Experienced gardeners use raised beds to sidestep a long list of gardening challenges. These controlled experiments in plant parenthood are so easy, in fact, that they're also well-suited to novices picking up a shovel for the first time.Bad dirt is out, because you fill a raised bed with a customized soil-and-compost blend. Drainage is built into the bed walls, which hold the soil in place to keep erosion in check. Greater exposure to the sun warms the bed, which allows more plant diversity and extends the growing season. Plants can be spaced closely together, so yields go up, water-use efficiency is maximized and weeds are crowded out. Finally, raising the soil level by even a foot reduces the back-bending effort needed for jobs such as planting, weeding and harvesting.Beyond the ease is the control—as you grow your favorite foods, you feed and soak your plants with just what they need for optimum growth.A raised bed is most productive and attractive as a bottomless frame set into a shallow trench.
The sides can be almost any durable building material, including rock, brick, concrete and interlocking blocks. Watering troughs or claw-foot tubs can work, as long as they have the capacity and drainage.But by far the most common material for raised beds is lumber. The major caveat, since raised beds are often used to grow edibles, is to steer clear of wood preserved with toxins. Avoid creosote-treated railroad ties; opt instead for naturally rot-resistant cedar or redwood. The EPA considers wood infused with alkaline copper quaternary (ACQ) to be safe for food crops, but if you use this pressure-treated wood you may want to line the bed interior with landscape fabric—an air-and-water-permeable screen—to prevent soil contact. Whether using pressure-treated or naturally rot-resistant wood, put the bed together with galvanized or stainless screws or bolts. Pergola Plans: How to Build Your Own Pergola How To: Outdoor Fire Pit Ideas & Designs How to Build a Wooden Wagon
How to Make a Two-Board Backyard Lounger How to Make a Dumbwaiter How to Make a Box How to Build Leonardo Da Vinci's Catapult Build Your Own Beautiful Flat-Pack Chair Build This Update on the Classic Toolbox How to Build a Chess and CheckerboardPHOTOGRAPH BY BETSIE VAN DER MEER/GETTY Related: The Most Brilliant Raised Bed We've Seen Raised garden beds boost vegetables above potentially waterlogged grounds. Not every gardener deals with a high water table, but there are other good reasons to plant in raised beds: They are easier to keep free of encroaching grass than ground-level beds. Elevated soil warms earlier in spring and drains more quickly after a rain. Soil doesn’t become compacted because you don’t step on the growing area. Raised beds offer easier access for planting, thinning, weeding, and harvest. The following five raised beds are built from a variety of materials, described below. Each of these beds measures about 4 feet by 8 feet;
you can adjust the dimensions to suit your needs, keeping in mind that anything wider than 4 feet will be more difficult to maintain. Try filling beds with a rich mixture of about two parts soil and one part compost. PHOTOGRAPHS BY PATRICK MONTERO Hammer 2-foot lengths of rebar into the ground around the perimeter of the bed, spacing them about 16 inches apart and leaving 10 inches of the rebar exposed above ground. Cut long, straight lengths of tree or shrub branches, up to a 1/2 inch in diameter. Weave the sticks or “wattle” through the vertical rebar, basket style; trim the ends at the bed corners as needed. Once the bed sides have reached the top of the rebar, bend 2-foot sticks in half and poke them into the ground over the woven wattle, holding the sticks in place. Pin the sides in this manner every few feet. Line the sides of the bed with burlap to keep soil from sifting through the wattle. To build a 4-foot by 8-foot bed, you’ll need 18 pieces of rebar, each 24 inches long;
a strip of burlap about 18 inches wide and 24 feet long; and about 100 long, flexible sticks. Choose straight logs about a foot in diameter to create the bed edges. Logs of smaller diameter can be stacked, as pictured here. To avoid having to move massive logs, line up shorter firewood-length sections. To build a 4-foot by 8-foot bed, you’ll need two 7-foot logs for the sides and two 4-foot logs for the ends. Place concrete blocks with open ends facing up to outline the raised bed. The openings can be filled with soil and used as planting pockets for small herbs or edible flowers. To build a 4-foot by 8-foot bed, you’ll need 16 blocks, each meauring 8-by-8-by-16 inches. This bed can be constructed of leftover lumber of almost any dimension, so long as the wood is untreated. Hold the planks on edge with short lengths of rebar pounded into the ground every 2 or 3 feet. To build a 4-foot by 8-foot bed, you’ll need two 2-by-12 planks 8 feet long, two 2-by-12 planks 4 feet long, and 12 pieces of rebar, each 24 inches long.
