Recycling used Coffee Grounds
• Coffee grounds from homes and cafés are an excellent addition to a compost pile. The grounds are relatively rich in nitrogen [about 2% in volume] providing bacteria the energy they need to turn organic matter into compost.
• Contrary to popular belief, coffee grounds are not acidic, after brewing, the grounds are close to pH neutral. The acid in the beans is mostly water soluble, so it’s been drawn into the coffee during extraction/brewing. Grounds contain potassium, sulphur, magnesium and calcium as well as nitrogen.
• If collecting coffee grounds in the café, remember to make sure that nothing else is mixed in with the grounds – no empty sugar sachets, cups, napkins etc. Grounds can be collected over 3 – 4 days and kept in a bin or garbage bag.
Using Coffee Grounds in the Garden
• When adding coffee grounds into the soil, add a little nitrogen fertilizer as well and keep the soil damp. The coffee grounds encourage the growth of microbes in the soil which are nitrogen users. While microbes are breaking down the grounds, the extra nitrogen will provide a source of nutrients for the plants.• If spreading the grounds on the soil surface, break up any clumps then cover them with a sprinkling of leaves or bark mulch.
• Add grounds to your compost or mulch pile, ideally layering one part leaves to one part fresh grass clippings to one part coffee grounds, by volume. Turn once a week and use after three to six months.
• Keep in mind that un-composted coffee grounds are NOT a nitrogen fertilizer. Coffee grounds have a carbon-to-nitrogen ratio of about 20 to 1, in the same range as animal manure. On their own, they need between 3 – 4 months to break down.
• Small amounts of used coffee grounds can be put in worm farms but make sure the grounds are damp and ideally mix in some other worm friendly waste.
• This all helps keep landfill down and plants healthy!