Fall is here and winter will not be far behind. Here in zone 8, South Carolina, we are planting our second cool season crop, collards, cabbage, etc. For many folks across the country, gardening is pretty much done. That does not mean there is nothing to be done! Beyond the obligatory cleansing of tools, the clearing away of dead plant material, fertilizing, and the organization and storage of all the season’s gardening paraphernalia, here’s another idea. Why not build a raised bed garden?

Things to consider before you start building the raised bed garden

There are as many ways to go about building a raised bed, as there are gardeners. Some of the factors you’ll want to consider are space, your knowhow, the availability of tools and of course, cost. To spark your creativity, visit online sites like Pinterest where you can find inspiration.

The classic raised bed

Use 2×4-inch lumber which is relatively cheap and easy to handle. The boards can be cut to whatever size and shape you desire with a simple handsaw. However, untreated wood warps and rots when it is in contact with soil and water for extended periods. You can address this by using pressure treated wood, or even railroad ties. However, treated wood / railroad ties are soaked with chemicals. If you are planting flowers or shrubs, this may not be an issue. But, if you are growing edibles, you may wish to keep the chemicals from leaching into the soil.

The solution? Paint the lumber with a clear, safe lacquer to seal the chemicals inside. Eventually, even lacquered wood will need to be repainted every 3 – 4 years. Alternatively, wrap each board with a UV resistant plastic although even plastic will need replacement at some point. Another solution, line the bed with an old swimming pool liner. Make sure the liner has drainage holes. Otherwise, the only things you’ll grow are cranberries and rice.

The raised bed kit

Another way to create a raised garden bed is to purchase a kit. Make sure the lumber is either cedar or some other rot-resistant hardwood. The boards in a kit are usually gardener-friendly but individual pieces may still need to be sized and shaped. Depending on what part of the country you are in, a kit may double the cost of building a raised bed. Still, a cedar kit will last much longer, and to some extent, cedar helps keep certain critters out of the bed.

The bathtub raised bed

In the world of why didn’t I think of that, consider the bathtub approach. A couple of years ago I replaced a cracked fiberglass bathtub. I hated the thought of just throwing it away, so I decided to try it as a raised bed. It had all the characteristics of a good container, drainage (the crack as well as the drain hole) and it was slightly sloped so water wouldn’t just sit in the bottom. The tub’s material that would not rot or decay and it was safe for growing food. In my bathtub raised bed I planted asparagus. You might want to add ornamental grasses along the edges to hide the fact it’s a bathtub. Go ahead and get creative. Next time you are replacing something, ask if it could have a second life as a raised bed. You may end up solving two problems at the same time.

Once the raised bed is built, what do you fill it with?

If ten people are asked what is the best soil to use in a raised bed, they’ll give eleven different answers. In the end, the choice most likely will be based upon the plants to be grown and what is readily available. Peat moss, perlite, sand, pine bark fines, vermiculite, compost, garden soil, the list of possible raised bed materials goes on and on. There are several things to keep in mind. At the top of my list is drainage. While soil needs to drain, it also needs to retain moisture. Pure sand drains easily but water retention lasts only five minutes.

Another factor to consider is the stability of the plantings. Straight peat moss, for example, will not support a heavy plant. Further, if you allow peat to dry-out completely, it is very hard to re-introduce moisture into it as it will become hydrophobic. Once the materials to be used are identified, you’ll need to determine the proportions. That will be governed by the type of plants that are planned for the bed. For instance, if you wish to grow carrots, use a little more peat and perlite so that roots can easily penetrate the growing medium. Tomatoes or peppers, on the other hand will benefit from the use of more garden soil or compost in order to keep the plants upright.

Three reasons for raised bed gardens

As one gets older, it becomes harder to bend, kneel, or stoop, so why not bring the garden UP to you? Weeding, harvesting, pest inspection all become easier to accomplish. In the spring, the soil in a raised bed warms up faster, which will speeds germination. It is amazing how just a few degrees in temperature will make things grow faster. And, speaking of soil, if you have really lousy, clay-based soil, growing root crops can be almost impossible. A raised bed makes such crops much more practical.

A few final thoughts on raised bed gardens

Pretty much anything can be used to frame a raised bed, wood, metal, bathtubs, just as long as it can withstand a few seasons of sun, and water. Make sure the walls of the don’t poison your food. Beds need to be deep enough to grow the crop you desire. For example, a raised bed for potatoes should be at least 12 inches deep. Use a well-draining soil, which can still retain moisture. Don’t get yourself in a frenzy over the measurement of each component of the soil. Think of it like cooking, some of this, some of that, and a bunch of something else. Over the course of a couple of seasons, you’ll figure out what works best for the plants you are growing.

Happy Growing!