Used Coffee Grounds

[BobT]

I find that I prefer coffee made without using paper filters. It seems the paper filters out more than just grounds but also flavor. So I have been using a screen type filter. I also find that I like using a French press with my fresh ground coffee which also employs a micro screen.

This creates a small challenge - what to do with the spent grounds, especially those left from the press. Too moist for the trash.

For a while I have been just rinsing the screens and sending the grounds down our sink drain. We live on a farm and have our own septic system. I have been reading that it is not recommended to dispose of coffee grounds down the drain because doing so can result in the acid from the coffee lowering the pH of the septic system which could kill the needed bacteria.

Today, I searched for the question, "What to do with used coffee grounds" and one common solution is to sprinkle them as fertilizer for the garden or potted plants. But, if adding coffee grounds to the septic system could potentially lower pH, wouldn't it do the same for garden soil and potentially rendering it too acidic over time? 

I also found quite a few articles stating that the acid in coffee is water soluble and ends up in the coffee and the used grounds are pretty much neutral between 6.0-6.5. Other articles I read say they can continue brewing in the septic system which can extract more acid.

I'm spinning in circles.

Anybody have any knowledge of this chemistry?

[smurfy]

Nope not a chemistry major but I've been throwing spent/ used coffee grounds in my garden and lawn for many years. Even in my wife's flowers. A guy with a 4 year biology degree told me they are an excellent source of nitrogen. I also googled it and pretty much came up with the same conclusion.

[BobT]

Thanks. It seems my question is about as bad as the Covid-19 questions. I find almost as many references claiming it is good for the garden as I find references claiming it is not good for the garden. So far I've found only one study that was conducted by Oregon State University Extension and they said used coffee grounds are pH neutral. 

[ozzie]

I just throw them in the garbage.   Interesting to know if they do help gardens and grass grow as it would get me to spread them on the lawn all summer.

 

[smurfy]

39 minutes ago, ozzie said:

I just throw them in the garbage.   Interesting to know if they do help gardens and grass grow as it would get me to spread them on the lawn all summer.

 

like the guy with the biology degree told me, used coffee grounds are a good score of nitrogen........there is nitrogen in all lawn fertilizers!!!!! we dumped coffee grounds in worms as kids when we sold worms.....kinda like worms on steroids!!!!!!!

[leech~~]

Well it may work but I sure as ha!! ant going to pry all those little Keurig cups apart for a few oz's!

[smurfy]

7 minutes ago, leech~~ said:

Well it may work but I sure as ha!! ant going to pry all those little Keurig cups apart for a few oz's!

Yea well some of us can't afford Keurig. and I drink most of a 12 cup pot of coffee every day.