Raised beds seem to be all the rage these days. From community gardens to backyards, they seem to have taken over the landscape as the preferable method for growing vegetables. Well, I’m going to let you in a on a little secret – the plants could care less. It’s not about the lumber, it’s about the soil.
- Height: Depending on how much money you are willing to invest in lumber (how high you are willing to build them), raised beds can make gardening easier for anyone with mobility issues or back problems.
- Good drainage: If the existing soil on your gardening site has areas where the water pools or it gets a little swampy, then raised beds can solve that problem by moving the soil above grade.
- Aesthetics: Raised beds give your garden a very neat, organized, and geometric look.
- Height: The higher you go, the more lumber and soil you need – so it can get costly. Moreover, in order to really save your back in a meaningful way, you have to build quite high, so the material cost could be triple or quadruple what it might be if you were simply building a low box to define the space.
- Good drainage: That excellent drainage will become a liability in July and August when everything is trying to grow rapidly and your gardens are starved for water. Here’s the thing: the water is always in the ground, not in the air. No one has to water a forest, because everything grows in the ground. If you plant above grade, you are planting above where the water is most readily available. The higher you go, the more of the problem this can become, and the more work your will have to do all summer long to deal with it. Conversely, if your gardens have a good mulch, and are at ground level, or only slightly above it, you may not have to water all summer long.
- Temperature: Because raised gardens are exposed on all four sides, they are not as well insulated as ground level gardens. In my experience, this means that they cool a little faster, and freeze up a little harder than ground level gardens. I have a couple 12″ high beds in my garden, and in the early spring, these are always the last to thaw.
- Unsustainable: At the end of the day, when you build a raised bed, you are most likely building it out of wood. You don’t have to be Mike Holmes to know that if you build something from wood, and then fill it with wet soil and bugs, it will eventually rot. Even if you use treated lumber (which is kind of toxic by the way, and I would not advocate growing food in a toxic box) it will still rot, and only at a slightly slower rate than untreated lumber. You also have to remove soil from somewhere, and then put it in your box, so your garden comes at a cost to whatever ecosystem from which the soil was initially gathered. No judgement, I’ve done it in the past too, just some food for thought.
If you bought yourself a Delorian, scrounged up a flux capacitor, set the dial to 1970 and floored the thing until you hit 88 mph, you’d find yourself back in the groovy past, looking at all kinds of incredible back yard gardens, and no raised beds. Why? The raised beds are about us, not the plants. We like them – but it’s not really about us. Think like a plant and ask yourself: What resources does the plant require? How do I make those resources as easy for the plant to collect as possible?
In the end, it’s all about healthy soil, sun, and the ready availability of water.
The main theme of all my arguments against the raised bed comes down to one of the key design principles of permaculture which is to copy nature. Think about it. You want healthy soil, and in order to have that you need all the living things that create healthy soil to be in your soil, and your soil needs to have all the conditions and resources that they need also. Well, all of those things are in the ground, so it’s so much easier to build that healthy soil when you are working with nature, rather than against it. It will be less costly and more sustainable to work with what you have and try to simply amend the existing soil with compost or manures.
If you like the way a box looks, and are able to knell or bend down, consider just making low beds, and consider other options for bordering, such as rocks, which last forever, leach beneficial minerals into your soil and also gather heat. I have found that even if the existing soil is terrible, a six inch high box is all that is necessary to add the amount of good soil that is necessary to dramatically improve growing conditions, and this is still low enough to the ground that the roots can still get to the water in the soil once the plants are large and the summer heat is on full blast.
If you still want height, either for aesthetic, health, or mobility reasons, consider building a raised bed that is a ‘hugelkultur‘ garden. This involves piling old rotten wood and logs into a row – say 2’ high X 2’ wide X 10‘ long, then piling leaves and small sticks over the logs, and then soil over the leaves. This a traditional approach to gardening that has been used in Germany and Eastern Europe for hundreds of year, and very space conscious because it actually increases the area available for gardening per square foot due to its geometry. Never the less, if a mound of soil sounds awful, and you must have a box, then just employ the same principle in your box. Pile lots of dead logs, sticks and leafs in your box until you have reached about one foot from the top, then fill the rest with good soil. What all that rotting material does is capture and hold water like a sponge, in addition to providing an ideal habitat for microbial life, and well as slowly leaching many nutrients into your soil. It’s a great solution to the height problem because on the one hand it saves you the cost of all the added soil, and on the other, it decreases your need to water. I guess an added bonus is that once all the wood that you used to make the box starts to degrade and rot, you can simply use it to make a new hugekultur garden. Zero waste! That’s permaculture at its best!