One of our local gardening radio gurus recommends this

http://www.goldenacregarden.com/gguide/soil/zeolite.htm

I had the same trouble with my garden until I tried the zeolite. Last fall I added compost, peat moss and zeolite and in the spring, everything was nice and loose. My earth was so compact before the zeolite, I couldn't even grow any root vegetables. Good luck....Heather

Thank you so much for the link Ginger57. I saw zeolite at a Winnipeg garden centre and wondered what its purpose was. I'll have to give it a try. Hopefully I can purchase it locally.

It helps if you can avoid walking on the soil too. Since I built raised beds (and added manure), I have had very loose soil.

I would say my soil is clay too. My trick is to rake up all the leaves and mix them into the soil. In fall when I cut back most of my plants, I shred them and they go into the soil. I've noticed a great improvement in the soil. I've also heard that mixing in sand helps too.