Coffee lovers, these lines were written for you! Instead of throwing your used coffee grounds away, use them in your garden, your plants will thank you for it! If you’re not a coffee drinker, you can still reap the benefits of using coffee grounds. Just ask the neighborhood coffee shop for a bucket or two of fresh-pressed coffee grounds!
A natural fertilizer
Coffee grounds contain high levels of potassium, magnesium, phosphorus and copper. It’s an excellent item to combine with other natural fertilizers such as fermented nettle tea or crushed horn and bone powder. Since these last few are chock full of nitrogen, when paired with your coffee grounds you’ll be giving your plants all they need to thrive. Spread it at the foot of plants or mix it into the soil.
A pest repellent
Coffee grounds pack a powerful smell. We love it, but pests like slugs, snails, aphids, ants, flies and nematodes hate it! Sprinkle it generously around your young seedlings to divert those mollusks away from them. Remember to do this more than once to extend the coffee’s pest-repellent properties, especially after it rains.
A cat deterrent
Yes, we love our cats and kittens, and with their purrs and cuddles they sure love us back. But for some strange reason they just can’t understand a few basic things, like not to nibble at our prize peace lily or poo all over the brand new perennial flower bed! To keep your cat from leaving teeth marks on leaves, wipe them with coffee grounds. Spread some grounds at the foot of the plant and spray the leaves with coffee (not hot! at room temperature only). The smell will send the cat further off, especially if you double down and add citrus peels, too.
Compost, a great destiny for coffee grounds
Just like weedy tea, coffee grounds trigger and activate compost activity. The biological activity it induces speeds up decay and breakdown of organic matter into nutrients. One word of caution: coffee grounds shouldn’t be the major part of what goes into your compost. If there’s too much of it, it’ll slow plant growth.
Acidify the ground
Coffee grounds naturally alter the soil’s pH levels. If you’re growing lots of heath plants, you’re in luck: it’s just what your soil mix needs! It works even better with fresh, unused grounds if ever you’ve got a batch that has lost its flavor. Hydrangeas will stay blue even if the underlying soil is neutral. In alkaline soil, you can’t really change the pH, even over time. It’s much simpler to use pots for growing in that case.
A worm magnet
Coffee grounds attract worms, and these mix the grounds deep down into the soil. This benefits the soil as a whole, on top of feeding worms a healthy dose of nutrients. Worms are essential because as they burrow around, their galleries help bring oxygen for micro-organisms to breath with. Coffee grounds can thus be included in a vermicompost with no restrictions!
Soil mix for sowing and seedlings
Once dry, coffee grounds can be used as a growing substrate for seedlings. Thanks to its nutrients and pest-repelling properties, it’s ideal for young seedlings. However, you shouldn’t use it pure. Mix it into seedling soil mix and a good portion of sand. Pure coffee grounds will stunt seedlings and also won’t drain well enough.
Clear black ice
Black coffee against black ice! Just like salt, coffee grounds are excellent to avoid slipping on black ice in walkways when it freezes over. It works chemically in the same manner as salt does (acidic water has a lower freezing point), but it’s 100% respectful of the environment. Salt, on the other hand, is a poison for plants and when it washes out, it kills entire ecosystems.
It will restore the wood’s original colors and masks scratches.
- Test on a small hidden portion first, changing the color of wood is always worth testing first!
A substrate to grow mushrooms on
Since it’s cheap (even free!), ground coffee waste is a great alternative to grow your own mushrooms on it. All you need to do is fill a bag up with coffee grounds and mix a strand of mycelium in. Three weeks later, after storing it in a dark, warm spot, just bring the pouch out into the light and water it to maintain constant moisture. Sprouting usually occurs ten days later: tiny mushrooms that will swell within hours!
- Read also: more garden uses for coffee grounds
Coffee in the press by Scott Schiller under © CC BY 2.0
Seedling by Cornelia Gerhardt under © CC BY-SA 2.0
Coffee pod in plant pot by Dennis Tang under © CC BY-SA 2.0
Snails on a post by Jernej Furman under © CC BY 2.0
Compost by melGreenFR under Pixabay license
Worm in hand by Timothy Musson under © CC BY-SA 2.0
Black ice by Maja Kuzmanovic under © CC BY-SA 2.0
Wood dye and renovator by ML Santander under Pixabay license
Mushroom growing on substrate by U.S. Department of Agriculture under Public Domain