If you’re a gardener, you have yet another reason to love your fireplace. Wood fires naturally create ash, and adding ash to your garden in moderation can be a cost-effective way to boost your plants’ growth. So, which plants like wood ash, and how can you use it?

Using Wood Ash as a Soil Amendment and Fertilizer

Wood ash isn’t as concentrated as commercial fertilizers, but it’s a good source of potassium (the second ingredient, after nitrogen, on fertilizer bags). Ash also contains useful quantities of calcium, phosphorus, and magnesium, as well as trace minerals such as boron, copper, molybdenum, and zinc.

Ash’s high calcium content means it’s useful as a soil amendment to help raise the soil’s pH. Before applying wood ash to your soil, conduct a basic soil test to determine whether it needs these nutrients. A good rule of thumb is 5 pounds of wood ash (roughly what you’ll get from a cord of wood) per 100 square feet of soil, applied once a year. For example, if you have a raised garden bed that measures 4 feet by 8 feet (totaling 32 square feet) you would need just over 1.5 pounds of wood ash to treat the soil.

But is wood ash good for plants? It depends. Calcium deficiency in your soil can cause blossom-end rot in tomatoes, and the ash may be a helpful remedy. It’s also useful if the soil is too acidic for your plants’ liking.

If you have acid-loving plants such as blueberries, rhododendrons, and holly, however, avoid using wood ash as fertilizer. Keep it away from potato patches, too, as wood ash can lead to scab, a soil-borne disease.

Adding Wood Ash to Compost

Another way to use wood ash in the garden, without worrying about which plants will or won’t benefit from it, is to put it in your compost instead of applying it directly to the soil. It can be chucked into the pile along with grass clippings, sawdust, leaves, coffee grounds, vegetable scraps, crushed eggshells, and cardboard.

A working compost pile is mildly acidic, so moderate amounts of wood ash can help keep it balanced. Anything up to 5% of your pile by volume is fine. Beyond that, your compost may become too alkaline, which will slow its decomposition.

There are a few other caveats as well: Don’t use ash from painted, stained, or pressure-treated wood, or charcoal ash from your grill, which can contain toxic chemicals. Additionally, never add hot ashes to your compost pile as it can catch fire. Within those limitations, wood ash can genuinely help your garden thrive.

How To Use Coffee Grounds on Your Plants

The simplest way to put those grounds to use is by watering your houseplants with them. Here’s how it works: 

Step 1: Save the grounds from your coffee maker. If you use a pod-style coffee maker (Nespresso, Keurig, Tassimo, and similar systems), keep a container handy to collect the used pods. Drip coffee users can just use the contents of this morning’s filter.

Step 2: Empty the grounds into a pitcher or large measuring cup. If you’ve been saving pods, carefully cut them open and shake or scoop the grounds into your pitcher. Add room-temperature water to the grounds, and give them a stir to make a slurry of water and coffee. The consistency should be relatively thin as the goal is to dilute the coffee grounds as much as possible.

Step 3: Water your houseplants (or your garden) with the slurry, no more than once a week. It’s ready to use right away, but if you let the slurry rest for 20 to 30 minutes, the coffee’s nutrients have more time to dissolve into the water.

What Used Coffee Grounds Do for Plants

The slurry is essentially weak coffee, infused with nutrients and beneficial grounds. Brewed coffee is slightly acidic, and causes acid-loving plants such as African violets, cyclamens, begonias, Christmas cactus, and jade plants to perk right up. Avoid giving coffee grounds to plants that prefer alkaline soil as too much acidity can harm them. These include lavender, lilacs, roses, tomato plants, thyme, and rosemary.

If you have an outdoor garden, you can use your slurry there as well. Researchers at Oregon State University found that a coffee drench applied to garden beds deterred slugs, and noted that caffeine could actually kill the garden pests in specific concentrations. An article published by Washington State University further suggests that coffee can protect plants from common soil-borne infections, including fungal rots and wilts, and certain bacterial pathogens.

Now cinnamon’s surprising versatility has it going viral on social media for another reason: its use as a DIY natural insect repellent. Here’s how you can create a cinnamon-based bug spray to keep the creepie-crawlies at bay around your home.

Four-Ingredient Cinnamon Bug Spray

Making your own natural insect repellent is as easy as making yourself a cup of instant coffee. The recipe calls for just four ingredients: ground cinnamon, water, rubbing alcohol, and dish soap. Keep in mind that natural bug sprays tend to lose their potency fairly quickly, as their volatile oils evaporate, so only make as much as you plan to use within the next week or so.

Step 1: Using a ratio of 1 teaspoon of ground cinnamon for every pint of water — so, 2 teaspoons for a 4-cup batch, or 8 teaspoons for a half gallon — stir the ground cinnamon into warm water and let it steep for at least an hour. Then pour it through a fine-mesh strainer right into your spray bottle. If you’re worried about spilling, line a funnel with a paper towel or cheesecloth and use that to strain your concoction.

Step 2: Once the cinnamon and water mixture is in the bottle, add a quarter teaspoon each of rubbing alcohol and dish soap for every pint of water you’ve used (so a half teaspoon per quart, or 1 teaspoon for a half gallon).

Step 3: Mist the bug spray liberally around doorways and windows to repel ants, or in your closets to discourage spiders and earwigs. You can even spritz yourself to keep pesky mosquitoes away.

Is There Some Science Behind This? 

Unlike a lot of viral DIYs, this one is well supported by research. Cornell University’s Integrated Pest Management program hosts a 16-page paper outlining cinnamon’s capabilities as an insect repellent. The short version is that it’s safe for humans and our pets, and it genuinely does repel a lot of pests. (It’s even used in commercial agricultural products.) So mix up a batch, and start spraying.