How To Safely Treat Wood Used for Raised Garden Beds

The most common and simplest way to build a raised garden bed is with lumber. However, you may want to avoid using any wood that has been treated with harsh chemicals that can leach into the soil. The problem is that untreated wood doesn’t last nearly as long for garden beds as treated wood.

Wood Raised Bed Garden

Treating wood using organic techniques is always the best method to avoid the severe damage that inorganic chemicals can cause to your garden’s soil and the ecosystem. These harsh chemicals can cause problems for insects and fungi present in the ground that aid in decomposition and harm the soil food web. So how do you treat wood appropriately?

Different Methods For Treating Wood Safely

Linseed Oil

Linseed oil is a byproduct of flax seeds, and it’s a common outdoor wood preservative. The oil completely covers and soaks deep into the wood preventing water from seeping through. As we are well aware, water is the main reason why wood rots and decomposes very fast. Despite the various drawbacks that come with using this byproduct, it is organic. It poses more minor threats and damage to the environment than inorganic chemicals.

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Last update on 2024-06-13 / Affiliate links / Images from Amazon Product Advertising API

How to use it

First things first, you must understand that the tools used in applying linseed oil can combust, so it’s safe to wear protective clothing while applying linseed oil and dispose of the tools properly.

Applying the linseed oil is pretty straightforward. Using a brush, keep spreading the oil until the wood can no longer absorb any more of the oil. You can also use a rag that doesn’t have such an absorbent material so as to leave most of the oil on the wood. Allow the oil to seep into the wood, and once it starts dripping, the wood has fully absorbed the oil.

Some of the drawbacks of using linseed oil are

It takes a long time to dry. So if you’re planning to use the wood during winter, make sure to apply the oil during summer to give the wood ample time to absorb the oil and dry. It might also take longer than just the summer season to let it dry, so plan earlier to avoid getting inconvenienced.

The oil provides no UV light resistance. Eventually, your wood will turn grey due to sunlight.

The oil is an organic byproduct of flax seeds, making it very biodegradable. It’s crucial that you reapply at least once every year just to maintain the wood’s oil capacity to avoid water from seeping in.

Shou Sugi Ban (Charring Wood)

Shou Sugi Ban is a method of wood preservation that initially originated from Japan and was used to treat wood by charring the wood through fire. The wood is passed through fire to burn the surface and scorch it. After that, it’s allowed to cool down before any natural oils are applied to the surface. This method was mainly used on Japanese cedars found in the region.

The wood would then be immune to any attacks from fungi or the sun or water. This process may be used as art or a preservative method. Whichever way you look at it, the process came in handy either way.

Shou Sugi Ban

Treating wood in this way is extremely effective against the decomposition of the wood due to insect damage, and fungus growth and even protects the wood from UV rays. The wood will also maintain it’s color and not fade due to weather and sunlight with this method.

Tung Oil

This is a great alternative to linseed oil as it dries up, ultimately making it water-resistant. It’s a byproduct of the Tung tree found in China and other Asian countries. Its versatility makes it popular among carpenters as it’s easy to use, provides that perfect finish, and is very environmentally friendly.

Benefits of using Tung oil include

  1. The product is food safe hence making it easy to use around your garden.
  2. Tung oil is very durable, so you don’t have to keep reapplying.
  3. It has a finishing that doesn’t mold or go rancid after being used for long.
  4. The oil doesn’t take very long to dry, so you can apply it any time without worrying about it taking up a lot of time to dry.

Pure Tung oil versus dark Tung oil.

Watch out for these two. If you don’t have an experienced eye when it comes to using both, you just might easily mistake one for the other. But as the name suggests, pure Tung oil has zero additives and has no glossy finish once applied. At the same time, dark Tung oil has additives such as PCB-free hydrocarbon, which is also non-carcinogenic, just to give the oil that rich dark look after it is applied to the wood surface.

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Last update on 2024-06-13 / Affiliate links / Images from Amazon Product Advertising API

How to apply

You’ll need to approximate how much wood surface you’ll need to cover with the oil. Depending on how large your garden is, you just might need several gallons of oil.

Make sure all wood surface is clean and ready for application. If the wood needs sandpaper to smoothen the surface, then you can work on that as well. Using sandpaper also eliminates any previous coating present on the wood.

Always choose an oil that has already been thinned out. This makes it easy to apply. However, depending on the type of wood surface you have, consider the thickness of oil needed. Weathered wood or old surfaces may require thicker oil concentrations compared to fresh wood surfaces.

