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msgeoghegan
Raised garden bed - Pressure treated lumber.
msgeoghegan

Have to rebuild our raised garden beds and wanted to know any pros/cons of using pressure treated lumber? Also, if I do use it, are there precautions to take to prevent contaminating the garden produce? Thanks!

A. Spruce
Re: Raised garden bed - Pressure treated lumber.
A. Spruce

DO NOT use pressure treated lumber for food beds, as the chemicals within the lumber will leach into the soil and plants. Use a naturally rot resistant wood, such as redwood or cedar, any wood high in tannins will do. Make sure that the material is heart wood (mature wood ) and not sap wood (still growing wood ), as the sap wood is not bug/rot resistant. The easiest way to explain this is by using redwood as the example. Redwood is named due to its color, the mature wood is red. Low grades of redwood will be riddled with white, the white is the sap wood. Go to Home Depot and look at the pile, you'll see that every stick is nearly all white, with scant traces of red, this material is garbage and will rot quickly if in contact with the ground. A good lumber yard will carry a better grade of redwood, wood that is mostly, if not all, red in color.

keith3267
Re: Raised garden bed - Pressure treated lumber.
keith3267

When you compare the cost of plain old pine to the cost of the naturally resistant woods, you can rebuild the beds several times over using the pine and be money ahead.

You can also use plane pine and paint it with a non toxic paint or stain and it will last longer.

A. Spruce
Re: Raised garden bed - Pressure treated lumber.
A. Spruce
keith3267 wrote:

When you compare the cost of plain old pine to the cost of the naturally resistant woods, you can rebuild the beds several times over using the pine and be money ahead.

You can also use plane pine and paint it with a non toxic paint or stain and it will last longer.

Good point, I built some beds out of fir about 8 years ago and just now had to replace them. In my area, redwood is plentiful and lasts about the same length of time. Case in point, when I built the beds I also installed a redwood fence, the fence posts rotted off before the beds disintegrated.

Sombreuil_mongrel
Re: Raised garden bed - Pressure treated lumber.
Sombreuil_mongrel

Since they took the arsenic out of lumber treatment I feel better about it. It still contains copper. IDK how much copper leaches into the soil, nor how much plants will take up copper and store it in the parts we eat. We eat stuff cooked in copper pots, so it can't be that bad.
Casey

dj1
Re: Raised garden bed - Pressure treated lumber.
dj1

I use 1x6 fencing boards (redwood or cedar), secured by redwood/cedar stakes. Then replace them as needed, sometimes 10 years.

keith3267
Re: Raised garden bed - Pressure treated lumber.
keith3267

The city lot has ground up wood chips from tree trimming and such. I get it for $10/yard and make my raised beds from it. I put it about 4 to 6" thick, 2' wide in the pathways and perimeter of the beds. The beds are 4' wide and filled with manure and old leaves. Very easy to build up as needed.

ordjen
Re: Raised garden bed - Pressure treated lumber.
ordjen

I have no problem with pressure treated lumber for raised beds, so long as the inside of that lumber is lined with heavy 6 mill plastic. Line the inner sides, staple the plastic to the top of the lumber and then put a decorative strip over the top edge to hide the staples and give a nicer look.

The same plastic lining is not a bad idea with any type of lumber. When it comes to rot, nothing is worse then holding wood constantly wet. After all, you are watering this garden almost daily! Worse yet is that the water contains organic matter from the siol. Rot is fungus feeding off the cellulose in the wood. Water and organic matter invites rot in the most rot resistant woods. I have never seen a rotten cedar fence other than where the owner has allowed the boards to touch the ground, Once again, water and organic matter. Bad combination!

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