False economy is when you think you are saving money but you aren’t. One of the classic false economies is when you buy a lot of something (say, broccoli at Costco) for a very low per-unit price but then due to spoilage end up throwing away half of what you buy. The effective per-unit cost ends up doubling, and your real cost is more than it would have been at the regular supermarket or even the yuppiehippie market.
Life is full of false economies – they are wonderful marketing tools. Upmarket cell phone plans and cable TV packages all depend on a perception that you are getting “more” of something per dollar spent even if you don’t really need (or use) that something.
But false economies don’t just happen at the hands of mass marketing campaigns or warehouse stores. We can suck ourselves into a false economy when intuition makes the decision instead of a slightly more reasoned look at the numbers. Take garden beds…
Prevailing wisdom says that you should build your raised garden beds out of some sort of resilient material. If you don’t mind getting a little copper and arsenic in your veggies, go for pressure treated lumber. If you prefer to avoid the symptoms of heavy metal poisoning (hair loss, stupor or confusion, renal failure, etc.), choose one of the more resilient forms of wood, like cedar or redwood. If you care to embrace technology, there are plastic or composite materials like Trex to consider. Stone is long lasting and truly lovely, as long as someone else is buying it.
We’ve gone a different path in our family garden, and let me tell you about why.
Pressure Treated: did you get the part about the cupro-arsenic preservative? Sure, you could line it with a barrier layer, but now you are just complicating things. Expected life span 10-15 years. Estimated cost for one 4′ x 8′ bed: $60.79.
Cedar: luscious, resilient, smells great when you cut it. Western Red Cedar is a lovely native species and would build beds with an 8-10 year lifespan. Cost: $80.49.
Plastic and composite: I’ve never seen one of these that I like. They all seem to start to bow out in the middle or require extra bracing. They also lack the heft of a good dimension lumber bed that gives a nice 1 ½ inch rail to set tools, coffee cups, beer bottles, etc. on. Google around and you’ll find tons of them, such as the popular Earth Easy kit that goes for $239.26 for a 4′ x 8′ bed. I found this UL-T-MATE kit at Amazon.com for $99.99 and it seemed not-half-bad (made of what is presumably some sort of wood/resin composite)…until I realized that it was a hundred bucks for a 2’ by 4’ bed. Ouch.
Stone: the kids are going to need braces one day. Too much money. Way too much.
Hem/Fir framing lumber: this is the cheap stuff, the nothing-special building material that is stacked up by the palate full at any big box store or lumberyard. The big drawback is longevity: in our (wet) climate you’ll see this stuff start to rot in 3-4 years and be sufficiently far gone that it requires replacement the year after that. I’d figure a lifespan of 4-5 years based on our experience, though some of our beds are at six years and still going strong. Cost for one 4′ x 8′ bed: $22.77.
By the way, I got all the prices from the lowes.com website for the pressure treated and hem/fir. Assumption is that a single bed requires 3 8’ lengths of 2×12 (I couldn’t find cedar in 2×12, so I assumed a two-high stack of 2×6). I’m ballparking screws as each bed requiring 1/10th of a 1lb box of Grip-Rite 3.5” x 10 deck screws – $0.87, in other words. This is a very generous allowance!
Crunch the numbers and Hem/Fir is less than 40% of the cost of the pressure treated and less than 30% of the cost of the cedar. For about 50% of the life span.
Now I can hear the objections: it is a lot of work to build these beds, I want to do it once and then forget about it. My responses are “no” and “you’d have to do it anyway.” In other words, it actually isn’t hard to build or replace the beds. And none of the other wood bed options really are “lifetime” solutions. Less frequent, perhaps, but not lifetime.
Here’s how I do it: Go to the lumberyard and get the needed materials. You need 3, 2×12″ boards for every bed you are building. Cut one of them in half to make 2, 4-foot lengths. I do this assembly-line style and start by doing all my cutting, stacking the half-lengths.
Then I marry up half-beds each consisting of one half-length and one full length. I prefer to build my beds “long” where I attach the short side to the end of the long side. I do this on the garage floor, where the 2×12’s will stand on their sides. Don’t worry about getting things exactly true. This is a garden bed, not a Space Shuttle. Depending on my mood, the number of screws I have left, and the charge in my drill, I will use 4 to 5 screws to secure each half-bed together. Screw through the flat of the short side and into the end of the long side. Again, assembly line is the key. I bust these out and have them sitting on the garage floor.
Now, one at a time I carry the half-beds to their intended location. I set one down, get the next one and position it correctly. I always feel like I am carrying giant letter L’s on my head while doing this. Once both bed halves are in situ, I align them and screw the remaining two corners together. Depending on the same variables as above, but also whether or not it is raining, I’ll secure the two half beds together with 3 to 4 screws in each corner.
In the past, I’ve used more screws and extra pieces of lumber to brace the corners and midspan of the bed. Experience has taught me that, for 8′ long beds, these things are not necessary. In fact, I suspect that more screw holes just create more places for water to intrude into the wood and actually harm bed longevity.
I can run down to the store, get the lumber, and have a half dozen beds built up and ready to deploy by lunch. And if you’ve got as many raised beds as we do (16 at current count, probably another half dozen or so coming this spring), the cost savings can be considerable. Sixteen cedar beds that don’t need replacement for 10 years would cost $1,287.84. Sixteen hem/fir beds, each replaced once is only $728.64.
Replacing an existing bed might seem like a big pain in the backside – but really it is no more work than building a new bed. We use this as an opportunity to amend our beds, check soil quality, and work the tilth a little. Call the bed undergoing replacement the patient. Shovel a few inches of soil out of the patient into another bed. The bottom few inches of the bed are sufficiently compacted that they won’t collapse when you pull the sides away. If your soil is really good and loose, you might want to take a shovel and pull the soil away from the inside walls of the bed and just mound it up in the center.
Now unscrew the sides – just do the two opposite corners – of the patient. If you are using good deck screws some of them will be reusable. Cart away the rotten wood from the patient. We’ve considered saving some of the “healthy” wood but it just doesn’t seem worth it to me. Then bring in the two half-beds that you’ve built up, shove them up against the dirt pile and screw the opposite corners together.
If you want, you can refill the bed with some new soil, compost, manure, etc. You could do some lasagna composting to build it back up again. Like I said, this is a great opportunity to work the soil a few inches down.
Sure, more work than not doing anything at all, but trust me, not that much. And if we weren’t willing to put some work into this – if digging in the dirt and hammering together (ok, cordless drill/driver-ing together) – some wood wasn’t some sort of relief and joy, would we really be out in this garden at all?