The process of coating the surface with the required amount of oil may be lengthy. That is because you have to wait until the wood is fully absorbent of the oil and well-saturated. For functionality, apply the oil in about five layers to allow the oil’s durability on the surface.

Allow the oil to dry in the shade for the next thirty days, preferably or under shelter. Don’t disturb the wood surface while it dries and allow the oil to fully absorb oil. Get rid of any excess oil that might be dripping from the wood surface.

Once the wood has fully absorbed the oil and dried, you may now proceed to use the wood for whichever purpose you had in mind. In the dried state, Tung oil is durable, has a plastic look and feel, and can protect the wood from sunlight and humidity.

Eco Wood Treatment

This preservative works by seeping through the wood surface to create a natural membrane against water and fungal growth that eventually lead to the wood rotting. Once applied, it takes a mere couple of hours to give the wood surface that shiny look while creating a durable surface. It has many benefits, as indicated below.

  1. It is safe to use around people and plants, so you’re sure the ecosystem in your garden will not be affected.
  2. It is a non-toxic wood preservative.
  3. The product comes in dry powder, which allows you to dilute to the concentration that you prefer.
  4. Eco wood preservative can be used once and doesn’t need one to reapply the product repeatedly.
  5. The product also has a long shelf life and will go a long way even for future use.
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Last update on 2024-06-13 / Affiliate links / Images from Amazon Product Advertising API

How to use

Simply mix the dry powder and the recommended amount of water to make a liquid mixture. Proceed to apply the mixture on the wood surface as much as needed. Suppose you have a lot of wood surfaces to cover. In that case, you can also consider using a tank sprayer to apply quickly and efficiently without the hustle of worrying about the labor.

LifeTime Wood Treatment

This is a preservative that, although it’s manufactured, it’s very organic and environmentally safe. The product can be used anywhere in your garden, on the wood used to build playhouses for your children, and so forth. The product does no harm to the insects or beneficial micro-organisms in your garden, thus not affecting your plants.

Compared to other natural products used in preserving wood, this particular product requires no maintenance as it enhances the natural appearance of the wood surface while still being very durable. You can easily apply it to the wood surface. It doesn’t require numerous amounts of coating to establish its usefulness to the wood.

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Last update on 2024-06-13 / Affiliate links / Images from Amazon Product Advertising API

How to apply

Once you’ve applied the product to the wood, allow it to dry for the next 48 hours before spraying water to make it even more durable. More sunlight and water exposure will enhance the color effect on the wood and give it a more lovely patina color. With time, the color will deepen and vary between the deep silver-grey color and dark brown color.

To use, simply dilute the powder with water and make a liquid concentration making it easy to apply. It’s important to note that the particles may not completely dissolve. Still, it doesn’t mean the product’s efficiency has been watered down.

To apply the product, you may choose to use a brush or spray the surface depending on the amount of surface you have to cover. If you’re using a spray, remember to strain the particles from the liquid to make the application process seamless and smooth.

For good results, ensure that all surfaces are covered by the product, including any cracks or open cuts the wood surface might have. You should also cover the end parts of the wood. This will give you maximum results.

Overtime. The results should start being visible. Don’t worry if some wood surfaces don’t react immediately to the product. Sunlight and humidity should bring out the results as time goes by, making the color of the wood deepen, as mentioned earlier.

When handling this product, keep all powdery forms of it away from any plants or insects and handle it wearing protective clothing as it is very acidic. However, once diluted, the product is basically harmless.

Timber Pro UV

This preservative is a non-toxic product that naturally reacts with the alkaline present in wood to create a waterproof membrane, thus preventing any water particles from sipping through the wood. It’s perfect for garden use and, more significantly, livestock farming when building chicken coops and so much more.

The application method is quite simple as you only need to mix with water to achieve a consistency that allows you to easily apply the wood surface. The best tool is the paintbrush which allows for great coverage on the surface and excellent consistency.

Find out more about this product and where to get it at


Preserving wood in your garden can be used for various uses such as raised garden beds, fencing, livestock fencing and troughs, flooring, and any other use you might have around your home. What’s important is making sure that whichever method you use as treatment is environmental-friendly, safe to use, and easy to apply on the wood surface.


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    Author, blogger, podcaster, homesteading and permaculture enthusiast. I have a passion for sharing what I learn and helping others on their journey. If you're looking for me, you'll usually find me in the garden.

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