Learn More: Check out our step-by-step guide to building a raised bed from lumber planks. Using the long, slender bags of sand that are sold as traction sand, outline a bed. Stack the bags two high all the way around the bed. To build a 4-foot by 8-foot bed, you’ll need 20 sandbags. Keep this field blank You may unsubscribe at any time.Thinking of building a raised bed this summer? There are several reasons why you might choose to build an above-ground structure in which to grow vegetables, herbs, and other plants: -To avoid toxics in the soil such as lead or arsenic -To avoid the drainage problems that heavily impacted or clay soils can present -To reduce back strain. Raised beds can be built at a good height for a wheelchair. -To add an aesthetically pleasing feature in the garden -To easily add nutrients to the soil -To improve yields by reducing the amount the soil is walked on and compacted -To clearly separate the growing area from the pathways for easier weed control
-To garden in paved spaces In this article, we will give you information for choosing the best building materials, recommendations for raised bed linings and depth, and a list of our favorite resources for plans. When choosing materials for your raised bed, consider durability, toxicity, environmental impact, affordability, aesthetics, maintenance requirements, and how permanent or portable you want your raised bed to be. Reused materials are the most affordable and have low environmental impact because they don’t require forestry, mining, manufacture, or long-distance transport. Find free or low-cost materials on Craigslist or Freecycle, at your local salvage yard, or in your own backyard! The Ecology Center’s Bay Area EcoDirectory contains resource listings, including local salvage yards. Building with low-tech methods usually saves money and minimizes environment impact. A low-tech method that permaculturalists favor involves building a mound of soil and straw directly on top of the existing ground, without a structure to contain it.
This method builds nutrients and adds tilth to impacted land, but if your aim is to avoid toxics, it might not be sufficient. Lining a Raised Bed Raised beds can be lined to make them more durable and to avoid the leaching of toxic substances into the soil. A lining can make an existing raised bed safer, but if your raised bed is made of creosote railroad ties or arsenic treated wood, it’s best to remove the wood from the yard to prevent continued migration of the toxics. For lining, use landscape fabric found at garden supply stores or cloth fabric from clothing. Avoid non-porous plastic, as it can retain too much moisture and discourage beneficial critters. Lining the bed with hardware cloth will help keep out gophers and moles. Stapling gopher/rat mesh to the bottom of the bed will thwart those pests. Treated and Untreated Wood Some pressure treated wood is toxic, while some is not. How can you tell which is which? The most toxic treated wood has been pressure treated with chromated copper arsenate (CCA), which can be identified by staple-like indentations and a greenish tint, which can fade.
Not all CCA wood has these identifiers. Wood that is pressure treated with Alkaline Copper Quartenary (ACQ) contains a very high level of copper and consequently, also appears green. ACQ treated wood is considered safe by conventional sources at this time. If the wood was purchased or the structure was built prior to 2003, the lumber was most likely treated with CCA.# To be sure, you can obtain an arsenic test kit, available at many hardware stores and online. If your existing raised beds were built with CCA treated lumber, you may wish to remove the structure to avoid the continued migration of arsenic through the yard. Dispose of it at a local waste facility; it’s categorized as construction debris. If this isn’t feasible, you might choose to grow ornamental plants in the beds rather than food. Even if the soil is replaced, the arsenic will continue to migrate into new soil. If you use untreated wood, you may wish to use natural wood treatments like flaxseed oil or wax.
Linseed oil can contain toxic additives, so it’s best to avoid it. A wide variety of borate-based “washes” exist to make wood resistant to decay and insects. They are safe around food plants. Determining Raised Bed Depth You will want to make your raised bed deep enough for healthy root growth. Plants will be stunted and may not produce well if their roots can’t reach down far enough into soil. If the raised bed is built shallowly, the roots will venture into the ground below unless it is too compacted. A floor or barrier is needed if you don’t want roots growing into contaminated soil. The following recommended Soil Depths are taken directly from Golden Gate Gardening: -6 to 10 inches: basil, beet, carrot short, chervil, chives, cilantro, lettuce, onion, green, parsley, peppermint, radish, spinach, thyme, dwarf cherry tomato, watercress, oregano, sage, marjoram. -10 to 15 inches: carrot, celery, Chinese cabbage, garlic, leek, lettuce, mustard, oregano, potato, strawberry, chard, dwarf patio tomato.