Uses for old coffee grounds

We don’t want anything to go to waste and one of our by-products is coffee grinds so we’ve been investigating what we can do with them.

The obvious option is fertiliser. Coffee grinds are 2% nitrogen, 0.06% phosphorus, 0.6% potassium and contain loads of micronutrients, so fertiliser is an awesome option for house plans and balconies. Expanding on this concept, if we combine a small amount of soil and coffee grinds in a biodegradable cup, add some seeds like beans or okra, you have a seed bomb - just plant the whole thing and water. Coming soon to our online store!

Coffee grinds are also an insect repellent. Flying insects like Mosquitoes and wasps don’t like the smell of burning grinds, crawling insects like ants and slugs are not so fond of the aroma and other insects like fruit flies, beetles and fleas are also not so keen. So I can see a coffee grind oil burner in our future somewhere. Incidentally, worms don’t like coffee grinds either, so fertiliser is best for indoor plants rather than the garden.

If coffee grinds repel fleas could they be combined with a pet shampoo? Yes indeed they can. Grinds contain caffeine and diterpenes which are both toxic to insects. Caffeine is a cyclic alkaloid which is a potent neurotoxin to insects. For this reason though both humans and pets should avoid ingesting coffee grinds in any quantity.

My final thought is mushrooms. As a spin off from the fertiliser idea coffee grinds can add all the nutrients needed for a mushroom bag, which you can grow in dark, moist conditions. We might need to experiment with that one to get it right but it’s a rapid growing, high yield crop in the right conditions.