Today I'm using a new tool . It's a tool that was developed by Eliot Coleman, one of my gardening gurus, and its purpose is to aerate the soil at a deeper level than normal tilling or surface cultivation allows. In his book, The Four Season Harvest, Eliot Coleman says that he doesn't dig his beds any more, but rather just cultivates them shallowly on the surface to remove weeds. The natural soil structure is preserved that way, and the soil drains more easily and retains humus and good crumb structure better. That is also my experience: there is no need to double dig your beds. In fact, doing so probably destroys more soil structure than it creates.
But when we grow mostly annual crops such as vegetables, the soil does not get deeply aerated by perennial roots. One way to fix that is to grow deeply-rooted perennial cover crops, such as alfalfa and clovers. But those crops are difficult to dig out by hand when you want to follow them with vegetables. The broadfork also accomplishes this deep aeration more conveniently sometimes.
It takes a while to get the knack of using the broadfork. Mine has five tines that are angled slightly to the front of the user. So the gardener has to tilt the handles of the broadfork slightly forward, in order to get the tines perpendicular to the ground so that she can step on the crossbar to force the tines into the soil. This can be a bit of a balancing act.
Once the tines are down in the soil, the gardener then gets off the cross bar and pulls the handles toward herself and then pushes them to ground if desired. This lifts the soil and exposes the clay subsoil to air.
The bed I was digging had perennial weeds in it, mostly asters. I debated whether to broadfork first and then remove the weeds, or remove the weeds with a little fork and then broadfork. The former course seemed to work better: the broadfork loosened the roots of the weeds, making it easier to remove them with the little fork. Of course, you could also till and then broadfork, or broadfork and then till.
Back in the eighties, I had what was called a U Bar digger, designed by John Jeavons. I had it fabricated at a metal shop in town, from John Jeavons's drawings. This was a huge, heavy thing that I could barely lift. Its tines were much longer, and often they wouldn't go all the way into the ground. The broadfork is a much more human-scaled tool, easy and pleasant for me to use.