted to plant this year, 3-4 inches thick. This was in late autumn, and I didn't expect them to break down over the winter (they didn't), but I had heard good things about the water retention abilities of wood chips, and that covering the soil to insulate it and shelter living things would help. I watered a little bit, but mainly I waited for rain to capture in the chips.

It helped a lot. The clay is still tough and sticky, but holding the water on it where it couldn't run off has forced it to soften; I can push my fingers into it now (instead of buckling the steel of a hand tiller). Insulating it against freezing in the cold and baking in the sun, and having all that food and shelter for bugs, has invited many of them to move in: I'm overrun with isopods, millipedes and centipedes and palmetto bugs skitter around, I find the occasional grub or maggot (fine by me, they help break down animal poop when local critters stop by to donate), and worms are turning up both in my mulch and in the clay below it. I don't have as many worms as I want yet, but there are far more than there were, and if they live and thrive here, they'll breed here.

I didn't even dig for most of my seeds (though I could have if I wanted to), I just raked away the mulch, laid the seeds on the soil, and raked some of the mulch back (but less, I don't want it thick enough to kill my seedlings). The volunteer potatoes I found in my compost bin seem to love it, and the cucumber sprouts are going crazy. Between praying over my soil all the time, and doing everything I can to invite soil life back to do its own thing, I'm expecting a nice harvest this year.

One more thing: don't fret about the ants unless they're in your way while you're trying to plant or harvest. Ants can be your buddies in wrecked soil like that. I've found that they dig through this stone-hard clay with ease, they were most of what lived in my yard too last year. Don't hate them, appreciate them; why break your back digging air and drainage holes into that clay when you have thousands of tiny tractors willing to do it for you? Putting down a lot of organic material on top of your clay might attract them to move to those areas, that can actually help you a lot.

That's a great description of how mulch can help soil underneath!

"feral" soil.

excellent description

Great post biddenback and glad to hear of your progress so far. Please keep us posted. It really is a great example of how mulch can help.