Just curious what you gardeners think about coffee grounds?
Also what about coffee grounds in potted plants, curious about what others think.......



https://curiosity.com/topics/w...

Hmmmm - I always use coffee grounds on my roses, and they seem to like it. I do know that coffee grounds tend to lean towards acidic, so maybe not so good for plants that don't like slightly acidic soil? I also use them on my Amaryllis. I also use egg shells and banana peels too.

I think, like everything else, coffee grounds should be used sparingly on potted plants. In the garden, they can work wonders.

The eggshells will never decompose - you have to grind them into powder first. Banana peels? Fruit fly time. Like eggshells, they need to be blended or dried and ground up. Coffee grounds, by the time the coffee has been leached out (and then you drank it) make good compost but that's about it.

You should both start a compost bin, your garden will be more attractive and less buggy without food waste.

My compost bin if full of all three, and I have never had a problem.

@PamelaLynn77 -- This article says a bit of the same, but also very different - and I tend to agree with this article more. I have a lot of earthworms in my compost bin and they like coffee grounds -to the point that they open up baby nurseries in my bin. Also, by Amaryllis, roses and pepper plants seem to thrive on them.

https://www.gardeningknowhow.c...

It is my understanding that coffee grounds are acidic by nature. Coffee is an acidic drink. I would imagine that rhododendrons, azaleas and evergreens would like a soil with coffee grounds.
I am not sure about veggies but I think I read somewhere that they prefer a ph neutral soil.

Bill, the drink may be acidic but the grounds are not necessarily.

We have six compost bins and have added coffee grounds, eggshells, and kitchen waste for the 26 years we've had them: no odors at all.


As for the acidity in coffee grounds...

Every year I get a big bag of coffee grounds from Starbucks, use them in my compost, never an issue.

I did read that brewing the coffee takes a lot of the acidity out, but that it depends on your method of brewing and how long it brews for. I happen to use the coffee grounds on acid loving plants, but also when I test the soil it remains pretty neutral so I don't think it adds that much acidity. @pirl - it that meter in straight coffee grounds or treated soil? I can't tell.
As far as killing earth worms as stated in that first article - I have an old big pot that a tree came in that I use for my compost bin - earthworms climb up into it and breed - lots of baby wrigglers - they seem to do just fine with my coffee grounds. I add other stuff too though - banana peels, egg shells etc. But they seem to thrive. I even bring the grounds home from work to use - been using them for years.

"A commonly held assumption states that coffee grounds are acidic, but this does not hold true experimentally. While two studies on coffee ground composting reported mildly acidic pHs of 4.6 and 5.26, others have measured neutral (7.7) to somewhat alkaline (8.4) pH levels. One researcher found that the pH of soil treated with coffee compost increased after 14 to 21 days of incubation, gradually decreasing thereafter. Obviously the pH of decomposing coffee grounds is not stable and one shouldn't assume that it will always, or ever be acidic."

From Washington State University:
https://s3.wp.wsu.edu/uploads/...

When I tested my own coffee grounds they were 6.8. Some plants are actually inhibited by coffee grounds.

cwhitt, I can't figure out who you are disagreeing with.

Both testers were inserted in coffee grounds, no soil.

I just read on the Internet where brewing coffee is acidic but the brewing process renders the leftover grounds essentially neutral!!
Interesting!

So I stand corrected and informed.

@DaisyI - the article that @PamelaLynn77 was questioning up in her original post that said to never use coffee grounds in the garden. The author seems very authoritative in her writing, but what she is claiming does not really match up with my own experience.

Thanks Arlene! Very interesting meter results. Good article Sue.

cwhitt said:@DaisyI - the article that @PamelaLynn77 was questioning up in her original post that said to never use coffee grounds in the garden. The author seems very authoritative in her writing, but what she is claiming does not really match up with my own experience.

That article was about caffeine, not acidity. And, the sources they sited said mixing non-greens in, like paper and cardboard, cancelled out the effect of the caffeine.

The article also says that coffee grounds kill helpful bacteria and earthworms and does talk about coffee being "Highly acidic". The title of the article is "Whatever You Do, Don't Put Coffee Grounds in Your Garden". That is the actual question we are discussing - whether it is fine to use them in the garden, or not.