If you buy a wooden planter from heat treated wood it is “tantalized”, it will protect it for around 10 years. We advise you when you are using wooden planters in your garden, or any other wooden products, use one of the outdoor wooden type finishes available from garden suppliers. You can buy some products that protect your wood against rot, fungal and insects, some products even protect wood against UV light.

Danish oil and linseed oil

You can use Danish Oil which is a great wood finish and similar to linseed oil. The advantage of Danish oil above linseed oil is that it dries much quicker. A disadvantage is that you have to be careful with to not get it on your skin. Using Danish oil is presumable nowhere near as bad as the toxic chemical wood preservers you can buy on the market. Another thing you can do is treating your hardwood wooden planters with teak oil. The only disadvantage is that you have to do this annually.

Use this recipe from the Vegetable Gardener’s Bible (Amazon.com):

• 1/2 cup linseed oil
• 1 oz melted paraffin in 3 1/2 quarts of turpentine

For those who don’t know this book it is highly recommended and it is written by Ed Smith, an experienced vegetable gardener from Vermont. He has put together this amazingly comprehensive and commonsensical manual, The Vegetable Gardener’s Bible. Basically, Ed and his family have been growing a wide variety of vegetables for years and he’s figured out what works. This book, filled with step-by-step info and color photos, breaks it all down for you.