A bucket of wood stove ashes

Why Use Wood Stove Ashes in the Garden?

One source of free fertilizer is wood ashes from your woodstove. If you have a wood-burning stove, you can put the ashes to use in your garden rather than disposing of them. Here are some ways to use wood ashes in the garden.

Fertilize Your Garden Soils

If your garden’s pH is too low, adding wood ashes will raise it because they contain calcium, potassium, and phosphorus. Ashes also contain about three times as much calcium as lime.

Be careful not to add too many ashes to your garden soil since an overdose will make it difficult for plants to take up vital nutrients like iron. Also, don’t add ashes to soils where you’ve recently applied sulfur because that will reduce the sulfur’s effectiveness.

Hand holding container with wood stove ashes and pours in soil.
Fertilizing soil with wood stove ashes

The ideal way to raise your garden’s pH is to have your soil tested so you’ll know how much wood ash to add. You can test your soil yourself or send a sample to your local cooperative extension office for testing.

Control Pests and Diseases Naturally

Wood ashes can be used as a natural fungicide to control black spot on roses and powdery mildew on squash plants, cucumbers, and pumpkins. To make a fungicide, steep two cups of ashes in a gallon of water overnight then strain out the large pieces in the morning.

Use the liquid fungicide on plants every seven to 10 days until the problem is gone or reduced. You can also use wood ashes as an organic insecticide against pests like slugs and snails by sprinkling them around the base of plants that these pests are attracted to.

Just be sure not throw any ash near open wounds since it can cause irritation.

Ashes can also be used as a preventative measure against some diseases like blights and webworms. Every spring, sprinkle wood ashes around the base of tomato plants and pumpkin vines to keep these diseases at bay.

Attract Wildlife to Your Garden

Woodpeckers love suet, which is rich in fat and calories that these birds need for energy during cold winter months.

You can make suet at home by mixing equal parts melted lard or shortening, birdseed, cornmeal, and wood ashes then pour the mixture into an empty milk carton or plastic container with small drainage holes punched into the bottom.

Once it hardens, cut a hole in the container large enough for birds to get through and hang it from a tree branch where birds will see it easily. Don’t forget to replace the suet feeder every few weeks so it doesn’t spoil.


There are many reasons to save those wood stove ashes for use in your garden rather than disposing of them in some other way. So next time you clean out your woodstove ashtray save them for use in your garden.