How to Handle Fire Pit Ashes: Expert Outdoor Tips

Key Points

Properly handling fire pit ashes is essential to prevent accidental fires and ensure safe disposal or reuse for your home and garden. Understanding the correct methods for cooling, disposing of, and reusing these ashes can make a significant difference in maintaining safety and sustainability.

How to Safely Cool Leftover Fire Pit Ashes

When the nighttime fun is over and it’s time to extinguish the fire pit, it’s not so much the ashes that are the problem as the coals and embers hidden in them. “Heat is held under the surface that looks cold,” warns Nicholai Allen, an active wildland firefighter, and the founder of SAFE SOSS and CEO of MAUS USA, two fire protection technology companies. “Every year, fires are started by ashes that were dumped into plastic containers, cardboard boxes, trash cans, mulch beds or against structures before they were fully extinguished.”

The safest method is to thoroughly soak the ashes with water, stir, add more water, and stir again. “Don’t just wet the surface,” Allen says. “Ashes can retain heat surprisingly well, and hidden embers can remain alive long after the fire appears to be out.” Don’t assume the fire is out because the flames are gone. “Stir the ashes, expose any hidden heat, add water, and continue mixing until everything is cold to the touch,” he says.

While the fastest way to cool them is by dousing with water, this can make quite a mess on your patio. “It is also very hard on the fire pit itself, as it will heat-shock the unit,” shares Eric Tamminga, founder and owner of Iron Embers, a premium fire pit manufacturer. “It can also lead to premature rusting for steel units or cracking of concrete and stones for natural fire pits.”

Another method is to cut off oxygen to the fire by using a snuffing lid, then let the fire burn out naturally. Leave covered, wait a sufficient time (at least 24 hours to be safe), and then dispose of the ashes without making a mess.

Tips

• To minimize effort, consider only burning hardwoods like maple and oak. “These burn more efficiently than softwoods like pine and spruce,” says Tamminga, “and produce less ash. They also burn longer, which is a nice benefit as you sit and enjoy your fire.”

How to Correctly Dispose of Fire Pit Ashes

Once the ashes are completely cold, place them in a metal container with a tight-fitting metal lid. “Store it on a non-combustible surface away from structures, decks, fences, mulch, and vegetation,” Allen says. “Even ashes that appear dead can contain hidden embers capable of starting a fire. Follow local disposal guidelines as requirements can vary by community.”

Protective clothing and PPE (personal protective equipment) are also key, since ash can be irritating or caustic when in contact with the skin or eyes, or inhaled. Always wear a properly fitted and rated dust mask and gloves when handling.

Potential Reuses of Fire Pit Ashes

Wood ash is a great fertilizer, as you’ve burned all the carbon and hydrogen out of it. This leaves behind only potassium, magnesium, phosphorus, and calcium—which are all beneficial to your garden and lawn health.

“Potassium and magnesium are necessary for photosynthesis, phosphorus for flower development, and calcium for healthy root growth,” says Chrissie Handley, lawn care specialist and gardening expert working for Online Turf. “However, the levels of potassium will vary depending on the age of the wood that was burned.”

Wood ash is also quite alkaline, so can be used as a neutralizer if your soil is too acidic. “It can balance it back out and is great for plants that love a more alkaline soil, like roses or butterfly bushes,” Handley adds. “It’s great for use on tomato plants, as they need high amounts of calcium and potassium to thrive. Avoid using it on plants that prefer a more acidic soil, like azaleas or hydrangeas.”

Tips

• For garden use, apply wood ash in small amounts. Adding too much can damage the plants by making the soil too alkaline. Handley recommends adding a small amount to your compost pile sporadically, then adding this to your soil or as a mulch at the base of your plants. “This will ensure you’re diluting it into a more rounded fertilizer, though you can apply wood ash directly to your soil if you want,” Handley says. “It just leaves more room for accidentally adding too much.”

• Other reuses include pest control, landscaping, and winter chores. “You can sprinkle ash around your home as insects don’t like the smell,” says Philip Farina, founder and chief security and safety advisor for Risky Business. “If you have any low spots in your yard, you can use ash to help fill it in. Finally, it can help with de-icing in the winter months.”

Proceed With Caution

Don’t forget: If you are burning anything besides clean, natural firewood then your ashes could be contaminated with the toxins and chemicals from what you were burning. Look out for things like paint, ink, plastics, and packaging specifically. “Never burn pressure-treated wood on your fire pit,” warns Tamminga. “The ashes will be contaminated, but worse—the fumes coming off during the fire are quite toxic.”