I inspect my raised beds each spring before I begin planting. At first glance, my wooden garden boxes appeared to be in fair condition. However, on a closer look, the inside boards were rotten and splitting. It’s been six years and I should have expected to have to replace some of the deteriorating boards and in some cases, the whole box.
I must admit, I love the look of wood and its ability to break down and return to soil. However, we need raised beds that will last longer and require less maintenance over the years, so we have to consider sustainable materials. We decided to create simple concrete block beds and install galvanized steel raised beds. These materials aren't impervious to decay over time, but their lifespan ranges from 35 to 75 years or much longer, if properly cared for, compared to our wooden beds that need to be replaced far more often.
If you know where your concrete bed will remain, I would suggest using mortar between the blocks to secure it in place.
I have a tendency to redesign or change my mind, so no mortar for me; just one concrete level made into a square or rectangle – a simple layout which will secure the soil in the center and allow for smaller planting along the edge. The blocks are designed to be crack-resistant, and the newer blocks won’t leach chemicals into the soil like the recycled ones from older homes. Please stay away from those old blocks when building your garden beds.
Galvanized steel raised beds have a nice look and are quite sustainable. They are coated to prevent chemical leaching, or rust, and many are lightweight and easy to setup and install. We plan to use the foot-tall raised beds since they are more affordable, and we can use less soil than the taller ones. If we forget to water the plants, their root system is still close enough to the ground to reach the accumulated moisture. Unfortunately, unlike the wooden or concrete block beds, we cannot rest or sit on the top edge but we can count on the steel beds to last about 50 years.
As you upgrade your planter boxes, consider using sustainable materials that could give you many years of use and lets you focus your energy on caring for your plants.
To learn more check out these resources:
VA Cooperative Extension - Comparison of RaisedBed Methods, Materials, and Costs
Univ. of Maryland Extension - The Safety of MaterialsUsed for Building Raised Beds
-Shana
