Raised Bed Gardening by Wayne Bowman, Master Gardener.
Spring; time to look ahead to planting, growing, and eating our own fresh vegetables. So, you thought you’d try your hand at raised beds, since you don’t have loads of space. Great! First, though, you’ll need to build it, and planning is the key.
When planning your raised beds, placement, materials, size, and use must all be considered.
Placement: Just about any nearly flat surface is good. For many, however, there’s another consideration; the Home Owner Association. If you live in a developed community or an urban setting, it might mean your HOA has restrictions on where and what you might build or grow. City zoning restrictions may apply too. It’s best to check before you buy the lumber, or you may be paying for more than just the nails.
Materials: This is subject where you can be quite creative. A neighbor uses several stock troughs for his. My wife used hay bales, which lasted a few years. When the bales rotted they became a great amendment to our black soil. Bricks, concrete blocks, or anything that will contain soil are all useable. The bed can also be purchased in kit form, ranging in price from around $50.00 to several hundred. By far the most common is the do-it-yourself wooden bed, but I’ve seen pre-fab beds in metal too.
Choose something that is rot and insect resistant. Cedar is a good choice but expensive. Preservatives in treated lumber have changed and are no longer as toxic to humans as they once were. Use the type rated for ground contact. If you still have concerns about the chemicals, as some do, a plastic liner or coating the wood with a sealer will prevent most chemicals from leaching into your soil. Under no circumstances should you use old railroad ties. They’re great for retaining walls or lining driveways, but still retain a lot of the preservative creosote, which is both toxic and corrosive. Never a good combination.
Size: This depends on how far you can comfortably reach and your available space. You’ll want to make sure you can reach the center of the bed without stepping into it. Consider, too, if your kids will be helping you and size the width of the bed so it’s within their reach. Two 8 ft 2×10’s can frame a 4 ft by 4 ft bed nicely. If you’re thinking bigger and have the room, go longer, rather than wider. How high the bed is raised should be considered. For those of us who are a bit more advanced in age, the bed can also be built on legs, eliminating bending and stooping.
Use: Wow! This is a subject that would take a book to cover. In fact, there are many that do. Done carefully, even corn can be grown. I would shy away from plants such as pumpkins. My wife did this one year and it overgrew the bed, far into the lawn! My best advice is to grow what you like to eat or look at.