Do Worms Eat Coffee Grounds?

Most of us need that daily boost of caffeine to help wake us up in the morning, or keep us going throughout the day.

Coffee is a basic item found in most households and even your local coffee shop will usually be happy to help out by giving you their used coffee grounds (if another vermicomposting fanatic hasn’t got there first!)

The coffee industry itself has only grown over the years, thanks to big chains placing new shops all over the world. With the increase in popularity of coffee, what can we do with that extra waste? One way to properly dispose of coffee grounds is with the help of worms.

That’s right, worms eat coffee grounds. Coffee grounds have also become quite a ‘super material’ to have mixed in with your compost.

It’s a great natural way of dealing with the waste that only enriches our planet. Using coffee grounds could make a tasty treat for your red worms!

Do worms like coffee grounds?

Yes, worms do like coffee grounds. In fact, if we are to believe a large number of worm farmers, then we can trust that worms love used coffee grounds!

As a matter of fact, should you have an outdoor worm bin or a regular compost pile, it is suggested to line the compost pile with coffee grounds, for the main purpose of attracting the earthworms to the compost. 

They also seem to like all sorts of coffee grounds. Maybe you like flavored coffee, like caramel coffee, fruity coffee, chocolate coffee, etc.

TIP: just be careful of high sugar content if you add sugar to your coffee. A bit of sugar is fine, but too much may cause foods to rot faster in your bin than worms can eat, causing extra bacteria, nasty smells and increase the acidity of your composting bin!

As it turns out, your worms may like your coffee just as much as you do. They’re not that fussy when it comes to food scraps or organic matter.

No matter what it has been flavored with, coffee grounds remain an organic source of feed for the worms and they will rush towards it.

That being said, as with all things, there needs to be a balance. You may find that your worms are avoiding the coffee grounds and even seem to be reacting badly to them.

If this is the case, then the chances are that you may have simply put too many coffee grounds in.

Although, yes, they are a great source of food and are suitable bedding, too much can be a very bad thing, for a couple of reasons:

  • Coffee grounds absorb moisture superbly. Having foodstuffs that absorb moisture in a worm bin is generally seen as being a good thing, as they keep the bin nice and damp.
  • That being said, should you place too many coffee grounds within the worm farm, then they could eventually absorb most of the moisture coming from the other foods and bedding, leaving the environment far too dry for your worms.
  • Coffee, as we all know, is a very acidic drink. Many of us find ourselves having to add sugar and milk just to make the taste bearable! Too much acidity is very bad for the worms. It could kill them.
  • Small amounts won’t harm them and they will love it, but do keep an eye on your worms over the course of the days following your coffee ground deposit in the bin, just to make sure that they are responding to it healthily and not trying to escape.
  • Should you find that they are not responding well to the coffee grounds, then try adding some ground up eggshells to balance out the acidity level, along with other foodstuffs for a change.

Are coffee grounds good worm food?

Coffee grounds are indeed good worm food. In fact, they are a great source of food for worms, for multiple reasons: 

  • First of all, the taste. Worms are clearly attracted to coffee grounds and, although there is no possible way for us to question them personally about their choices in food, it can be assumed that they choose this food over others a great deal thanks to the taste.

Some believe that it may be the caffeine in coffee grounds that are what are attractive to the worms, but we do not, at least for now, know if that is the whole truth.

  • Coffee grounds are gritty. As odd as it may seem, grittiness is a huge bonus for the worms.

As you know, a worm’s digestive system is quite different from ours, and they need gritty foods, such as coffee grounds, in order to help their gizzards to digest their food.

The gizzard ultimately grinds up the food which later becomes castings (i.e. worm poop). 

  • Coffee grounds remain quite soft as well as being gritty and they break up easily, making them easy for the worms to live within and cross over.
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Worms have particularly fragile skin and anything sharp or rough could harm or even kill them.

Damp coffee grounds have a feel that is comparable to eating soil, which as we know, is the ideal setting for a worm.

They will feel right at home in the coffee grounds and be well nourished by feeding on them. 

  • Lastly, moisture is always a good thing (but a wet environment isn’t!).

Worms absolutely need a damp environment in order to survive. They breathe through their skin and so a dry area will simply not do.

If they feel that the area in which they have found themselves is too dry, then they will do their best to leave.

Should they be in a worm bin or a vermicomposting system, then obviously their chances of leaving are very small and so they run the risk of dying within the bin.

Coffee grounds retain moisture and hold water very well, guaranteeing a nice, damp environment for the worms. 

There are most likely, of course, many other reasons as to why worms like to eat coffee grounds, but these few should leave you happy with the notion that the worms do indeed like them and that you will only be helping our precious planet by disposing of them this way.

Do worms eat coffee filters?

Yes, worms do eat coffee filters. Worm bedding is usually made up of shredded paper and cardboard, so coffee filters are a fine addition to any worm bin/farm.

The worms will happily burrow within it and eat their way through it, as they do with all of their different types of bedding.

Want to know more about other bits and pieces you can add to worm composting? Check out our guide on whether or not you can use bananas in your worm bin.