Beyond their conventional use, the remnants of a wood-burning fireplace hold surprising potential. In fact, in the 1700s through the early 1900s, wood ash was used to produce potash (an alkaline potassium compound) for fertilizer and alkali before its value as a raw material declined. From enhancing soil quality to crafting natural cleaning solutions, we’re rediscovering just how versatile ashes can be around the house. Not all wood ash should be repurposed, however: Avoid using wood ashes from painted, chemically treated, or stained wood as they can contain harmful substances that can harm plants and soil if they’re used in the garden. The safest wood ashes for repurposing come from untreated, natural wood that has not been processed or chemically treated.
I’ve always been amazed at how something as simple as wood ash can have so many uses. Back when I was helping my dad clean out our old fireplace, we’d just toss the ashes without a second thought. Now, learning about their potential, I wish we’d saved some! A quick tip: always double-check that your ash comes from untreated wood. I once made the mistake of using ashes from some old painted boards, and let’s just say my garden wasn’t too happy about it. If you’re unsure, a local nursery can often test your ash for contaminants to keep your plants safe.
1. Compost Them
There’s a reason gardeners call compost “black gold”: It’s a gold mine of nutrition for your plants. Adding wood ash to your compost both recycles waste and boosts the potassium level of your compost. Add a thin sprinkle of untreated wood ash over the organic matter in your compost pile, and you can look forward to hearty plant growth when you spread that compost in your garden.
Adding wood ash to compost is one of those tricks that feels like cheating nature. Potassium is a key nutrient for plants, helping with root development and disease resistance. In my own backyard, I’ve noticed my tomatoes and peppers thrive when I mix in a bit of ash with my compost. Just be careful not to overdo it—too much ash can make your compost too alkaline, which can mess with nutrient availability. A good rule of thumb is to use about a cup of ash per square foot of compost. If you’re curious about your compost’s pH, a simple soil test kit can keep you in the know.
2. Use Them as Ice Melt
It’s not a bad idea to keep a container of recycled fireplace ashes in your trunk in the winter. They can give your car traction on an icy patch of road, and the potassium salts in ashes can help melt snow in moderately cold conditions.
I learned this trick during a particularly brutal winter when my car got stuck on an icy driveway. A neighbor suggested sprinkling some fireplace ash under the tires, and it worked like a charm! The potassium salts in the ash lower the freezing point of water, similar to commercial ice melts, but it’s a lot cheaper. Just make sure the ash is cool before storing it in your car—you don’t want to accidentally start a fire. I keep a small bucket in my trunk from November to March, and it’s saved me more than once.
3. Raise Soil pH
If you have acidic soil, you can amend garden bed soil with wood ash to raise its pH. Because wood ash is about 70 percent calcium carbonate, it will do the same thing lime does, but it will work even more quickly because its particle size is so much smaller. Use the ash in moderation, of course, to avoid raising the pH too much—and be sure to test your soil regularly to check its levels.
Adjusting soil pH with wood ash is a game-changer for gardeners dealing with acidic soil, which is common in areas with heavy rainfall. I’ve used this method in my flower beds, and my hydrangeas went from struggling to blooming like crazy. The calcium carbonate in ash acts fast because it’s so fine, often showing results in weeks rather than months like lime. A soil test I did last spring showed my garden’s pH jumped from 5.5 to 6.5 with just a light application. Start with a small amount—maybe a half-pound per square yard—and retest after a month to avoid over-alkalizing.
4. Absorb Odors
Like baking soda, wood ash is alkaline, which means it will absorb moisture and odors from the air. Put a small bowl of remnants from last night’s firepit in your fridge or in a musty room, and it will freshen the space in a jif.
I’ve used this trick in my basement, which gets musty after heavy rain. A bowl of wood ash left in the corner for a couple of days made a noticeable difference—no more damp, funky smell. The alkalinity of ash neutralizes acidic odor molecules, much like baking soda, but it’s free if you’ve got a fireplace. Just swap out the ash every week or so to keep it effective, and don’t let it get wet, or you’ll have a pasty mess on your hands.
5. Clean Stains on the DrivewayYou can remove oil stains from your asphalt or concrete driveway using ashes from your fireplace. Sprinkle the ashes on top of a stain, let them sit for several hours to absorb the oil, then sweep the mess away with a broom.
This method saved my driveway after a car oil leak left an ugly stain. I sprinkled a generous layer of ash, let it sit overnight, and swept it away the next day—no scrubbing needed! The ash’s absorbent nature pulls oil out of porous surfaces like concrete. For stubborn stains, I’ve found letting the ash sit for a full 24 hours works best. If the stain persists, try mixing in a bit of dish soap with the ash to boost its grease-cutting power.
