How to Prevent Wood from Rotting in the Ground (Full Guide)

Whether you are installing a new fence or simply have a wooden stake that you’d like to keep in the ground year-round, preventing your wood from rotting can be a difficult task. So, how can you prevent wood from rotting in the ground?

Choose a reliable type of wood, such as pressure treated, and be sure to treat your wood with specific compounds that prevent decay. Sealing the wood is the best way to prevent wood from rotting while in soil. Installing posts into concrete can also prevent wood from rotting while in the ground.

But what exactly causes wood to rot while it is in the ground? And why does using treated wood matter so much? Let’s answer some of your questions now!

What Causes Wood to Rot in the Ground?

The main cause of wood rot when you place it into the ground? Moisture.

There’s no possible way to avoid moisture in soil or ground cover. You may have wood that lasts longer when placed in the ground in a dry and drought condition area. However, there is always moisture present, whether we can sense it or not.

When a piece of wood gets wet, it becomes a breeding ground for mold, contaminants, and other factors of decay. When paired with dark underground conditions and heat, you will no doubt have rotting wood on your hands in no time!

This can be especially discouraging if you live in a damp environment, especially a location that experiences a lot of snow or rain. There is hope however- choose the right wood, and the right wood treatments!

Does the Wood Type I Choose Matter?

It may surprise you, but the type of wood that you choose for your outdoor project matters. You’ll want to keep an eye out for very specific types and treatments. Here are some reliable choices of wood for placing into the ground.

  • Cedar is known for its pest resistance, especially with certain bugs and moths. It is a relatively affordable and soft wood, making it useful for a variety of applications. 
  • Redwood is a very popular choice for outdoor uses, as it has a lot of natural rot resistance. It is also structurally very strong, making it good for fences and structures.
  • Cypress is a beautiful light wood that is very stable and resistant to rot. It is more expensive than other options, but it can be used in the ground without issue.
  • Pine comes in many varieties and forms, but it can be a pest-resistant and decay-resistant wood. However, given the sappy and soft nature of pine, you should choose this type of wood carefully.
  • Pressure-treated wood is often the way to go for sticking wood into the ground. It is made to resist erosion and decay, though it may need further sealing before it is ready to go into the ground.
  • Other treated woods are recommended for use in the ground, especially those treated with decay-resistant chemicals. You can buy treated woods, or simply treat it yourself!

The Importance of Using Treated Wood

Since I have already mentioned treated wood as a popular type for use in the ground, you may be wondering why it might be so important to use treated wood.

Treated wood is essentially any type of wood that has been chemically sealed or treated to resist mold, mildew, and other forms of rot. You are doing yourself a disservice if you place untreated wood into the ground. While it will last for a brief time, it will decay far faster than treated wood.

Finding a chemical treatment for your wood is possible, and you may even find pre-treated cuts of lumber. If you plan on treating it yourself, there are even more options for you- but more on that later!

Staying Away from Soil – Set the Wood in Gravel and Concrete

Are you worried about rot and what soil can do to your wood in the first place? Maybe you should consider placing your wood in gravel or concrete instead! This option is most popular for fence and decking installations since the wood is away from moisture found in the ground.

Whether you have a building vision in mind or are having your fence professionally installed, choosing to pour concrete or use gravel to anchor your wooden fence posts can be an easy enough solution. The extra labor may be more than you were expecting, along with the extra fees for concrete or rock.

However, if you live in a particularly damp location and want your wood to last as long as possible, choosing this method of installation may prove worthwhile for you. No matter what, you will still want to use treated wood! Let’s learn more about that together.

Furthermore, installing fence posts and decking into concrete will produce a much stronger foundation for your outdoor structure.

Can I Place Pressure Treated Lumber Directly in the Ground?

Pressure-treated lumber can be a great choice for your next outdoor project. However, can you place this type of wood directly into the ground? 

Having pressure-treated wood essentially means that you are dealing with a type of softwood pine. This pine is already naturally resistant to termites, pests, and some forms of decay. However, this does not necessarily mean it will resist moisture and decaying properties found in soil.

