In most cases, a new flower bed is established where there now is some lawn. Here are three approaches to digging the new flower bed.
The “No Dig” Garden” - This technique is best done in the late summer or early fall in preparation for starting the flower bed next spring. The benefit of this system is that you avoid having to do any sweaty digging to establish your flower bed. With this approach, you start off by outlining the area of the new flower bed with string and stakes. We are not going to dig up the lawn grass. Lay a layer of newspaper over the entire area of your new garden bed. The layer should be 5 to 10 pages of newspaper thick. As you lay the paper, have some dirt available to plop on top of the layers of paper to keep the wind from blowing them around. Now you want to wet the newspaper thoroughly. What you put on top of the newspaper is a function of what is available to you. You want some organic matter which could be chopped leaves from your own trees, Canadian sphagnum peat moss, straw, or hay. We want to put a layer of organic material that one to three inches thick depending on our material. An inch of peat moss is the same as three inches of straw. On top of the organic material we will put a layer of top soil two to four inches deep. Finally, on top of the top soil we will put another layer of organic matter to serve as a mulch to keep out weeds and keep in moisture. This can be chopped leaves, hay, or straw.
In a month or so, the lawn grass has died and the sod begins to decompose feeding earthworms and soil microbes. In two or three months, the newspaper has begun to break down, so when you begin planting flowers in the spring, you can easily dig down 6 to 12 inches. All that organic material is going to feed the soil creatures and the resulting soil a year later will be gorgeous. An easy technique that takes a little patience.
There are a number of approaches to hand digging. Our recommendation for the easiest system is to simply use a shovel or spade to dig down four to six inches under the sod and turn the sod upside down with the live grass facing down into the soil. On top of the chunks of sod you can put a layer organic material and then a layer of top soil. You can begin planting right away or let the bed settle for a month or two. If this job is done in the fall, you will have a good base for your flowers in the spring.
For folks in a hurry, you can rent a Roto Tilling machine that will break up that sod and make a nice fluffy bed of soil and organic matter that will be 4 to 5 inches deep. If we were doing it we would add a inch of Canadian sphagnum peat moss over the grass before beginning to till. This will insure a good level of organic matter in the soil for that first year. Let the soil rest and settle down a bit for a few days before you start planting.
Adding Organic Matter To Flower Bed
Notice that in all three techniques, we make a fuss about adding lots of organic material to the soil as you build your new flower bed. That is a very important step to having a healty soil in the years to come. However, that is not the end of the need for organic material. After your flowers are planted, you should always add a 2 to 3 inch layer of organic material such as chopped leaves or shredded bark as a mulch. This mulch should remain on the bed all year long. When it breaks down to about one inch thick, put another layer on. That organic matter in the mulch is the food supply for earthworms and soil microbes essential to your having a healthy garden.