6. Control Slugs and Snails
Gardeners have long used ashes to deter slugs and snails from their veggie beds. Because wood ash is a natural desiccant, and the bodies of slugs and snails have such a high water content, the critters are loath to cross it. Ringing plants with a sprinkle of wood ash can keep these pests at bay.
Slugs were the bane of my lettuce patch until I tried this trick. A thin ring of ash around my plants stopped those slimy invaders in their tracks. The ash dehydrates their soft bodies, making it uncomfortable for them to cross. I reapply after rain since it washes away, but it’s a small price to pay for chemical-free pest control. Just be sparing—too much ash can mess with your soil’s balance, especially for acid-loving plants like blueberries.
7. Make Soap
When you mix wood ash with water, you get lye, which is a common ingredient in traditional soap-making. Mix in some fat and add a lot of boiling and stirring, and you’ve got homemade soap.
Making soap with wood ash feels like stepping back in time. I tried this once with a friend who’s into homesteading, and while it’s a bit of a process, the results were surprisingly good. The lye from ash is caustic, so you’ve got to be careful—gloves and goggles are a must. We used a ratio of about one part ash to five parts water, then mixed in rendered animal fat. After some serious stirring and boiling, we had a rustic bar of soap that worked great for cleaning dishes. If you’re new to this, start with a small batch to get the hang of it.
8. Polish Metal
Wood ash is a mild abrasive. Mixing it with a little water forms a paste you can use to polish silver and other metals. Dip a soft sponge or cloth into the ash and water mixture, then rub the paste on the silver item. Wipe off with a clean cloth.
I’ve used this on my grandmother’s old silverware, and it brought back the shine without harsh chemicals. The ash’s fine particles gently scrub away tarnish without scratching. I mix about two tablespoons of ash with a teaspoon of water to get a thick paste, then rub gently with a soft cloth. For heavily tarnished pieces, let the paste sit for a few minutes before wiping. It’s a cheap, eco-friendly way to keep your metals gleaming.
9. Slow Algae Growth
While wood ash won’t actually kill algae, ashes can help control it. Because wood ash is so high in potassium, sprinkling it into a pond will encourage the other plants to grow and compete with the algae, keeping it in check.
I’ve got a small pond in my backyard, and algae was a constant headache until I tried this. A light sprinkle of ash every few weeks keeps the water clearer by giving other plants a nutrient boost to outcompete the algae. Potassium encourages root and stem growth in aquatic plants, which soak up nutrients algae need. Just go easy—too much ash can spike the pH and harm fish. I use about a tablespoon per 100 gallons of water and monitor the results.
10. Remove Skunk Stink
If your pet has ever had a run-in with a skunk, you know how hard it is to get rid of the stench. Because fireplace ashes absorb odors, you can use them to get your pet smelling better, faster. Just rub ashes into your pet’s fur to absorb the smell.
My dog had a skunk encounter last summer, and let me tell you, it was rough. Rubbing dry ash into his fur before a bath cut the smell way down. The ash’s alkaline nature neutralizes the sulfur compounds in skunk spray. Be gentle, though—rub it in lightly to avoid irritating your pet’s skin, and follow up with a good shampoo. It’s not a complete fix, but it’s a solid first step and costs nothing.
11. Clean Up Soot
In the same way that a wood-ash paste can remove tarnish, it can be used to remove soot from fireplace doors. When you are cleaning your fireplace, simply mix ashes and a little water into a paste. Use the paste as a mild abrasive to get that glass shiny and clean again.
This is my go-to for cleaning the glass doors on my fireplace. A paste of ash and water cuts through soot like nobody’s business. I use a damp sponge, dip it in the paste, and scrub lightly—works every time. The ash’s abrasive texture lifts the soot without scratching the glass. For extra stubborn spots, I let the paste sit for 10 minutes before scrubbing. It’s a free, effective cleaner that’s already sitting in your fireplace.
12. Make Natural Bleach
When wood ash is mixed with water, the resulting substance is called lye water. Lye water is often used in soap, but it can also be used by itself as a bleaching agent. A cupful added to a load of wash should do the trick.
I was skeptical about this one, but I tried adding lye water to a load of white towels, and they came out noticeably brighter. The lye’s high alkalinity breaks down stains and boosts cleaning power. I mix about a cup of ash with a gallon of water, let it sit for a day, then strain it to get clear lye water. Be cautious—lye is strong stuff, so don’t use it on delicate fabrics, and wear gloves when handling it.
13. Control Humidity
Wood ash is a desiccant that you can use to dry out humid spaces, like damp basements and poorly ventilated bathrooms. A small tray of wood ash in the corner can help draw the humidity out of a room.
