Compared with planting directly in the ground, raised beds are easier to maintain, promote better plant growth and prevent soil compaction, which can cause drainage problems. Compaction also can decrease the availability of oxygen to roots and make weeding more difficult.
Raised beds can easily be filled with high-quality soil, compost or other organic matter. Plants grown in raised beds get better air circulation and use less water. In our area, this is the best way to grow root vegetables, such as carrots and potatoes.
Growing in raised beds is easier on the gardener, too. Gardeners in wheelchairs, those with bad backs or bum knees and those who might have limited flexibility all benefit.
Raised beds are also ideal places to grow plants that can be invasive in a regular garden, like mint.
Building a bed that will provide years of service is a simple job — but it must be done properly to achieve the best results. There are many books and Web sites that have great information about how to build raised beds, so I will just make a few suggestions that I feel are necessary for beds in our area.
Till compost (or another soil conditioner) into the soil below where you plan to build your beds. This will give plants with roots longer than 1 foot the best possible growing conditions. Lay galvanized chicken wire or half-inch (or wider) hardware cloth over the prepared soil and under the beds all the way to the sides. This will deter gophers and moles from attacking your beds.
Construct the frame from nontoxic materials, and avoid treated wood. If snails are a problem in your garden, you might want to consider attaching a band of copper around the frame. Snails are repelled by copper’s slight electrical charge.
Fill the frame with the highest-quality soil blend available. Topsoil, potting soil and compost are all great candidates. Organic material breaks down over time, and compost will need to be added regularly.
If you do not plant winter crops, cover the beds with a couple of inches of leaves, compost or a cover crop, such as clover or fava beans, each fall. Turn under the cover crop or leaves in the spring, then plant again.
• UC-certified Master Gardeners are available to answer gardening questions from 9 a.m. to noon Tuesdays, Wednesdays and Thursdays at 953-6112 or firstname.lastname@example.org. Questions for Heather Hamilton can be submitted to email@example.com.