Using Beeswax to Make a Natural Wood Preservative

A Non-Toxic Alternative to Pressure Treated and Stained Lumber

For years I was building raised beds and compost bins and feeling stuck with two less than ideal choices when it came to wood preservative: use pressure treated lumber, stains, or paint and risk soil contamination, or use nothing and know that the wood wouldn’t last as long. The reason to use stains, paint, or pressure treated lumber is that when wood is used outside and unprotected by a roof, moisture leads to rot via fungal decay and insect activity.

I knew from childhood that pressure treated wood was generally best to avoid. My father (a carpenter) would tell me not to play near the pressure treated deck posts because if I got a splinter, “that would be bad”. It’s not as bad as it used to be when it was made with arsenic, but pressure treated lumber is made by forcing a mixture of fungal and insect repellent chemicals into wood. These chemicals are generally considered harmful to humans if ingested, inhaled, or if they’re in contact with our food. The same is true for residues from most paints and stains. Not good for the garden. This was a challenge for building raised beds and compost bins. Food grows in soil that’s right up against the raised bed wood so it’s not desirable to have a chemical cocktail right there to leach out.

For many projects I used untreated cedar, which is naturally anti-fungal and insect-repellent. But it’s also a high demand, low supply wood making it costly and not always available. There had to be a way to preserve wood without a chemical dousing.

About a year ago I was reading Bioshelter Market Garden: A Permaculture Farm by Darrell Frey and came across a section about how lumber coated in beeswax was used for below ground applications. Bingo! Turned out this technique was not new. It had been used extensively before modern pressure treated lumber and wood preservatives arrived on the market, but it fell into relative obscurity as there modern alternatives were adopted.

raised beds freshly coated in a beeswax, turpentine, and linseed oil mixture

The beeswax preservative is made by mixing beeswax, linseed oil, and pine gum turpentine carefully over heat. I was skeptical about using turpentine so I looked into it and found that there are two general types: pine gum and mineral spirits. Pine gum turpentine is distilled from pine resin, is often a byproduct of pulp and timber industries (although can be tapped without harvesting the tree), and is wholly plant-based. Turpentine labeled as “mineral spirits” on the other hand are distilled from coal or petroleum, are fossil fuel based, and loaded with compounds best kept far, far away from your food. You want to use the pine gum turpentine here.

We use beeswax from Champlain Valley Apiaries in Middlebury, VT, but any beeswax will do. It took a few batches to get the mixture dialed. Too much beeswax and it accumulated on the outside of the wood making it waxy and slippery. Too little and there isn’t enough to protect the wood well. The key was getting the ratios just right so that all the beeswax was pulled into the wood grain by the turpentine, leaving none to form a film on the wood after. The linseed oil (also plant based made from the flax plant) is needed as an emulsifier to get the wax to mix with the turpentine. It also adds pleasant yellow color to the end result.

We offer the beeswax treatment as an option on our installation projects. It adds to the beauty of the project and its fantastic to no longer have to decide between pressure treated, stains, paints or untreated wood. The beeswax stain makes projects look gorgeous and last longer, but it also gives us the opportunity to support another local business (Champlain Valley Apiaries) which in turn supports the bees. And we all benefit from those for pollination of our flowers, fruits and veggies, and of course, for honey…sweet, sweet, honey…

trellis posts treated and being prepped for installation