my mother does 

 What does she it use on? 

Any idea of the effectiveness? 

 1) nope 
2) she is always right  

 I put all of mine in compost worm bin mixed in with biochar. After that I’ll dig a little spot by the plant and place the material. 

 Yeah it goes in the compost, I don't know why. I just know when I worked in a cafe gardeners used to collect the stuff especially. I think it's the right moisture amount, not even sure what other properties it might have which are useful. 

I like to think I'm caffeinating the worms. ☕ 

 I use them all around the garden and feed them to my worms. I make some pretty good soil. i'm a worm wrangler and a soil tender. 
when we #compost we #capturecarbon and #buildsoil 
don't worry about fertilizing a plant. build life in the soil and let nature do its thing. plants take only what they need, if it's there. 

 I scatter them all around, I've found the snails hate them  

 Them worms love the coffee grounds! 

 I've fed my coffee grounds to my worms and use the worm compost to feed my garden.