I work for a non-profit senior's housing society. We have 48 slightly-raised garden plots and are contemplating what to use for re-doing the wood. Rona suggested 3 1/2" x 3 1/2" garden ties = $5.77 2"x6" pressure treated = $6.43 2"x8" pressure treated = $9.03 Pressure treated wood seems to be inappropriate due to the chemicals, but plain wood is not going to last long. We want an inexpensive solution. I've looked at the blogs and I'm wondering if the pressure treated wood has improved?
I use the common mini ties about 3.5 by 3.5 by 8 feet, and hold them in place with 2 foot rebar. I usually use two layers one on top of each other. Here are pictures of a recent addition to one of my garden beds. http://www.durgan.org/ShortURL/?TNKZN 26 September 2008 Completing New Garden Bed Mini ties have been installed to have support walls for the raised bed. Total time one hour. In the past I have used pressure treated wood, and railway ties with creosote and never had any detrimental effects on the plants. Here is another item that i have used, but I cannot find a supplier of the posts. http://www.durgan.org/ShortURL/?LXWIS 2 October 2008 Recycled Plastic Fence Post A friend had a number of these recycled plastic composite fence posts, and donated them to me for containing a garden bed. They are held in place with two foot, iron, half inch diameter, rebar through holes drilled in the posts.The black posts are 5 inches in diameter, and 8 feet long. The posts are easy to hand saw, and are about the same weight as two mini ties of the same length. I know nothing about the cost, or even where to purchase them at this time. I have been using wooden mini ties, but these fence posts would appear to be a fine replacement, since they will not deteriorate over time. The black colour also is not as obtrusive to the view, since it fades into the dark soil.
I would see if there is someone with a small saw-mill cutting cedar 2'" x 8' full measure, as the treated wood of today leaches chemicals quite badly, and causes infections if you get a sliver. You do not need construction approved grade for what you are going to do. Hope this helps.
Staple roofing paper or similar onto outsides of wood to create barrier between treatment chemicals and users.
Western red cedar locally milled is your best bet. A lot of the guys with portable sawmills often can offer you a good deal on "garden grade" wood that will be fine for what you are doing but is just not premium enough for fine woodworking. being in Burnaby you might have to try outside of the city. I personally Don't use pressure treated any where on my property but that is just my choice.
Alternatively, use the inexpensive cement block that either interlock or pour mortar, this will last far ages, no rot and no chemical leaching from creosote or other treated wood.
