Garden Q&A: Coffee grounds perk up compost
Q: Are used coffee grounds good for fertilizer? Over winter, I have been adding coffee grounds to my compost bin to use for spring planting. Good idea or not?
A: Used coffee grounds make a great addition to the compost pile. They are approximately 2 percent nitrogen by volume and serve as an excellent nitrogen source in compost (much like horse or cow manure does). It was once thought that coffee grounds were acidic and that adding too much of them to a compost pile, or directly to the garden's soil, would cause an undesirable pH change. However, several studies have shown that the acidity is “washed out” during the brewing process and the used grounds have a fairly neutral pH.
Good quality, homemade compost is made by mixing carbon-rich ingredients (such as dried leaves, straw and shredded newspaper) with nitrogen-rich ingredients (such as untreated grass clippings, manures, coffee grounds and green plant trimmings). The fastest rate of decomposition occurs when there are two to three times the amount of carbon-rich ingredients by volume.
This means that for every gallon bucket of coffee grounds that go into the pile, you'll need two or three gallon buckets of dried leaves or other carbon-rich ingredients. Maintaining this ingredient balance means a more balanced finished product, with the right carbon-to-nitrogen ratio, and a pile that does not produce an odor. Turning the pile regularly also is helpful.
Compost is an excellent soil amendment that adds essential organic matter and improves soil structure. You can add unbleached coffee filters to the compost pile, but you should avoid adding any white, bleached filters.
If you don't (or can't) have a compost pile where you live, it is still possible to utilize those coffee grounds in the garden. You can spread small amounts of the grounds around the soil surface or bury them in small trenches. Do be aware, however, that while they are decomposing, even small amounts of coffee grounds will “rob” a bit of nitrogen from the soil. Though it is eventually returned to the soil, you should add a bit of nitrogen-rich fertilizer to the area whenever you add uncomposted coffee grounds. A dusting of alfalfa meal is often enough to prevent this temporary depletion of nitrogen.
Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio. She is the author of several gardening books, including “Grow Organic” and “Good Bug, Bad Bug.” Her website is www.jessicawalliser.com.
Send your gardening or landscaping questions to firstname.lastname@example.org or The Good Earth, 503 Martindale St., 3rd Floor, D.L. Clark Building, Pittsburgh, PA 15212.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- Redbank Valley’s Truitt, Kittanning’s Robb win PIAA 1st-round bouts
- Loose barges on the Mon highlight woes of winter’s end
- Pittsburgh has enough salt despite delivery refusal on Thursday, official says
- Angry fans cited in shortage of refs in Western Pennsylvania
- Mt. Lebanon deer-culling corrals sprayed with urine, repellent
- Police looking for man they say assaulted a 13-year-old girl
- Penguins notebook: Road trip increases in difficulty
- Agent: Polamalu undecided whether to play in 2015
- Parkway East closure lifted after truck with loose load of coils forces detour
- Drug charges filed against Monaca mother, daughter in teen’s death
- Federal judge dismisses complaint against foreclosure propery management company