Coffee grounds deter slugs

Wed. May. 8, 2019

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Coffee grounds deter slugs

There have been a number of claims about using coffee grounds in the garden.  Do they really work? Well, as with most home remedies, they are still being studied!  Claims of disease control to enhanced growth and more, generally, means that success varies. There are some who say don’t use them at all.  I generally offer university based information but sometimes you’ll find nuggets of knowledge that science just doesn’t bother with!

Coffee Grounds and composting from Oregon State. 

  • However, there are some reasons to give it a try.  For one thing, adding coffee grounds to your compost pile isn’t a bad idea. The grounds add some nitrogen, they’re considered a green material so you don’t want to add too much.  In fact, keep it at less than 20%. And just to be on the safe side, don’t include the white filters, they are bleached.
  • You can add a layer of coffee grounds around your plants, as they break down, again, they’re slowly adding a little nitrogen.
  • And here’s a cool thing, a thin layer of coffee grounds not only improves the soil, the abrasive, sharp edges and coffee’s natural acidity combine to make a good slug barrier. The Spruce says that, in fact, research suggests that caffeine is toxic to slugs, making it a double whammy. Keep the layer at no more than an inch thick, otherwise those grounds will compact and form a crust that that won’t allow air or water through. NOTE:  this is disputed by others.  Well, just about anything is!  😉 
  • They also suggest adding coffee grounds to your worm bin. 

I generally add my coffee grounds to my compost. I also you bamboo filters which are not treated so can be tossed in right with my other kitchen scraps. As noted, don’t collect from your local coffee shop and dump all those grounds on your compost.  Your own is likely enough.

finished compost ready for garden bed