Comments on: The Coffee Grounds Conundrum

By: Bentley

Bentley — Thu, 30 Jul 2009 15:04:48 +0000

DON – I am definitely finding the same thing (importance of keeping wet wastes on top)
—–
MS – I definitely haven’t seen any evidence of this. In fact, the wet, well-aged zones of grounds seems to almost serve as a little nursery for the worms. I always find loads of babies.

By: ms

ms — Wed, 29 Jul 2009 07:17:32 +0000

I was told by the lady I work for that coffee ground is bad for the red worms, it will stop reproduction, any proof to this?

By: Don H

Don H — Sat, 18 Jul 2009 16:26:29 +0000

Your site has been a great help to me in my first six months of growing red worms. I have been getting bags of coffee grounds from Starbucks, (locations in Eastern Canada and New England offer them to gardeners) and experienced drying and a crust on the top. I have solved this by making sure wet waste is always put on top of them and the layer is sprinkled no more than 1 inch thick. I harvested my bin today for the first time and was amazed with the worm clusters mostly in the wet coffree grounds. Lots of cacoons as well which I will separate and add to the new bin. Next time I will use the bin harvesting method. Thanks for keeping up your site! Don H

By: Bentley

Bentley — Fri, 17 Jul 2009 16:09:20 +0000

ZEB – I definitely agree that coffee grounds are rich in cellulose, but I definitely wouldn’t say they are similar to sawdust / wood chips – since the C:N ratio of the latter material is generally MUCH higher. Grounds are actually considered a ‘green’ (N-rich) waste for the most part.
I think you are bang-on with the idea that it’s fungi doing most of the decomposition though.
What amazes me about this material is that it seems to be able to heat up a LOT even when concentrated in very small amounts. I think this could be very useful for our big winter bed once the weather gets cold again!

The little pockets I added to my trenches the other day (mentioned in a previous comment) were very warm when I went back to check on them (much warmer than the surrounding manure) – and they were already starting to dry out. Also – surprise surprise – there were no worms in them yet.

Anyway – definitely an interesting topic, and something I’m going to be looking into a lot more in coming weeks.

By: Zeb

Zeb — Tue, 14 Jul 2009 20:11:50 +0000

I would say yes! If the molds have moved in that means that the cellulose is being attacked, and it will soon be worm food. (-: Remember mold is a fungi too.
(There’s a pun there somewhere, but I’ll leave that to the more witty and fun guys out there in the crowd.)

By: Louis

Louis — Tue, 14 Jul 2009 13:17:20 +0000

Is it then a good thing if the coffee grounds become mouldy? I stand by my previous statement that it goes mouldy when I close it up in an airtight container. I have even noticed that it goes mouldy when under newspaper & plastic covering in my outside bins.

By: Zeb

Zeb — Mon, 13 Jul 2009 16:41:46 +0000

I never knew worm-talk could be so fun. (:

Well I think everyone will do well to consider coffee-grinds to be basically the same as finely ground wood chips sterilized by hot water. Coffee beans have a tough cellulose content which on it’s own isn’t very nutritious to anyone but (drum-roll) the fungus among us. Basic biology 101 taught me that without the fungi of the world we would be elbow deep in cellulose today – since only they posses all the right tricks to take fairly inert stuff like wood fiber and gracefully turn it back into the sugar from whence it came.

So like leaves and wood chips – once you get some decay started, yum! Worm food! But it’s not fast as with vegetables and their low cellulose / high sugar and water content.

Let me know if this idea pans out. If coffee behaves similarly to sawdust in your worm bins then I think we’ll have a good working theory! I know my outdoor compost bins LOVE wood chips and coffee and get piping hot each time I mound up another heap of mixed grass clippings and chipped tree branches (plus a good watering). I’ve then observed weeks later my normal earth worms moving up into that mass as they go to town. I live in the German countryside now as an ex-pat, but I was quite surprised to discover my first monster Euro-worms when I originally got here! They are like.. Snake sized!

But regardless of size, they only move in after the molds and fungi have done the ground work. Must be the same with coffee. I’m not quite ready yet, but I can’t wait for the day when I start my first red-worm bin. Thanks to everyone for the wealth of info!

By: Berwick Worm Farm and Waste Systems

Berwick Worm Farm and Waste Systems — Mon, 13 Jul 2009 15:53:56 +0000

There must be something in coffee grounds a lot of people use it for a top dressing. But it would seem to me that most of the nutrients would be gone after being boiled and diluted in water. When you boil potatoes are vegetables do you save the water for your worms or garden. I would imagine most of the nutrients are gone then.

By: Bentley

Bentley — Mon, 13 Jul 2009 03:18:34 +0000

Interesting thoughts everyone – thanks for sharing!
ZEB – I think your ‘theory’ definitely holds water, unlike coffee grounds (haha). If you can keep the grounds wet AND let them age, the worms should feed on them. Right?
I am putting this to the test right now. I’ve left a bunch of grounds to sit for a couple months now out in my backyard. Today I totally soaked a tub full of the material and made little ‘coffee pockets’ in various locations in one of my vermi-trenches. I’ll be interested to see how quickly the worms start feeding on the grounds.

By: Zeb

Zeb — Sun, 12 Jul 2009 12:06:14 +0000

I’m an indoor vermiculture novice, but here’s my theory which I’m 99% positive on:

Coffee grounds are almost surgically sterile after being brewed with scalding water. I mean how do you disinfect something? Boil it in water. This is the problem because as we all know: worms thrive on the gunk eating the food, not the food.

So you need to let the coffee re-populate a biotic colony before giving it to your worms. Plenty of ways to do this, but you must plan ahead a little. Mix in a bit of finished compost and let the coffee sit a while to get nice and icky. One mans “icky” is another worms “delicious”. Coffee is much slower to rot than normal food stuffs which is why a little pre-treatment will probably do the trick.