I have gardening in raised beds on my mind these winter days. We are planning a schoolyard community garden in Eastport at the high school where I teach and where barely buried ledge leaves little topsoil in which to garden. You can’t drive a stake more than a few inches into the ground before striking a shelf of stone.
Students of all ages, K-12, will work and study together in this garden, mentored by teachers and community volunteers of all ages. Raised beds of varying heights, all wheelchair-accessible, seem the only way to go.
We thought about constructing the beds, each 4 feet wide by 8 feet long, from cedar timbers notched at their ends like Lincoln logs, and then realized that beds made from cinder blocks would be one-third the cost of the timbers. We’ll probably build some of both types, giving visitors a chance to compare.
We plan to fill the beds with screened loam amended with plenty of composted goat manure. An on-site composting program will provide a continuous supply of organic matter to dig into the beds each spring and to use as mulch.
Raised beds also can be constructed without frames. Only a few of the beds in Marjorie’s garden have wooden frames; few of them run straight. Most were formed by moving the soil from the walkways into the bed areas, adding topsoil when needed and digging in compost every year. The beds average about three feet in width and vary in length from several yards to just a few feet. The top surface of each bed is slightly narrower than the base to minimize erosion and the sides are buttressed with large rocks, of which there are always plenty.
We can plant, fertilize, weed, and harvest these beds from walkways on either side, avoiding compaction of the soil and thus improving drainage while allowing air, water and solar energy to penetrate to the root zone. The well-drained raised beds warm up faster in spring, giving us a jump on the growing season. They also hold the sun’s warmth longer at day’s end and in the fall — a real boon to northern gardeners trying to grow heat-loving vegetables such as tomatoes, melons and summer squash.
Laying out the garden in raised beds enables easy planning of crop rotations necessary to interrupt disease cycles in the garden and thus increase yields. Root crops, cole crops (broccoli, cauliflower, kohlrabi, etc.), and solanaceous crops such as tomatoes, eggplants, peppers, and potatoes, are particularly vulnerable to soil-inhabiting insects and diseases and thus benefit substantially from crop rotation.
Growing our vegetables and small fruits in raised beds has allowed us to make the most efficient use of our garden space and left us wondering why, in an age of smaller gardens and busier gardeners, would anyone use a planting scheme based on long skinny rows separated by wide expanses of cleanly cultivated soil? Studies show that only 32 percent of conventional garden space is used for plants compared to a full 63 percent for raised beds. The difference is in plant spacing; raised bed gardeners use the “in-row” spacing throughout the planting area, eliminating the “between row” space. In raised beds, the plants form a “living mulch” over the soil.
If you have yet to try raised bed gardening, why not give it a try next year? Start by tilling the garden area to improve drainage under the raised beds. Then mark out the beds with stakes and string, or with frames. Shovel topsoil from pathways onto the beds, rake them flat, and dig in 2 to 4 inches of compost. Finish by mulching the pathways around your beds with straw or wood chips.
If you prefer to frame your beds, be creative. Make your own frames out of logs, stones, cinder blocks, corrugated tin, or wood (cedar or spruce hold up best). Make the beds anywhere from 6 to 24 inches high, or even higher if you are like me and gardening on your knees is not as easy as it used to be.
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