While raised garden beds and tire tiers aren't new ideas, they are something you should look into. They are among the innovations that help gardeners overcome soils with too much clay or sand.

• Raised gardens are artificial layers of soil on top of problem soils. Make a frame out of treated 2-by-12-inch redwood or cedar boards. The length of the frame can vary, but keep the width to about 4 feet, so you can weed and cultivate the bed from either side without walking on it and compacting your new soil.

Sink the boards 1 or 2 inches below the level of the existing soil for stability and to contain watering. Anchor the frame with 2-by-4- or 1-by-4-inch stakes on the outside, to keep them out of the way of trowels, shovels and small rototillers. Use galvanized nails to avoid rust.

(If this seems like too much fuss, try the first season with a new bed piled up without the siding.)

Once you get your sideboards in, fill the bed to the top. Your new soil mix will generally contract about 2 inches, leaving a full 8 to 10 inches in depth.

Prepare the new bed by digging a full shovel deep into the old clay soil. Mix some of the new material into the clay so instead of two distinct types of soil there will be a mixed zone in between. The soil you add should be a mixture of top soil, compost and maybe some sphagnum peat moss.

Using a raised garden bed expands the type of veggies you can grow. Carrots, parsnips and other root crops do better with a deeper, looser soil.

Properly prepared, the soil will have much better drainage and will not get soggy. Raised gardens are easier to weed, maintain and fertilize. The soil also tends to warm sooner in the spring, helping seedlings and bedding plants get a better start. Stronger, more vigorous rooting is another plus.

• Tire tiers are miniature raised beds made from old tires stacked one to three high and filled with new soil. The heavy rubber sides act as insulation and a waterproof coating. A height of several tires will allow you to grow white and even sweet potatoes, which require deep, well-drained soils.

Make a good-draining soil mixture as described above. Start your spuds at the one-tire level and add another along with more soil as the tops keep expanding. These round mounds are also neat for cascading vines of tomatoes, cucumbers, small melons or ornamental gourds.

Whichever route you take, you don't want a soil that will get crusty and shrink too much, nor do you want one that is so heavy with peat that soil organisms will use all the nitrogen to break down the organic matter.

A little experience will give you a workable mix for your site.

Dale Langford is an area lawn and garden specialist.