Acceptable Wood for Raised Bed Borders?

[bflocat]

We're planning to build 3 4' x 12' raised beds for our vegetable garden. In our area, it's virtually impossible to buy reasonably priced cedar to use for the edges (seriously, the cost is astronomical!), so our next option seems to be pressure-treated wood. I've read that it's ok to use CCA treated lumber, but around here, we've only been able to find ACQ treated lumber, which has supposedly replaced CCA, and is just as safe. Of course, this info comes from the manufacturer, so I was just wondering if anyone had any thoughts on the topic. What materials do you use for your raised beds?

[Roger]

Myself, I use old railroad ties purchased from the railroad. They sell them in my area at garden centers and the local farmer's co-op. These work wonderfully. I pay 8$ per timber from my particular supplier [they can be more expensive elsewhere, I understand] and they will last for decades. The only drawback I have found is that they do draw ants to the garden, most likely because of the traces of creosote on these old timbers.

This guy uses auto tires as bed materials I tried this on a couple of beds and they work great.
http://www.noble.org/Ag/Horticulture/RaisedBedGardening/index.html

[opabinia51]

Try searching google and finding out what chemicals are used in pressure treating those different types of pressure treated lumber and then looking up the MSDS of the chemicals to see what the environmental impacts are.

Personally, from experience if you just use regular lumber in the form of 2x6's and 2x4's it lasts a long time without corrosion. So, I wouldn't worry about buying pressure treaed.

[grue]

I used cedar 2x4s to make mine... Not sure about up there, but they run only about $6 for a 2x4x8' board at the local Lowes here. I also found larger dimensions to be extremely pricey, but several 2x4s stacked together with ripped down 2x2 posts in the corners and about every 4' worked out well and weren't THAT bad on the wallet.

An episode of Ask This Old House the other day had a comparison of various wood options for raised bed gardens and mention was made of a product called TimberSil, which is essentially a pine board treated with glass (liquid glass is forced in and baked solid so it surrounds the wood fibers). Did a little bit of Googling, and it seems to have garnered a bunch of praise including some kind of award from Popular Science. The show claimed it's cheaper than regular treated wood, but I didn't find anywhere that had prices to compare myself (my search was far from exhaustive). This might be something worth looking into.

[bflocat]

Thanks for the suggestions! We looked into the "safe" chemicals used to treat the wood (ACQ), but I just didn't feel I could trust it. But we actually just found a bunch of ancient cedar railroad ties behind a friend's warehouse, so we'll be using those.

[mooseantlers]

I do a somewhat of a freebie.

Our property has an over abundance of white (paper) birch trees. I've taken a few down that were appropriately proportioned (thickness wise). If the tree has a bend, remove it! If the resulting log is too heavy to move, cut it & then join them together with metal straps and a few nails. Joined areas don't fit exactly but that's okay; with the strap in place to hold them together, I use a piece of landscaping mat & that keeps the soil in place. I've also used smaller saplings (again, white birch), nailed together in whatever I want and placed them around different plants.

I've been told that isn't the best idea; as the wood decays, it may attract ants. So far that's not been a problem. The pieces last 3-5 years and can be replaced whenever. And if you used galvanized straps, they can be reused.

It's just something that works for us, gives it a natural look and is easily replaced (white birch grows quickly).

[opabinia51]

Wow moose that's great!

[doccat5]

Moose, would you please provide some pictures? That sounds just great!

[mooseantlers]

Er . . I'm kind of embarrassed to admit this, the area is undergoing a 'rehab' So I can't post a photo. Will do so when it get finished (whenever that will be). The logs that were in place were due for replacement anyway!

[doccat5]

That's ok.........understand rehab.......LOL Post when you can, please

[honeychrome]

bflocat-
A little late for a response, but I'm surprised nobody mentioned Black Locust. It is an under appreciated species with a natural preservative, long used by farmers for fence posts, pole-barn posts, etc. It will outlast treated lumber and personally I don't believe the assurances that ACQ and CCA treated lumber is 'safe.' You should be able to find it in Western NY- I know there is a mill near Ithaca that specializes in it who last quoted me $2 a board-foot. A bit expensive, but if it will last 30-40 years its worth the investment.

As an aside, Black Locust is a really interesting tree- fast growing, very hard and strong wood, very high energy content for firewood, grows well on disturbed sites and fixes nitrogen. It can spread rhizomatically, which has given it a 'bad' reputation in suburban settings.

[hendi_alex]

I just constructed some raised beds and made them from whatever pressure treated lumber that is carried at Lowes. I line the inside of the frame with black plastic so that the soil does not come in direct contact with the lumber. I also considered buying some of that concrete siding material and was going to sandwich 3-4 mil plast between the concrete board and the treated lumber. Decided that was over kill though and simply opted for the plastic liner. If I were 20 years old, perhaps would have used the second method. But at 58, and little likelihood of any significant contamination, it would seem to me that any health related risk is on the extremely negligible end of the scale.

[smokensqueal]

I did something similar to hendi. I did a bunch of research since our local lumber store didn't really carry anything other then standard boards and pressure treated. I found out that the old pressure treated I belive is CCA is REALLY bad stuff and should never come in contact with dirt used to grow food. The ACQ stuff is suppose to be much better and not as bad. Chemicals are still chemicals though and even though they did some test and over a few year very mimimal leaked out into the soil and they said the plant's next to the boards showed no sigh of chemicals I still used plastic to coat the inside of my bed. I also read in some EPA document that they suggest using this for raised vegitable beds if you are on contaminated soil. They had a contact on the document so I sent them an e-mail stating what I was going to do and he also agreed that a plastic lining would be good idea.

I'm amazed to find out how may people use railroad tie. It was my understanding during my research that those are one things you really don't want to use because of all the oil products and chemicals they use in those.