The herb list I belong to has chatted about "Lasagna Gardening" in the past, and I've always thought it sounded like a great concept. The idea is to layer four to six inches of compost or layers of material over a spot where you want to make a new garden bed. If the area is in your lawn, the layers will kill off the grass and the bed will be ready for planting without having to use harsh chemicals.
Oddly, I found a note about this method in the "Real Simple" magazine, November, 2003. They suggest mowing an area you wish to dedicate as a bed next spring, and then putting down four sheets of newspaper, and a four inch layer of shredded fall leaves or bark mulch. Hose it down and let it sit for the winter.
I think I may try this on a section of my formal garden that has been infested with grass. I plan to put down layers of newspaper, chopped leaves, shredded paper from the office, compost and grass clippings. What better time to renovate a bed than in the winter, when nothing is going on?
If you're interested in this technique, you can read more about it in " Lasagna Gardening: A New Layering System for Bountiful Gardens: No Digging, No Tilling, No Weeding, No Kidding!" by Patricia Lanza, et al You can buy the paperback new for $11.17 at Amazon.com. What have you got to loose?
I have a friend who is dubious about this technique because he believes that you need to "double dig" the bed to prepare it for use. With this technique, you mark off an area and dig a narrow rectangle of material as deep as 24 inches at one end. The material you take out goes into a wheelbarrow. Then you make a similar slice right next to it, putting the dirt that you dig out in the space created by the first hole. You keep working your way down the bed a spade width at a time until you get to the end. Then, you put the dirt you've been holding in the wheelbarrow into that last hole. It seems to me that you would need a spacer of some kind to keep the dirt from falling into the hole you are creating, but that's a minor problem. A bigger problem is moving all the clay to the top and my good topsoil to the bottom. You have to be a patient person to do this sort of preparation. AND you have to have a good source of compost to add to the mix to make the soil on top healthy enough to support good perennial growth.
I think both methods are worth trying. I just need to have a live in gardener, and Dear Husband says it's not likely to be him.