When you make a cup of tea with a teabag, the caffeine comes out into the water - the spent teabag contains none, or a vanishingly small amount. My health food book advises dunking a teabag in boiing water, lifting it out within 10 seconds, throwing that away to get rid of the caffeine, then pouring fresh boiling water over the same teabag for your cup of tea. I don't do it, I find it reduces flavour too, so I just buy decaffeinated Earl Grey instead, but you get the point...

This link https://www.rhs.org.uk/advice/profile?PID=726 says you can add teabags to a worm composting system...

Hmmm...that said--and excellent info, too, Bamboo!--I'm now wondering about spent coffee grounds. Some research for me to do.

Wow! I wasn't expecting that Bamboo. So our worms are caffeine free anyway. I don't put coffee grounds in the bin Tugbrethil, but only because it's too messy for me. Intetresting info.

I was interested in that too Tug - done some checking and it looks as if there's still caffeine in coffee grounds, but worms love 'em anyway, so presumably, provided the CN ratio of a heap is kept at the right level (because as you know, too many coffee grounds can cause problems) the caffeine content is largely irrelevent in regard to worms. They apparently like slightly gritty foods for their gizzards see here http://homeguides.sfgate.com/worms-eat-coffee-grounds-103941.html

I only buy de-caffeinated tea bags. Have done for years.
Need some soft weed material to fill up my compost bin !

That's useful info aswell Bamboo. If worms like gritty grounds, I'll start trying to get used coffee to the compost bin without making a mess.

Experiments have been done with the amount of coffee grounds in compost and it's effect on the worms biomass. No difference has been noted to date.

Yes, from what I've been reading, the only hazard to worms is the possibility of making the heap too acidic.

Thanks everyone. Always learning.

I just place the coffee filter upside down in the kitchen sink to drain off the last of any liquid, (keep the plunger down). Remains just scrape into the kitchen compost bin.