How Do You Kill Bugs In Firewood?


Nobody wants to deal with bug infested firewood. They destroy your wood and they’re just plain nasty, but can you get rid of them? How do you kill bugs in firewood?

Use boric acid based insecticides to kill bugs that have infested your firewood. Unlike other insecticides, boric acid is safe to burn. Plus it’s completely non-toxic to humans and pets. Spray the boric acid solution on your firewood, let the bugs go back to infect their colony, and 1-2 days later they should all be dead.

If boric acid is such a good insecticide why haven’t I heard of it? It’s probably because it’s a few dollars more expensive than traditional insecticides like Home Defense, which is toxic when burned. Keep reading to find out how to spray your wood to kill bugs and prevent bugs in the first place.

Killing Bugs In Firewood

Killing bugs in firewood isn’t all that difficult, but you need to think about why the bugs are in your wood in the first place. Was the tree already infested with ants/termites? Or did they invade your firewood after the cutting/splitting process.

If the answers after cutting/splitting the wood you need to re-evaluate your stacking and seasoning method. There’s probably too much water in the wood which will slow down the seasoning process and cause the wood to rot. I’ll go over the proper seasoning process at the bottom of this post, but lets get into how you can kill the bugs that have already invaded your firewood.

Preventing bugs is always the recommended step, but killing them isn’t that hard either. There are 2 primary ways to kill bugs that have infested firewood. The most common method would be to use traditional insecticides like Home Defense which is toxic to burn but it comes in a big bottle and it’s easier to use. Personally, I wouldn’t burn traditional insecticides in an indoor fireplace.

The safer method would be to use Boric Acid Based Roach and Ant Killer (my favorite brand). Boric Acid based bug killers are more expensive, but they’re not toxic to humans. You can actually use boric acid powder as a chemical disinfectant to clean up your kitchen counters. I would spend the extra $5 and go with this approach.

Use Borax Powder To Kill Termites and Ants

Borax is a naturally-occuring water soluble powder that’s very similar to salt. It’s non-toxic to humans and pets, but kills wood-boring bugs/insects like carpenter ants, termites, beetles, etc. You can actually eat borax since it’s about as toxic as salt, but boy does it taste nasty.

Another benefit is borax kills all the microorganisms that cause rot and decay. So you’ll both kill all the bugs and preserve the useful life of your firewood. Think about what got you into this situation. It’s probably because your wood wasn’t properly stacked/covered. The wood got water logged, started to rot, and that brought in the bugs.

So how do you use borax to kill bugs? It’s actually really easy! Buy a bottle of your favorite borax spray (I like this one) and spray it all over the infested wood. You can also use borax cleaning powder, but you’ll have to mix it up in a water solution first and you have to get the amount just right.

Your goal is to spray the boric acid solution on the infested area so it coats the bugs exoskeleton. You don’t want it to kill them right away. They need to walk back to their colony, infect the food supply, to kill the queen. A few days later all the bugs will be dead and you can burn the wood as usual. If you screw up the concentration mixing your own solution it will kill them before they make it back to the colony

Is Borax Safe To Burn?

Borax powder not only kills bugs, but it’s perfectly safe to burn. Boric-acid may be sold as a roach killer or disinfectant, but it’s chemicals have a low toxicity to humans. I still wouldn’t recommend sticking your hands in borax, because it can cause burns.

There’s one really cool thing about burning borax covered wood. It actually burns with a green flame when you light it on fire. That always causes a few confused questions from my guests!

Can I Use Bleach To Kill Bugs? (Not Really)

Technically, you can kill bugs in wood using bleach, but it’s not practical. You would have to completely soak the log in a bleach bath for 24 hours. It would kill the bugs, but nobodies got time for that.

Some people swear by spraying bleach on their logs to get rid of ants, but there’s better stuff for that. Spraying them down with ammonia (cheap window cleaner works) is a much better solution. Ammonia will drive ants away and prevent them from getting onto the wood, but it will only kill a smell percentage of the colony.

So stick to borax if your logs are already infested. I prefer the Zap-A-Roach Boric Acid brand but they should all work the same. Boric acid powder will be harder to use, but it also works as a great all purpose cleaner. Plus it’s gonna keep ants out of your kitchen if that’s how you clean the counters.

Can You Spray Insecticide On Firewood To Kill Bugs?

As I mentioned above you can use insecticide on firewood, but it’s not recommended. Most insecticides are somewhat toxic to humans when they burn. Occasionally burning insecticides isn’t that big of a deal, but it’s still not recommended. Go buy a bottle of boric acid based insecticides if you plan on burning the wood.

Keeping Bugs Out Of Your Wood

Some trees are infested with ants and termites even before they come down. There’s really nothing you can do in that situation. Buy a boric acid based insecticide and go to town on your wood pile. Bugs that infest wood after the splitting/stacking process are usually the result of improper storage that leads to excessive moisture and rot. To make matters worse, the wood won’t fully season and it’ll burn like hot garbage.

So how do you properly season firewood to prevent bug infestations? If you follow four key steps you won’t have to worry about bugs and water damage. Keep the wood elevated off the ground, cover it up, allow proper airflow, and try to maximize sunlight. Your wood shouldn’t rot if you can provide all four of those things.

  • Raise Your Wood Off Ground: Buy/build a firewood rack to get your wood off the ground, improving airflow, and reducing the chance of getting bugs. You can go with pallets, but I really like those firewood rack brackets(I use these ones) that you use with pressure treated 2x4s. They’re cheap and it takes less than 5 minutes to screw a rack together.
  • Cover It Up: Cover up the top of your wood pile using a tarp or dedicated firewood cover. I bought a REDCAMP Firewood Cover a few years ago and I really like it. Being able to zip/unzip the sides is so much easier than screwing around with a tarp. I’ve found that I’m way more likely to make a fire since it’s less of a hassle.
  • Improve Airflow: Raising your wood off the ground provides some airflow, but you need to leave the sides of your wood pile exposed as well. A little bit of rain isn’t going to damage your firewood. All it takes is 2-3 days of sunshine to dry out a rain soaked wood pile (assuming the wood is seasoned). Check out my post explaining how to burn wet wood.
  • Maximize Sunlight: The sun is the most powerful heat source on the planet. So your wood should dry faster if you work on increasing the amount of sunlight it receives. Dry wood means you won’t have to deal with bugs and rot.

You won’t have to worry about bugs if you follow the above directions and keep your wood dry. Plus properly seasoned wood will be easier to light, burn better, and smoke less. There really is no downside to using a firewood rack.

If you need to save money head down to your local grocery store dumpster to grab free pallets and cover the wood with a cheap 6×8 tarp. There’s really no excuse for letting your wood get wet and rot.

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