Proper soil preparation is essential for success with annuals and perennials. Good surface drainage, percolation and aeration are the most important goals to achieve when preparing the soil for planting. Roots need air to function properly! The problem with clay soils is primarily poor aeration due to the lack of macropores (I bet you didn't know soil had pores) and poor percolation (water passing down through the soil). If the problem is exacerbated by poor drainage across the surface plants don't have much of a chance. Most perennials and annuals fail because of poor aeration. Perennials are particularly susceptible to root rot during the dormant period in winter when we get most of our rain and when the plants are not using water.
The only sure way to achieve these goals is to prepare a raised bed for your annuals and perennials.

How do I prepare a raised bed?

1. Site selection - Choose a location where water doesn't pool when it rains. (Away from downspouts, gutterless roofs and drainage swales.) Dig down about 12-15" deep to see if there is an underlying layer of clay or rock that prevents good percolation. If you are unsure: fill a hole with water and see if the water drains out in at least a few hours. If not choose another location for your bed.

2. Turn the soil - Turning the soil is the first step towards aerating the soil and improving percolation . Using a spade or tiller dig into the soil at least 6" deep, turning it over and breaking up clods as you go. Remove any rocks bigger than a golf ball.

3. Add amendments - Spread at least 3" of thoroughly composted organic matter over the surface of the bed. . This can be your own compost, decomposing leaves, commercially prepared compost or what we use exclusively and recommend , Complete Landscape Mix (CLM). CLM, contains: hen manure compost, worm castings (another form of compost), and Permatil, which is shale that is heated to 2000 degrees F., expands like popcorn creating micropores. These micropores permanenty improve your soil percolation. Straight permatil can also be added to your soil. Add limestone at a rate of 5 pounds per 100 sq. ft. Apply ESPOMA ORGANIC FERTILIZER at the rate recommended on the bag..Thoroughly mix the amendments with the existing soil using your tiller or spade. Through the processes of turning the soil and adding amendments you now have a bed that is at least 3" higher than it was when you started.

4. Rake it higher - Rake the amended soil from the edges to the bed to the center of the bed creating an inverted V- shaped pile of soil. Flatten or round the top of the pile, rake it smooth and you should have a beautiful raised bed at least 6" above the surrounding grade that is well aerated at least 12" deep, fertile and ready to plant.


© The Urban Gardener, Inc. 2005

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