You will need to keep an eye out for pressure-treated lumber, but specifically, pressure-treated lumber marked for ground use. There are usually two types of pressure-treated wood, rated based on their ability to withstand in-ground decay.

You will want to choose ground-safe lumber, no matter if it is pressure treated or not. Thankfully, hardware stores make this easy for you to determine with labels and hands-on knowledge. If you aren’t sure about the type of wood you should be buying, ask your local hardware professional!

Ways You Can Treat Wood Yourself

If you have your lumber selected for your project, now is the time to make sure it is properly sealed before placing it in the ground. If you purchased untreated wood, how can you treat it yourself to best ensure that your wood will resist decay?

First, you need to purchase an excellent wood treatment. I recommend the following products for treating your lumber. Always be sure to follow the treatment instructions from the manufacturer before getting started!

SEAL-ONCE MARINE – 1 Gallon Penetrating Wood Sealer, Waterproofer & Stain

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SEAL-ONCE has been leading the innovation in the use of nanotechnology to create long-lasting, Eco-safe wood sealers, waterproofing and tinted wood stains since 2005. This exclusive MARINE formula is made for use on wood in high-moisture environments near ponds, lakes, rivers and oceans. 

Unlike moist top-coat sealers that trap water vapor below the surface, MARINE uses proprietary nanotechnology to penetrate beneath the surface of wood, coating the wood fibers at the cellular level. MARINE forms a flexible, breathable barrier that allows the wood to expand and contract. 

MARINE allows wood to age naturally without decay, and can be used to preserve old or new wood, extending its natural life. It is non-film forming and will not alter the natural beauty of the wood. The tinted wood stains provide additional UV protection from harmful UV sunlight.

Rust-Oleum 1904A Wolman (Woodlife) CopperCoat Green Wood Preservative

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Looking to use non-pressure treated wood for your next outdoor project? Check out this product from Rust-Oleum, the outdoor preservation leader for many materials! If you have a beautiful piece of unaltered lumber that you would like to preserve before putting it in the ground, check out this product.

Protect and preserve below-ground exterior wood with Rust-Oleum Wolman WOODLIFE CopperCoat Green Wood Preservative. This unique formula contains an insecticide and nearly double the fungicide of standard sealers or stains. It’s paintable and stainable as well, making it a versatile product.

The insecticidal preservative prohibits termite damage, rot and decay. This product also inhibits surface growth of fungal organisms such as mold, mildew and staining fungi. While it imparts a transparent green color at first, this stain naturally fades over time. It is a great choice for your next project.

LinSheen Boiled Linseed Oil

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Looking for a more natural option for preserving your outdoor wood? Check out Linseed oil- while it is flammable and toxic and shouldn’t be used with any eating surfaces, it may be a great natural sealer for your outdoor fence or deck!

This boiled Linseed wood refinishing oil absorbs into the wood’s grain, enhancing the natural color and the texture of the grain. This makes it a great choice for your lumber, both in the ground and above it! Why not enhance the natural beauty of the wood you’ve purchased?

It is a fast-drying wood oil that penetrates deep into the grain to help condition the wood, restore the wood, and ensures its longevity. It also has drying solvents added to the oil to speed up the drying process!

How to Treat Your Wood for In-ground Contact

Now that you have some idea of the preservatives involved in treating your in-ground lumber, it’s time to actually treat these pieces!

While every product has a different application process, it is recommended that you treat your lumber in the preservative for roughly half an hour before moving forward. Let whatever section that is going into the ground soak, and apply a full coat of the preservative to the rest of your lumber.

Allow your pieces of wood to dry thoroughly overnight, or longer if they are still tacky or damp to the touch. Once all of your wood is dry, feel free to place it into the soil and begin building your project!

No matter the application, these products will prevent decay as well as bring out the natural beauty of your wood project. You can even tint or paint over these many options as well- the sky’s the limit now that your wood won’t rot in the ground!

Final Thoughts

Finding a reliable and decay-resistant wood for use outdoors can be difficult. However, there are many options, once you know and understand the importance of treated wood. You can build your next fence or wooden project with some peace of mind!

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