Josh Cusack

I found this study showing a significant portion of the caffeine remains in coffee grounds after brewing.

https://pubs.acs.org/doi/abs/10.1021/jf3040594

I recently have read some articles that have made me think twice before putting coffee grounds into my compost or spreading in the garden as mulch. The articles that concern me make the case that the caffeine in coffee grounds is bad for plants because caffeine is the coffee plant's chemical used for allelopathy. The author of one article did a small test of his own showing bad results when adding coffee grounds, and another more scientific test showed equally poor results hinting at possible phytotoxic tendencies in coffee grounds.

the guardian
sciencedirect


So my question for all of you is, can anyone confirm these types of results?
And, if these results do rest on the presence of caffeine are there easy methods for ridding caffeine from used coffee grounds?
I have thought about soaking them in water and filtering it out (essentially brewing coffee on a bigger scale) a couple of times to get more caffeine out of the grounds, but then I worried about also leaching out nutrients.

Let me know what you guys think.
Thanks

I had a couple of questions regarding a wildflower garden that I converted from lawn, which was sprayed a few times a year with broadleaf weed herbicide. The first being how much should I be concerned considering that I was able to grow wildflowers in this spot last year, could it really be all that bad. My second question is, if I did inoculate the area with the white rot fungi, like you suggested, while the wildflowers were growing would it be detrimental to them? I know for a fact broadleaf herbicides were used but I am not exactly sure which ones.