Coffee: Keeps bugs at bay and it’s great for the garden

This guy came up with a great mix of sawdust and coffee to keep mosquitos at bay while he was doing some yard work. This worked really well for him. But if you don’t have sawdust – don’t panic. Straight coffee works perfectly.

To be clear, burning ground coffee appears to work better than burning dried grounds, because the natural oils are more concentrated in their pre-used form. Put a spoonful on a piece of tin foil, light it and allow it to smolder, like you would with incense. Used grounds, can be burnt, but they can also be used in the garden to keep down pests such as as ants, slugs and snails; to add fiber to sandy soil, and to provide nutrients. (See below)


Click here IMG_1608 – to see  a video I took of my own coffee smoldering. I can see why sawdust is a good idea. I added some cigar tobacco as that’s what I had, and that kept it going a bit better.

From the EPA Climate for Action blog:

New Uses for Used Coffee Grounds

Many of you may be looking for effective green tips.  One tip I can offer you is to recycle used coffee grounds. Coffee mixed with soil can be used as a natural fertilizer. Used coffee grounds provide gardens with an abundant source of nutrition. Recycling coffee grounds is not only beneficial for gardeners but it helps in reducing the amount of waste going into landfills. When coffee grounds are dumped into landfills they create methane, which is a greenhouse gas. Methane is known to be more harmful than carbon dioxide, another greenhouse gas that causes global warming. If we are able to keep coffee grounds out of landfills we’ll be one step closer to eliminating greenhouse gas emissions.

Coffee grounds contain a high amount of nitrogen. When scattered across soil before rain or watering they will slowly release nitrogen into the soil. When compost is mixed with coffee grounds it causes the soil temperature to rise and stay hot for long periods of time. The high temperature kills weeds and will allow your garden to flourish beautifully. Coffee grounds are acidic, which benefits “acid loving” plants.  For instance roses, camellias, blueberries, and azaleas all flourish when sprinkled with coffee grounds.

Recycling coffee grounds also helps to feed worms, and keeps troublesome insects away. Earthworms love to feed on used coffee grounds; it helps them grow and reproduce. Having lots of worms is an excellent way to keep a healthy garden. It is important to have worm activity in your soil; this mixes the soil and helps in mineralizing your vegetation. As you all know the odor of coffee is very strong, the odor can sometimes be too strong for humans. In the case of insects like ants, slugs, and snails the odor works as a repellant.

There are many places you can find used coffee grounds. Some good suggestions include local coffee shops, gas stations, schools, or your workplace. You could ask coffee vendors to save coffee grounds for you, and coordinate a time to stop by and pick up your “green fertilizer.”

Other uses for coffee grounds:

  1. Can be used to dye paper or clothes
  2. Can retouch furniture
  3. Can be used as flea repellant, rub on pets (dog, etc.)
  4. Can repel odors around the home
  5. Can be used when cleaning grease

Learn more about recycling used coffee grounds, and remember recycling is one way we can keep our environment natural and beautiful!

About the Author:  Loreal Crumbley, a senior at George Mason University, is an intern with EPA’s Environmental Education Division through EPA’s Student Temporary Employment Program (STEP).