Grounds for the Garden

Volta produces a few hundred pounds of high quality coffee grounds every week. For the last year, the good folks at Edible Landscapes have been picking all of it up for their composting operation-- until our production outpaced their demand. The grounds make great compost and also work as a mulch. While unbrewed, ground coffee is highly acidic, grounds from brewed coffee are pH neutral and very rich in nitrogen.

Volta's grounds are free for the taking. We have each day's espresso and brewed coffee grounds (along with organic tea and the occasional agua fresca watermelon rind) in individual plastic bags. Just ask your barista for a bag of grounds if you want to start working coffee compost into your garden or landscape. First come, first served: if you want an entire week's output, just ask.

Seattle gardener and author Ann Lovejoy offers her advice about using coffee as a compost:

Used coffee grounds have many uses, from mulching to compost building. This is one ubiquitous material it's hard to have too much of. If you decide to mulch your beds and borders with ground coffee, here's a hot fashion tip: Remove the filters first. Those raggedy white papers look too tacky for words when left fluttering around your flowers. White or brown, you can shred the filter papers and mix them into the compost, where they'll break down nicely in short order.

Ground coffee is high in nitrogen, making it a very good mulch for fast-growing vegetables. Many organic growers swear by coffee grounds as mulches for tomato plants, both for the nitrogen boost this heavy feeder appreciates and for coffee's ability to help suppress late blight.

Coffee-ground mulch also can help reduce the ravages of slugs and snails. At a recent class, one participant announced that she always mulched her hostas with coffee grounds each day and had never before understood why they were never bothered by slugs.