Raised Beds provide the ideal growing environment: control over soil quality, good drainage, deeper planting beds, protection from soil compaction (since they aren't walked on), improved pest control, protection from invasive roots, and easier accommodation of season-extension tools such as row covers and cold-frames. Studies have shown that most raised bed gardens beat row-crop gardens hands down.
Good Drainage - Very important to all vegetables and herbs.
Extended Growing Season - Soil warms more quickly in the spring and stays warm longer in the fall. Easy to add row covers and cold-frames for even more protection.
Frugal - Water and fertilizer can be concentrated where they are needed.
Easier - Easier to plant, weed, harvest and tend.
Keeps Out Invasives - Invasive growers and weeds in the surrounding area are kept out of the vegetable beds. If this is an issue you are battling, be sure to line the bottom of the bed with a good 1/2 inch of newspaper and/or cardboard ensuring there are no gaps and the ground is completely covered.
Buy or Build
Many raised bed kits are available for purchase (see the Resources box at right) or you can easily build your own.
Build Your Own Raised Beds
Raised beds can be any shape or size but the most practical are no more than 4 feet wide, so that the contents are easily reached without stepping into the bed. Typically, they are a box with an open top and bottom placed on the ground. Great tip: line the bottom with 1/4 - 1/2 inch of newspaper or cardboard before adding the soil mixture. This will smother any weeds lurking below. Eventually, the paper will rot and allow roots from plants to penetrate for deep root growth. If gophers are a problem in your yard, staple heavy-weight chicken wire to the underside.
Instructions To Build a Basic Raised Bed - 4 foot wide x 8 foot long x 1 foot deep
- (3) boards of cedar or redwood (naturally rot resistant) 8 feet long, 1 foot wide and 2 inches thick. Cut one 8 foot board in half to make the end boards. Galvanized wood screws.
- 4 foot two-by-four-inch cut into four 1-foot pieces. These are the corner pieces that add stability.
- Lay one 8-foot side board flat on the ground and attach a corner piece to each end with the four-inch side of the corner board next to the 8 foot board. Repeat with remaining 8-foot side board and corners.
- Stand up on end the side board with it's corners and attach an end board to the exposed end of the 8-foot board and the corner board, creating half of the box. Repeat with other side and end board. Attach the two halves.
Gardener's Supply offers nifty raised bed corners that simplify construction. The corners are pictured at right in the Resources box.
For step-by-step instructions on building your raised beds from scratch, get the book The Vegetable Gardener's Book of Building Projects. It's currently on sale for only $13.27. In addition to instructions on building raised bed there another 38 simple-to-make projects - including cold frames, compost bins, planters, raised beds, potting benches, gates, trellises, storage containers and outdoor furniture.
A variety of non-toxic materials can be used to build a contained raised bed, including stone, brick, concrete blocks and untreated wood that is naturally rot-resistant, such as cedar or redwood. DO NOT use pressure-treated lumber — it can leach toxins into the soil and contaminate your food. Most commonly, raised beds are made from wood or wood-like materials. If cedar and redwood are too pricey for you, use this recipe from the U.S. Department of Agriculture to preserve less expensive untreated wood.
*WARNING: Although this recipe was published by the USDA and reprinted in organic gardening books, the individual ingredients are toxic and potentially dangerous. The safest and easiest approach is to use natural untreated wood.
The ideal soil mixture for vegetable gardens (and just about any other plants) is half good-quality top soil and half good-quality compost with some coarse sand or grit mixed throughout. If you are happier with percentages adding up to 100%, then approximately 45% top soil, 45% compost and 10% grit. The quality of top soil and compost can vary widely. You should check out the product firsthand before purchasing. Some suppliers offer a 50/50 Mix of top-soil and compost which is great when you can find it. The coarse sand and grit improve drainage. Do not substitute "play sand" which is something completely different.
Visit the Vegetables Forum at GreatLakesGardeners.com to get answers to your growing vegetables questions. To ask a new question, Register if you haven't already done so(it's free and helps protect the forum from spam), click on Start New Topic, enter your question and click on Post New Topic.
You may also appreciate these books on growing vegetable gardens.