Need advice on raised bed construction

[kubota4me]

I had a guy quote me a price of $275 for a fabricated steel raised bed made out of 10 gauge carbon steel with reinforcement throughout. The dimensions would be 24" high x 4' x 8'. I wouldn't have to worry about it ever deteriorating (rust wont hurt anything). Green treated lumber is a concern of mine because of the chemicals. The steel one would not require any labor. Your thoughts are appreciated.

 

[jinman]

I would build the frame out of treated lumber and then line it with corrugated galvanized 26 ga sheetmetal. I believe I could build three of the size you want and still be under $275 for materials.

 

[charlz]

If you google image search "metal roofing raised beds" you will see pics of what Jinman mentions. If I had to build new ones that is probably what I would go with. You could possibly get some used steel roofing off craigslist or the like a lot cheaper than new roofing if you wanted that look.

I do like the 24" depth though. I would not fill it all the way with dirt though. Leave 4-6" above the edge of the beds so when you add compost, leaves, straw etc. the edges hold it on the beds and it doesn't drop all over your walkways. After 13 years off adding stuff my raised beds are mounded now and I always end up raking dirt off the edges. I could remove dirt but the nice stuff on top is what I have worked so hard to build with compost and other amendments.

 

[deezler]

What? that's craziness.

Just build it yourself out of untreated 2x lumber. Sure, it may rot after 10 years, but it's a freakin raised bed. Who cares. It's not like it's a structural element of any kind, it just retains a few inches of soil. Even if it rots 50%, it'll hold together for a long time. I have a raised bed built with 1x untreated lumber holding strong after 5 years now. el cheapo, for sure.

You are correct to keep treated lumber well away, it will leach out and around over time. I wouldn't used galvanized metals either, because they will be coated with other chemicals / paint.

Untreated lumber is by far the easiest. If you want more permanence, you can build them out of concrete block / pavers.

No need for it to be 2' high. 1' is more than enough height to hold a whole lot of nutritious fresh dirt (compost). Excavate down a bit first with your 4400 if you want.

(just my opinions).

 

[Mudfarmer]

I built mine out of rock built up as high as two feet laid as dry wall. Lasts forever, reasonably cheap. Even if you don't live in a rocky area, you could use landscape blocks from Lowe's instead. Easily removed (I used "1/2 man" rock). Looks nice forever (with the occasional rock adjustment). Holds heat during the night to keep those spring seedlings warm.
Mf

 

[randy41]

24" is very deep. i used untreated 2x8's filled with compost.

 

[charlz]

You are correct to keep treated lumber well away, it will leach out and around over time. I wouldn't used galvanized metals either, because they will be coated with other chemicals / paint.

The lumber thing has been debated but in this case the wood doesn't come into contact with the bed soil, only the posts are in the ground below the bed. I have never heard of any concerns around galvanized steel roofing and galvanized roofing has no need of other chemicals or paint. Galvanized water pipe has been used for many many years so I fail to see where you get your concerns from.

No need for it to be 2' high. 1' is more than enough height to hold a whole lot of nutritious fresh dirt (compost). Excavate down a bit first with your 4400 if you want.

The higher the bed the less bending and the easier it is on the back.

 

[deezler]

The lumber thing has been debated but in this case the wood doesn't come into contact with the bed soil, only the posts are in the ground below the bed. I have never heard of any concerns around galvanized steel roofing and galvanized roofing has no need of other chemicals or paint. Galvanized water pipe has been used for many many years so I fail to see where you get your concerns from.

The higher the bed the less bending and the easier it is on the back.

As soon as it rains, the treatment chemicals in the wood can leach out and easily come into contact with the soil. What posts are you talking about? You would drive posts into the ground to support a raised bed? Sheesh. Just toss some untreated lumber onto the ground, screw the corners together, fill with dirt, and you're done.

I was referring specifically to the corrugated galvanized roofing (as was suggested). Does that look like simple, unpainted galvanized metal to you? No, it's covered in layers of paint and other unspecified coatings. Go to a roofing manufacturers website and check it out. Are those chemicals you want in your food? Who knows, but not worth the gamble (IMO). Galvanized pipe, on the other hand, is plain metal and uncoated.

You're certainly right about higher beds meaning less bending over. But for cheapskates like me, lower is simpler, and much cheaper (half the material and soil cost, or less).

 

[jinman]

24" raised beds make working the bed much easier on an old back. Here's an article from the Noble Foundation in Oklahoma.

 

[kubota4me]

I've had back surgery and still have herniated discs so height is an issue for me. I'm also a cancer survivor who eats organic so chemicals leaching out of treated lumber is also a concern. I like the idea of corrugated, galvanized metal raised beds. I ran across a couple of designs and wondered what you guys thought of them.

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