Amended clay can be great garden soil, but you mentioned being ready for next year. In that case, if it were my choice, I'd go for raised beds. Lay cardboard over the lawn to kill the grass, then put down cedar box frames with hardware cloth tacked on the bottom. Fill the boxes with good soil - compost, regular soil, some peat, etc., and you should be ready to plant right away - no waiting for the amended clay to settle in.

Just my 2 c's.

Bejay

Bejay,
What suits your needs most? Especially financially. The raised beds can sometimes come with a cost (cedar is expensive!!!) - you can make raised beds out of so much: old logs, bricks, cement blocks, untreated yellow pine (although I'm not sure how that would winter for you)...
Or if you till you can just get compost and till it all in. I do recommend compost and not just top soil. The compost is really great for soil structure building. If you can do this now then you still have time to cover crop, till that under, straw it and have SUPER awesome soil in the spring. This is the common preparation method of our local urban farmers who use a sustainable, organic, soil building method of land stewardship. Fosters a great soil food web!!!

If you go for amending, 1) you will have trouble tilling, because of the rocks, 2) you will get grass from the paths into your growing areas, and runoff topsoil (and seedlings) in the paths after heavy rains (is your area 100% flat by the way?), 3) long term amendments (and mulches) will increase the level of the growing areas so that, ten years down the line, you will get raised beds without an edge. Since you have heavy clay, if you choose to rotate the growing areas, you may consider the effect of compacting the soil.

So as you can see I am pro beds. A hard edge (I prefer cinder blocks) serves a number of purposes. I am also a heavy mulcher, and I now have experience with the difficulty of starting seeds in hard clay, and the only way out is to build one or two inches of friable soil on top. In a small garden you may buy a bunch of squash and tomatoes at some garden center, but with the spread you will have you will be doing a lot of seeds.

Personally, I'd probably go the raised bed route, Admittedly, if you're determined to improve the soil and plant in it, you'll have to do the hard part and dig the rocks. You can amend pretty well by turning in some leaf mold or compost when you dig the rocks, and then planting cover crops, that would get you pretty good soil in a few years, but the real question is if it's worth the effort of digging the rocks. I've done that before, and pulled somewhere between 30 and 100 lbs of rocks out of a 6 x 20 bed. I doubt I'll be willing to do that again, myself.

As for raised beds, they don't have to be that expensive, and if you're not really going to get started till next year you have the time to collect your materials cheap.
Look up Lasagna gardening for a really easy, and relatively cheap way to build a raised bed.
The basic method is, stockpile all the stuff you would use to make compost and then fill your raised bed starting with a layer of wet cardboard or newspaper, right on top of the grass, no need for a bottom in your raised bed. Follow this with thin (2-3") layers of browns, greens, finished compost and/or peat. You can dust in some wood ash or bone meal as you go to bring in some for trace minerals as well. You can cover that with black plastic and let it cook for a few weeks, or even plant directly in to it. Really simple, and if you spent the time between now and then collecting materials, you could probably get away with very little investment.

Lasagna= voles galore, specially since you will be doing a lot of the amending in winter. I always keep the main pile of leaves away from the garden, so they concentrate under there.
Also, once the soil becomes soft, rocks will emerge on their own over time.

Thanks for the responses. It sounds like raised beds are the way to go in my situation. Cygn's comments on rocks really tipped the balance for me - having gone through this with my fruit trees, just from 22, 24" holes a couple of feet deep I have a rock wall a foot and a half high and 50 feet long at the base of my orchard. That was not fun and I imagine it would be 10x worse trying to clear out a whole garden bed.

Answers to questions -

This is on an incline. It is approximately 8' rise over a 60' run. Because it's fairly steep I know drainage is important and had planned to dig a swale across the top of the garden to divert rainwater around the sides. I will install coarse sand on the border for anti-slug purposes, drainage and to make mowing around the garden easier. If that doesn't work I'll dig down and put in drainage pipes, but that's some hard work in the clay I have and I'd rather not.

Great advice on the cardboard strategy and vole avoidance for raised beds. I think the advice for hardware cloth on the bottom was to avoid voles which are plentiful here.

Appreciate the feedback and feeling good about having a definite direction forward.

You have already gotten some great advice. I would add that if you plant Alfalfa it would improve your soil in several ways. 1. It will break up the clay with it's roots ( especially if you leave it growing for 2 ~ 3 seasons ) 2. It will add organic matter when you cut and mulch with it. 3. It adds nutrients to the soil with its roots. 4. it controls weeds somewhat, once it's established.

In 3 years when you turn your soil or go to plant you may find ( as Glib mentioned ) that many of the rocks work themselves to the surface and are easier to remove. You said you have 2 acres and you are planning on a 1800 SF garden, you should have enough room to do some of your area this way, if you wanted. ( wish I had 2 acres :-)

GL

Hi FarmerBen... Although raised beds can be great and there's a lot of good advice above, there are negatives with raised beds. I started off with them but in the last couple of years I've changed to two large standard beds. My soil is full of clay (so much so I've built a clay lined pond) but with Autumn digging to let the Winter frost do it's work and plenty of self composted material it's very productive.

Click the link below for more extensive info on the disadvantages of raised beds. Hope it helps, Joh

Here is a link that might be useful: Allotment Heaven : Raised bed disadvantages

Good luck with your garden. Either way you go make sure you post some pictures for us to see!

Happy Gardening,
-Kristina K.

Here is a link that might be useful: Urban Farm Wife

IMO, raised beds. That's what I have & I also have hard, stoney clay ground.

My raised beds are filled with 1/3 clay...1/3 sand...1/3 turkey poo. A local farmer mixes it & hauls it. Maybe, you can check around for a farmer?