A labor-saving tip that I recently came across suggested consolidating crops in raised beds to reduce our gardening workload.

The idea isn't new and it does have merit, but gardening in raised beds still requires effort. I find it very satisfying despite the annual chores that I'll be facing once again in the next couple of months.

My first vegetable and strawberry beds suffered from poor soil. When I learned how to amend by mixing in compost and aged manures and scooping up soil between beds, the growing areas became raised almost by themselves, with pathways all around.

Yet these growing areas still required the same attention that any other garden bed needed — replenished organic matter, watering, weeding and fertilizing.

The greatest advantage was not less labor but improved drainage in winter and easier irrigation in other seasons.

I became committed to my simple raised beds until raccoons succeeded in dislodging the rock borders and moles created even more havoc as they probed for worms under the mulch.

It was time for more permanent structures.

Thanks to my husband's expertise, most of my vegetable garden now consists of three boxes, 12 feet long by 4 feet wide by 2 feet high, built with 2 x 12 pressure-treated boards and 4-inch posts, topped with 2 x 6 redwood trim all around, wide and sturdy enough for sitting and holding containers as I work.

Although the lumber is considered no threat to edibles, I lined the interior sides with heavy-duty black plastic. Quarter-inch hardware cloth covers the bottom.

Despite their good looks, convenient height and sturdy construction that protects crops from critters, these beds are not maintenance-free.

Managing beds

<MC>If you're new to container gardening and raised beds or are unsure of how they function, you may be surprised at the changes that occur each year.

If you've made the mistake of filling a container or free-standing raised bed — a pot, a half barrel, or any other structure — with only garden soil, you'll need to make some serious adjustments.

Either replace the soil with a purchased container mix or create your own with nearly equal amounts of small lava rock, pumice, or perlite; fast-draining native soil or purchased loam or coarse sand; and compost.

Garden soil compacts so readily that it is unsuitable as a single ingredient in containers. In fact, it is completely unnecessary as long as you provide adequate nutrients.

Some gardeners, however, insist on including garden soil when growing vegetables, trees, and shrubs in containers. It is never necessary for growing annuals in pots.

After 2 or 3 years, expect the soil level to drop as much as 20 percent in a raised bed or container as organic matter decomposes. Because stable ingredients remain intact, only the organic matter — such as compost, peat and manure — needs to be replaced.

In large constructed beds such as those in my garden, this is a big job. I actually stand in each bed, turn over at least a spade's depth of soil and mix it back in with compost and aged manure, sometimes using my lightweight Mantis tiller.

If you don't relish this amount of digging, simply working in fresh compost into the top few inches and letting worms do any further mixing is another solution. Soil at the bottom will remain more compacted, however.

Weigh the advantages

<MC1>One of the greatest advantages of raised beds is protection against gophers and moles. To be completely effective, a barrier must be securely in place when you first build the bed.

Some gardeners have used ?-inch galvanized hardware cloth successfully but only ?-inch openings will also exclude voles. Openings in chicken and aviary wire are too large and the wire in these materials will break down over time.

Two gardeners I know have built raised beds to escape invasive tree roots but have been disappointed when roots from their own property or a neighbor's found their way into raised beds nonetheless.

In this situation, there are two choices. Either rebuild and line beds with an impenetrable material that will exclude wandering roots, or support small raised beds on blocks a few inches above ground, so roots cannot reach.

Rosemary McCreary, a Sonoma County gardener, gardening teacher and author, writes the monthly Homegrown column for The Press Democrat. Write to her at P.O. Box 910, Santa Rosa, 95402; or send fax to 664-9476.