Let’s look at some of the issues with raised beds in vegetable gardening.
Why raised beds?
I’m building raised beds throughout our garden as I have very little topsoil before I hit a shale limestone layer. Plant roots penetrate this layer nicely but it’s a tough layer to shovel or work. Building a bed on top of this ensures I can work with my plants without bending shovel blades.
Some people want raised beds because they can’t bend over as far as the ground. In this case, the beds have to be raised to the point where they can reach them (as in the picture). This is essentially container gardening.
There is a myth out there that raised beds outproduce in-ground beds. This isn’t true but the myth continues. Bottom line – if you spend as much time building soil in-ground as you do on raised beds there isn’a t difference. But raised beds get more attention because they’re “sexy” so they appear to produce more.
You can make your own super-soil. I’m currently building raised beds for Mayo’s vegetable garden area. Last fall, I cleaned off the grass and mulch that was there. Laid down 2-inches of manure on the ground. This spring, I’ll build 8-10 inch side walls and fill with a combination of top soil and peat moss. Mix it with the manure and we should be able to have a rather nice soil.
With some construction before-thought you can design for tubing on the sidewalls to bend over the beds to form mini-greenhouses for frost protection at the beginning and end of the season.
Space efficient. Because it’s essentially container gardening, you don’t grow in long rows but in short rows or using grid planting systems for intensive gardening. With a width of less than 36-inches so you can reach the middle easily from either side and narrow pathways, the beds are great examples of intensive gardening.
Our raised bed for vegetables
Take more water. A raised bed has a mechanical disadvantage in that water will go down slightly faster in the bed than in the surrounding soil. So you do have to watch the watering in a raised bed more than in garden soil
Evaporation from the side walls. Water will leave the raised bed not only from the top and bottom (as a natural level garden) but also from the sidewalls.
Prone to temperature fluctuations – earlier to get soil temperatures higher in spring and earlier to cool off in the fall (it’s those pesky sidewalls again)
There is virtually no difference between growing in a raised bed and growing in the ground. The difference is going to be in the increased amount of water the raised bed will consume.
All other variables – from feeding to weeding through harvesting and insect/weed control is going to be the same.
Anything that holds soil. 🙂
I know folks want “cheap” but in all things, you get what you pay for. If you use pine, there’s a shorter life than if you use cedar. If you use cement blocks, there’s a different “look” than if you use the manufactured stone wall material readily available in garden shops.