Fresh coffee grinds as soil - bad idea

[StillShaving]

We had a Peace Lily houseplant that had overgrown its container and needed subdividing. These are hardy houseplants and difficult to kill unless one neglects to water them. I've had the same one growing/dividing for about a decade.

I sub-divided the main plant into two main parts, with a third smaller part getting special treatment. The special treatment was to re-pot into a soil made up of 100% spent coffee grounds, mainly espresso grind.

I carefully subdivided and potted a couple of small bulbs/knots into my custom coffee grind mixture. The part I propagated was a little too small to be the final word on this subject, but I would have expected it to do well with proper soil. After potting and watering, the first thing I noticed is that the soil had the texture of concrete. A soupy, firm mixture that did not look good for plants. But in the interest of science, I let the peace lily remain in the pot. 24 hours later (+/- a few hours) the plant was dropping and looked to be dying. I took it out its misery and re-potted into proper soil, but the plant never recovered. Bottom line is that non-composted 100% coffee grinds do not make a good soil, but I am sure most of you knew that already.

I was hoping the experiment would work, to see if the exposure to caffeine had any effect on the plant, but I need better soil mixture/preparation for that. Ultimately I am curious to try this on some roses and other flowers that are prone to insect problems, to see if the plant will take up the caffeine and provide any degree of a natural bug repellant.

 

[SiBurning]

http://www.gardensalive.com/article.asp?ai=793

 

[Vlad]

I had similarly poor results with coffee grounds, suspected it was the acidity.

 

[nff]

yea you'd have to balance the ph of the mixture before even thinking of using it.

 

[TheVez2]

I've found Peace Lilys to be fairly non tolerant of anything added to the soil aside from water. I used to add Miracle Grow to all of my houseplants, except for my Lilys. The only time I tried, I ended up with a wilty looking plant by the end of the day. I thoroughly flushed the soil to get rid of the miracle grow and it slowly recovered.

 

[StillShaving]

http://www.gardensalive.com/article.asp?ai=793

Article makes important point about just how low the pH is in spent coffee grounds. My lawn soil is generally too acidic and that is without any coffee ground mulch (properly or improperly prepared).

I've found Peace Lilys to be fairly non tolerant of anything added to the soil aside from water. I used to add Miracle Grow to all of my houseplants, except for my Lilys. The only time I tried, I ended up with a wilty looking plant by the end of the day. I thoroughly flushed the soil to get rid of the miracle grow and it slowly recovered.

Interesting that your Lily acted this way immediately, maybe they are more sensitive to soil/nutrient conditions than I thought. I didn't really think fresh coffee grinds would work, but I had the easy opportunity to try this experiment. After seeing immediate failure, I thought it was due more to poor soil drainage, where the similarly sized small coffee particles prevented water from migrating to the roots, essentially drying it out. But seems the acidity must have had a bigger impact.

 

[nff]

get a ph tester kit and play around with garden lime till you have the proper ph level. then try something more hardy than lillys

 

[gearchow]

My wife used to take out the spent grinds and spread them around the plants, basically becoming part of the mulch. Best you can do with them I think.

I do need to try to spread them around our Hydrangeas, I wonder if there is enough acidity left (if ever) to deepen the blue color?

-jim

 

[ackvil]

However, coffee grounds work wonders around rhododendrons and blueberries.

 

[zethreal]

I spread my coffee grounds around on top of the soil by my plants and I try to not get any clumps around the stem. I actually spread the coffee grounds more for the worms than the plants, as earthworms love coffee grounds & large numbers of those will help your plants.

 

[cpeter47]

I had similarly poor results with coffee grounds, suspected it was the acidity.

I was going to say something like this. I'd assume the coffee grounds are way too acidic for plants.

 

[StillShaving]

I spread my coffee grounds around on top of the soil by my plants and I try to not get any clumps around the stem. I actually spread the coffee grounds more for the worms than the plants, as earthworms love coffee grounds & large numbers of those will help your plants.

Shane, interesting that you say this, I searched around and found a number of different references about this. A couple of the more interesting threads:
So why exactly do worms love coffee grounds so much?
My worms don't like coffee

 

[zethreal]

Well, through my experience, they do like it. I have a garden with mostly the same plants on both sides & they both get about the same amount of water & sunlight... the side closest to my front door gets the most coffee grounds ( as I just throw them out the front door onto the lawn/plants ) and I normally also find the most earthworms/nightcrawlers there. I haven't done anything scientific, but the ones where I am seem to like coffee

 

[takeshi]

Fresh coffee grinds as soil - bad idea

100% coffee grounds as soil is a bad idea. Good for compost though (again, assuming your compost pile isn't 100% coffee grounds).