How to preserve wood in raised garden beds

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Raised garden beds are particularly effective in areas with poor soil conditions and drainage issues. They allow gardeners to plant early and avoid freezes. Many raised beds can help to eliminate attacks from burrowing creatures like moles and protect the garden from slugs and other insects. When making a raised garden bed from wood, you should buy pretreated planks or preserve the wood to avoid rotting. Many eco-sensitive gardeners prefer not to use chemically treated wood and find other, more natural ways to preserve their borders and beds.


Melt 28.4 g (1 oz) of paraffin wax in a double boiler. Add in a gallon of turpentine and 355 ml (1 1/2 cups) of linseed oil, mixing it together.

Dip small pieces of wood in the mixture and hold for three minutes. Double or triple the formula for longer pieces of wood and brush on the mixture.

Move the wood around from top to bottom every year to prolong its life. By decreasing the exposure of the pieces that sit on the ground, you can reduce rot and preserve the wood longer before having to replace it.

Consider using premade organic, nontoxic wood preservatives such as Lifetime Wood Treatment that is eco-friendly and contains no toxins that can seep into the soil.

Chemical treaments

Paint the timber with a wood preservative such as Cuprinol or Wolman's. These products are formulated to treat wood that is touching soil as well as add colour to the pieces. Most preservatives contain copper, which can leech into the ground and affect the taste of the vegetables, though they are officially considered safe. Preservatives that use arsenic and other toxic chemicals are banned and no longer sold.

Remove any bark from the wood and liberally apply the preservative to the entire piece. Let it dry completely before using the wood. Wood preservatives contain fungicides and insecticides that may affect an organic garden.

Line the inside of the garden bed with plastic to preserve wood longer and keep chemicals on treated wood from seeping into the soil. If you're building a raised garden bed up on posts that won't be resting on the ground, line the bottom of the bed as well as the sides.

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