One central issue for people who rent their homes is how to garden in a restricted space. If all you have is a small patio or a landlord won't let you "dig up the yard," gardening can seem a bit more complicated. Fortunately, there are ways to get around this, and lessons in them for even gardeners with acres of land.
Advantages to Raised Beds & Container Gardening
A key advantage to container gardening is that one does not need as much soil. Although few could grow sweetcorn in a window-box, a five-gallon bucket will grow an impressive tomato plant or small plantation of peppers, potatoes or basil. Smaller containers can be used for smaller plants, such as herbs, and a raised bed, when you think about it, is really just a sort of container garden that sits in place. Both containers and raised beds share a few advantages.
The Advantage of Drainage and a Finite Space
Clark County has two main kinds of soils: volcanic andisols and fertile mollisols from the Missoula Floods. For areas that have been scraped and compacted and developed, though, these are often compressed and clay-heavy. They tend to get wet and to stay wet, which is a problem for many plants. Because they start as an empty vessel, container gardens can address this handily. Open-bottom pots such as those used in nursery's are designed to drain, as are most "flower pots." Rusted buckets drain naturally, and plastic buckets can have holes punched or drilled into the bottom. Uncertain about how much moisture a container will hold? Consider putting a coffee filter in the bottom, put in an inch or two of gravel, or both. Being able to monitor the soil in a container and assure proper drainage is one advantage of container gardening.
The Advantage of Warmth and Simpler Amendment
A finite container has the added advantage of making it simpler to monitor soil and add amendments. One can build "starter mix" completely from scratch using equal parts compost, vermiculite and peat moss, or simply amend existing soil with a bit of sand or compost as need be. Mint likes a different, wetter soil than garlic, and early spring soils in Clark County are cold as well as wet.
Vegetables need certain conditions to grow: nutrients and water, but also air and warmth. Although plants give off oxygen at their tops from photosynthesis, they need oxygen around their roots, which is why aerated soil with good "tilth" is so important. Spading the earth is one way to aerate soil, and the gradual decomposition of organic material (and worms!) are another. The lightest loam on the planet cannot grow anything, if the temperature is too cold. Plants use sunlight to help create sugars, but need "warm feet" to begin growing in the spring. By raising soil out of the colder earth, containers allow it to warm up more quickly, encouraging faster growth and quicker starts.
The Advantage of Mobility for Protecting Your Plants
Another advantage of container gardening is that plants can be moved from place to place and more easily protected. Very few patio gardeners need to worry much about deer, but there is always frost. Not all spots have good sun all day, or are simple to protect from cold rain or hail. The ability to move containers from place to place allows one to put them all together to be covered, moved to a sunny driveway for the heat of a June sun, or moved out of a punishing August one. Many garden centers have "plant skateboards" that can simplify moving large plants, and favorite herbs can even be kept indoors as needed. Digging potatoes is a fine way to spend an hour or so, but overturning a ten-gallon tub of dirt and picking them out is easier. The trick is to see the advantages and to make the method available work for you.
Getting Started with Herbs and Simple Plants
If one is interested in container gardening, a few simple herbs is probably the best place to start. Herbs are forgiving and tend to be small. Most people know what parts to harvest, and they are easy to identify. One can either purchase young herb plants ("starts") at a farmers market, garden center, or grow one's own. Simple herbs for beginners include: chives, parsley, basil and perhaps rosemary, cilantro or sage. Spinach and lettuce are also simple plants to grow. For larger containers tomatoes and peppers are a favorite, with several varieties to choose from. Potatoes can be grown in a container on the installment plan, starting with just a foot or so of dirt and gradually filling it up as the plants continue to grow. Spring starts can be moved outdoors, "repotted" into larger containers, with perennials such as chives divided to share at the end of season.
Raised Beds as Containers in the Garden
Gardeners looking to increase available space (or minimize stooping) may also use containers, putting them onto paths, under eaves or along borders where a "normal" in-ground garden might not work. Pots of potatoes or buckets of basil are one obvious use, and potted flowers can be moved around the garden to attract or repel insects, such as a flowering rosemary to consistently draw bees. The key biological advantages of a container also apply to raised beds in many cases.
Raised Beds Are Deep, Warm, Amendable Pots
Many of the things which are accomplished through spading down into the earth are simpler to do by raising the bed up, with the advantage that raised and contained beds are inherently out of a path and not subject to soil compaction. A raised bed is basically a bottomless box, and can be designed as "the best of both worlds," a hybrid container and flat bed.
Building Structures for Shelter and Water
Rather than digging into existing gardens to add an irrigation system, a raised bed allows one to build in irrigation and drainage from the very beginning, either through drain pipe or embedded sprinklers that encourage deeper watering. Examples of this may be found at the CASSEE center beds in Brush Prairie. A drain pipe filled with gravel at the bottom of a 12" bed not only provides drainage but can also be hooked to a hose for faster, deeper watering. Adopting a technique from German
hugelkultur, branches can be buried to hold deep water and provide extended aeration as they decompose. As any snake can tell you, rocks warm faster than grass, and stones placed along the south face of a bed will warm the soil faster than air, both of which warm up faster than soil beneath the general ground level. Raised beds can also be built to accommodate other protective structures such trellises, cloches or floating covers and netting of various kinds. A well-conceived raised bed is arguably better than a greenhouse, and much simpler to build and maintain.
One Example: Keyhole Gardens in Africa
One inexpensive and simple example of such a simple and sophisticated raised-bed garden are the keyhole gardens of Lesotho, promoted by the British charity "Send a Cow." Called a keyhole garden because their shape when seen from above, they basically consist of a round "chimney" built with a walled path that flares out and is open to the southern sun. This provides a warming structure and a built-in path to the center, much like "mandala gardens" here in the states. As well as providing thermal ballast to warm the soil, this stone chimney provides structure against which sticks and other woody material can be leaned to provide support for soil, which is then deposited on top, assuring adequate moisture within the soil and also good drainage. Because the garden is round, it provides different exposures or "aspects" for sun-loving plants (such as tomatoes and peppers) and heat-sensitive crops (such as lettuce) alike. A fancier version of this method popular among some permaculture enthusiasts is the "herb spiral," which replaces the thermal chimney with an integrated irrigation pipe.
Sheet Mulching Lasagna-Style to Build Beds from the Bottom Up
"Sheet mulching" or "lasagna compost" is another way to create raised beds. A "no-till" technique that takes time, it consists of placing material on the surface or into a raised bed, then waiting for worms and nature to do the rest. Adapting it for use within a raised-bed or bottomless box is simple, and can be done either before the sheet mulch ("lasagna in a box") or after, using stones or structures to contain the bed after it is constructed.
- Place a "weed barrier" of cardboard, overlapped to keep out all light
- Place compostable, nitrogen-rich material on top of this
- Cover this with "normal" soil, as rich and weed-free as possible
- Wait to let the worms and other soil creatures do their work
As the soil permeates the compostable material, it is inoculated with useful bacteria, fungus and other micro-fauna, as the weed barrier keeps seeds currently on the ground from taking over. As the compostable material decays, it gradually becomes more "normal" soil and the cardboard underneath decays, allowing integration with the soil beneath. Some advocate another layer of high-nitrogen compost (such as "hot" and fresh chicken manure) underneath the cardboard, to kill covered surface plants, but these will die and become compost anyway, when there is no light.
For Further Information
There are almost as many ways to do raised beds and container gardening as there are gardeners and kinds of containers, but the links below should help give you some ideas.