My bathroom used to get so humid that mold was a constant worry. A tray of ash in the corner worked wonders for keeping things dry. The ash absorbs moisture like a sponge, reducing the risk of mold growth. I swap out the tray every couple of weeks to keep it effective. For larger spaces, you might need a few trays, but it’s a low-cost way to tackle humidity without a dehumidifier.
14. Deter Ants
Have ants taken over in your lawn? Sprinkle a layer of wood ash over those ant hills to force them to relocate.
Ants were marching across my patio last summer, and a sprinkle of ash sent them packing. The ash’s texture and alkalinity mess with their trails and make the area less inviting. I used a thin layer around the base of my outdoor furniture, and it kept the ants away for weeks. Reapply after rain, and don’t sprinkle too close to plants that prefer acidic soil, as it could throw off their pH.
15. Put Out Fires
Like sand, fine wood ash can smother a small fire. Keep a bucket of cooled ash close to the fire pit or fireplace in case you need to extinguish any wayward embers.
This tip has been a lifesaver during backyard bonfires. I keep a bucket of cooled ash nearby, and it’s great for quickly dousing stray embers. The ash cuts off oxygen to the fire, just like sand or dirt. Make sure the ash is completely cool—warm ash can reignite. I learned that the hard way when a “cool” bucket turned out to be not so cool. A quick stir with a stick before using usually does the trick.
16. Fertilize Your Lawn
When applied appropriately, untreated wood ash has been shown to increase soil fertility and significantly improve crop growth. And what’s good for crops is good for turf. The potassium content of ash promotes root growth, while its alkalinity helps balance pH levels. Many lawn fertilizers contain high levels of nitrogen, which can eventually lower soil pH. Sprinkle cooled ash evenly over the lawn and water. However, don’t apply too much wood ash in the garden, or apply it too often. Excessive application can lead to an imbalance in the soil.
My lawn used to look patchy until I started using wood ash as a fertilizer. The potassium really helps grass develop strong roots, which is key for a lush lawn. I spread a thin layer—about a pound per 100 square feet—and water it in well. Last year, my lawn was the greenest it’s ever been. Just test your soil first; if it’s already alkaline, skip this or you’ll end up with yellowing grass. A soil test kit is your best friend here.
17. Create Pottery Glaze
Wood ash can also be used as a pottery glaze due to its high mineral content. Use rubber gloves and a mesh sieve to remove larger particles. Gradually add water to create a slurry and then use a brush or spray to apply the slurry onto your pottery pieces before firing them in a kiln.
I dabbled in pottery last year, and using wood ash for glaze gave my pieces a unique, earthy look. The minerals in the ash, like silica and calcium, melt in the kiln to create a glossy finish. I found sifting the ash through a fine mesh sieve is key to avoiding gritty textures. Mix about one part ash to two parts water for a smooth slurry. If you’re new to this, test on a small piece first—kiln temperatures can affect how the glaze turns out.
18. Make a Dust Bath
Dust bathing is an important cleaning ritual for chickens since it helps keep their feathers clean by killing critters like lice, mites, and fleas. Fill a low container (a shallow bin or sandbox will work) with soil and wood ash, and let your chickens dust off their tail feathers.
My neighbor keeps chickens, and I’ve seen how happy they get in their ash-soil dust bath. The ash’s drying effect kills parasites by dehydrating them, keeping the flock healthy. I helped her set up a bath with a 50-50 mix of soil and ash in an old tire, and the chickens went to town. Refresh the mix every couple of weeks to keep it effective, and make sure the ash is free of any chemical contaminants.
19. Repel Mice
Like snails and slugs, mice don’t like the abrasive texture of wood ash. Sprinkle a thin layer around the perimeter of your space—especially near entry points like doors and windows—to keep mice at bay.
I had a mouse problem in my garage last winter, and a line of ash along the door frame worked surprisingly well. The ash’s gritty texture irritates their paws, and they avoid crossing it. I sprinkled a thin layer—about a quarter-inch thick—and checked it weekly to make sure it wasn’t disturbed. It’s a simple, non-toxic way to keep mice out, but you’ll need to reapply if it gets wet or windy.
20. Store Seeds
If you’ve got seeds laying around but aren’t ready to plant them yet, wood ash is an effective method for storing seeds. Place a thin layer of ash at the bottom of an airtight container. Place the seeds on the ash and then apply another layer of wood ash on top. Seal the container tightly and store it in a cool, dry place.
I started using this method for my vegetable seeds, and it’s kept them viable for planting season. The ash absorbs moisture, preventing mold and rot, which is a common issue with seed storage. I use a small mason jar with a layer of ash about a half-inch thick on the bottom and top. Last year, my zucchini seeds stored this way had a near-100% germination rate. Just make sure the container is truly airtight to keep humidity out.