When building a grape arbor are there any types of pressure-treated wood that are considered safe near the roots of the plant?
I will be replacing an old existing grape arbor with a new wooden arbor. There are many types of pressure-treated wood, such as...
Chromated Copper Arsenate (CCA-C),
Alkaline Copper Quat (ACQ-C, ACQ-D, ACQ-D Carbonate),
Micronized Copper Quat (MCQ),
Copper Azole (CBA-A & CA-B) and
Sodium Borates (SBX/DOT)
Are any of these safe and nontoxic near the roots of a mature grape vine? It seems that the more rot-resistant species of wood (such as cedar) can be expensive; are there any practical low-cost alternatives?
A naturally rot-resistant wood will certainly be your best choice.
Cedar, cypress, or locust are great choices.
Instead of shopping the local home-improvement stores, look a little further for a local sawmill, timber supplier, or even a timber frame company that can supply hefty timbers that are treatment-free and will stand the test of time. You may find them more economical than the treated wood.