Building a raised garden bed with corrugating metal roof panels

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Kennedy
Posts: 531
Joined: Mon Nov 10, 2014 2:47 pm

Building a raised garden bed with corrugating metal roof panels

Post by Kennedy » Mon Jun 29, 2020 5:03 pm

Years ago, I built a raised garden bed out of un-treated cedar. (I read that using treated wood in a garden was not a good idea due to potential toxicity issues.) Everything was fine and dandy for about two years until the wood started to rot, and the whole thing collapsed. Apparently, that is a pretty common complaint.

I found articles online of people building raised garden beds with corrugated metal roof panels for the sides instead of wood. I'm assuming longevity isn't as much an issue, but I'm concerned about whether anything "bad" could leach into the soil and be uptaken by my plants. I read a few accounts that says the zinc coating on the panels could only be compromised by acid, and that it wouldn't be an issue in a raised garden.

Does anyone here have any thoughts on using metal panels in a garden? Helpful tips? It would look something like this:

http://blueberryhillcrafting.com/2013/0 ... rden-beds/

iamlucky13
Posts: 1898
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Location: Western Washington

Re: Building a raised garden bed with corrugating metal roof panels

Post by iamlucky13 » Mon Jun 29, 2020 6:40 pm

2 years is really short for cedar. Strange.

I spent several hours researching, including reading actual science papers. Per forum policy, I will limit the discussion to what I learned about effects on the plants, and effectiveness at preservation.

I used treated lumber...Actually, I treated it myself to save money, using copper naphthenate, rather than buy normal copper azole treated lumber (the old chromated copper arsenate treatment was phased out for most treated wood a while back). In retrospect, treating it myself took so much time it wasn't worth it, especially since pressure treatment with copper azole is significantly more effective at preserving wood than brush-on treatment with copper naphthenate.

One of the papers I read compared numerous treatments to untreated wood and found almost no detriment to plant growth from copper naphthenate when it was allowed a month of drying time before use to allow the solvent to fully evaporate. They didn't test shorter drying periods.

I did not have a month to spare, so I stapled 4 mil plastic on the sides as a barrier. So far, so good.

It doesn't sound like there is major concern about zinc affecting your plant growth, but you could try a similar barrier if you're concerned.

Carpenterant
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Re: Building a raised garden bed with corrugating metal roof panels

Post by Carpenterant » Mon Jun 29, 2020 7:33 pm

I use scrap 2x and/or 1x, usually some sort of construction material, paint it and grow. 2 years seems really short, especially for cedar. My oldest one is about 7 years and no signs of rot termites etc

Silverado
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Re: Building a raised garden bed with corrugating metal roof panels

Post by Silverado » Mon Jun 29, 2020 7:37 pm

A couple down the road from us did this. It looks horrible to me, but it appears to hold in the dirt which is about all I would expect is needed from a raised bed.

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LiveSimple
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Re: Building a raised garden bed with corrugating metal roof panels

Post by LiveSimple » Mon Jun 29, 2020 7:52 pm

Using untreated wood, Douglas Fir, this is the second year, I do not think the wood will rot in at-least next 5-7 + years.
Even if the wood rot, the soil will stay raised, as we can mold the sides.

ballons
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Re: Building a raised garden bed with corrugating metal roof panels

Post by ballons » Mon Jun 29, 2020 8:11 pm

You can find websites about "leaching" for just about every single thing.

Other than accidentally opening up an artery from cutting that much corrugating metal roof paneling, there is nothing really to worry about. If you have the cash, get stock tanks. e.g. https://www.tractorsupply.com/tsc/produ ... _vc=-10005 You can see in the pictures from your OP they have them as well.

There is also concrete blocks and natural stones to use for beds. I use concrete blocks.

Mr. Rumples
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Re: Building a raised garden bed with corrugating metal roof panels

Post by Mr. Rumples » Mon Jun 29, 2020 8:32 pm

My neighbor is using metal panels. With plastic PVC pipe holding up chicken wire to keep out the critters, it looks substantial. He said, the soil is basically neutral for a garden so its OK. My beds are gradually building up since I mulch with straw and plant a crop of green manure each fall. I have a lot of trees and I use the limbs which are removed by the trimmers.

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