Can you suggest an alternative to pressure-treated wood for garden borders and raised planters?

Asked by Phoebe Tureen

I live in Los Angeles. Can you suggest an alternative to pressure-treated wood for borders and raised planters in my garden?


Polly Osborne, FAIA, LEED AP

Answered by Polly Osborne, FAIA, LEED AP

Los Angeles, CA

Polly Osborne Architects

March 22, 2007

There are several recycled rubber and plastic garden borders on the market.

Raised planters

For raised planters, you can use recycled wood and plastic lumber as well as Forest Stewardship Council (FSC) certified lumber rated for use in contact with the ground.

  • Additionally, borate-treated lumber is a less toxic version of pressure-treated lumber.
  • There is also a sodium silicate-based treatment process for wood.
  • TimberSIL, a manufacturer of this technology, claims the treated wood is nontoxic, odorless and nonvolatile; is not corrosive to fasteners; does not cause excessive wear on tools; and has a natural color.

These are readily available at Los Angeles nurseries and some lumberyards.

Considering durability and aesthetics

It is important to visit local nurseries and lumberyards to find out which type of material is right for you, because the choice you make often is a matter of taste.

  • Aesthetically speaking, natural wood will be the best.
  • Durability-wise, plastic lumber is likely to outlast anything else.
  • One trick to make plastic lumber nicer looking is to use natural lumber to hide the ends of the plastic pieces.

Plastic lumber

Plastic lumber doesn’t look very nice with moss or dirt, as it tends to get splotchy, so you will occasionally want to wash down the planters.

Another thing to remember with plastic lumber is it bends more than wood, so you’ll want to have plenty of support. Of course, that is why it is perfect for your edging borders.


For more information:

The Environmentally Preferable Purchasing Guide

Plastic Lumber Trade Association

Sustainable Building Sourcebook

Tagged In: certified wood, plastic lumber

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