By Mark Levisay
Raised beds don’t have to be complicated, or expensive. Their main function is to enhance drainage in rainy weather, and allow you to enhance the soil, especially if your area has a lot of rocks or clay. Three or four inches is all you need to achieve those goals.
Size and access
Let’s think first about bed size and access. You should be able to easily reach into the center of any bed you build, so your arm length may be the ultimate guide for bed width. If your garden has a fence, you can make beds along the fence 2 feet wide or so, which allows easy access from just one side, and can support large plants such as a row of tomatoes or peppers, or lots of smaller plants. In areas where your bed will allow access from both sides, four or even five foot wide beds can work. A bed this size could contain two rows of peppers or tomato plants, or even three rows of something like beans or beets. Just remember you want to be able to easily reach the center of the bed, as you never want to step in the bed to avoid compaction.
Bed length is determined by your overall garden space. Some folks go with a “four square’ that is four feet on every side, with easy access from any side. Many of my beds are twenty feet long, as row cover material often comes in either 20’ or 50’ lengths (I cut that in half and use two 6’ wide strips to cover a 5’wide bed).
You should leave “paths” between your beds to allow easy access for you and maybe a wheelbarrow or wagon so you can get your tools and produce in and out. Three feet or so should be plenty for a path.
Soil
You don’t need fancy soil for your raised beds, especially if you are building them in an existing garden space. The nearest source could be your designated pathways. Dig a few inches of soil out of your path, and pile that on your beds. Mulch the path to keep your feet out of the mud, and you’re good to go! If you have a really rocky site, or one with heavy clay, you may need to bring in soil. There are numerous local contractors who can deliver really nice “top” soil by the yard, or for smaller projects you can buy bagged products. Some are even called “raised bed soil” which seem to contain a lot of organic matter to promote good drainage. Always plan to use some amount of mulch on the top of the soil, which will inhibit erosion and soil splash (especially important for tomatoes) and retain moisture in dry weather.
Structure
Do you really need to have physical edgings for your raised beds? You don’t really need edging, especially if you have a fairly level site. If you’re on a slope, physical borders can help create terraces that create level beds on the slope. Edgings can also give you a place to kneel when you access the beds for planting, weeding or harvesting. I’ve used a lot of landscape timbers over the years but found that they rot out pretty quickly. I may switch to landscape blocks which are designed for retaining walls and garden edges. This may cost a little more but should be permanent. Railroad ties, bricks, logs, or cedar boards (naturally rot resistant) will also work depending on your site and what you feel comfortable working with.
If you put in a little up front effort you’ll have garden beds that will work well for you in any kind of weather for years to come. Good luck!
Have a garden question? Send me an email at marklevisay@gmail.com.