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Coffee Tips

Do Worms Like Coffee Grounds?

Grounds of Coffee are organic matter, so, they are an ideal food for worms. But, sometimes too much good can be harmful to your worms.

Which means it can be dangerous for your worms. So, “Do worms like coffee grounds?” the answer is simple, yes! they can.

But the thing is not every time. Just like always, there are many things to look at.

worms and coffee grounds.

Likes And Dislikes

There are many opinions about grounds. Worm lovers have been seen having different preferences about coffee grounds. You might be wondering why sometimes worms will go crazy over the beans, and why sometimes ignore it like a rock. Some might avoid all this literally.

Here are some reasons as to why you might be giving up the idea of feeding grounds to your worms.

  • Beans could raise the temperature of the bin/container and kill the worms.
  • Coffee beans are acidic, so the Ph level needs some attention.
  • You can find it difficult to keep it moist. It can get dry forming a crust.
  • It can form anaerobic clumps, as it has fine particles.
  • It rots slower compared to other food.


Some reasons which show coffee beans are a great alternative food for worms in the bin.

  • Worms need to live in moist areas, and beans hold water in them.
  • Has small/fine particles, worms don’t have any teeth. So, it helps them to consume it easily.
  • Grounds are pesticides that will keep any other bugs away.
  • Worms can digest it easily in the gut, as it gives them grit.
  • As we discussed how it can raise the temperature, this can be utilized in winter to maintain temperature.


Benefits of Feeding This Food

Coffee grounds are a natural pesticide. This helps to keep pests like a snail, slugs, and ants at bay. Worms enjoy coffee beans even after brewing. Many fatty acids, proteins, and other carbohydrates are found in the ground which is loved by worms. Worms will mostly prefer old grounds because they will contain a greater number of bacteria.

Worms do not have any teeth. Beans will give worms grit in their gut to cut down on the food. And the small fine particles will also help worms to consume their meal. On plus side, small particles have a good amount of surface area which can create a lot of bacteria for worms.


Raise of Temperature

Grounds are of a green, despite being brown color as they have high levels of nutrition. Just like grass cutting. Coffee grounds have less amount of C: N ratio which raises the temperature in the bin when beans are broken down. This can create a problem for you. So, adding ground to moderation might be a smart choice. This can reduce the rise in temperature to protect your worms. Adding good air ventilation and putting some carbon can also help in maintaining temperature.


It is Acidic

They are a little acidic, when adding make sure they are moist and not dry. But this combo can invite fungi and algae into the bin. Acids can also let pests like pot worms and mites inside. Crushed eggshells or agricultural lime will keep the pH level in control. You can use a pH meter to keep the levels for worms’ survival. The ideal levels are 6-7 for a worm bin.

Amazingly, there was a study a few years back just on feeding coffee beans to worms. It resulted in a high number of deaths mostly because of acidic levels. Putting cardboard in helped to lower the fatality level. Adding some other food resources is not going to do any bad to your worms. So, don’t worry.


Decaf and Chemicals

Chemicals like chlorine are present in tap water in a small amount. This won’t concern your worms. Chlorine fades away as it gets in contact with the sun and air. But if it’s not faded away it can kill or suppress the microorganisms in the bin. And your worms love bacteria’s. If you boil water a little while it can remove up to 30% of the chlorine. Boiling tap water for about 20 minutes will make sure all the chlorine is removed from the water.

Some methods are also used to take out the caffeine from the grounds.

Solvents like water and chemicals are used to do this job. But during the process, you might lose some sugars and proteins too. So, decaf coffee is not the best choice for your pet worms.

Removing with the help of water needs coffee beans to be soaked under hot water. In the chemical method, you are required to soak or wash the beans. Solvents to remove caffeine are methylene chloride or ethyl acetate. But it is not possible for methylene chloride to survive in the roasting process. Ethyl acetate can be found in some fruits like apples, so the worms can eat it easily. So, giving decaf coffee won’t harm worms.


Pre-Composting Grounds

There are more steps involved in the attempt of making coffee ground worm friendly. Worms require bacteria to survive. And after boiling water, most of the required components are gone. And the down point here is, those coffee beans take much longer to go bad than other food. The reason is the low level of cellulose and high sugar and water amount.

So, it’s a smart move to pre-compose your ground for your little friends.

This will invite a large number of bacteria after pre-composed. Fungi and mold will also help to decompose faster.

After a couple of weeks give your worms the decomposed beans. The worms will go crazy to get a piece of their food. Remember to feed them in the pocket method, which means putting the food in different areas so they don’t crowd in one spot.


Some Heads Out for Pre-Composing

Following are the tips for pre-composing coffee grounds.

  • Store them in a bucket and leave them outside till they get moldy.
  • Mix them with once already been pre-composed.
  • Put foods containing high sugar levels like bananas, strawberries, etc.
  • Keep watering the grounds to keep them moist.


How to Feed

Pre-compose your grounds for microbial activity. Only 20-50% of the worm’s diet should be coffee grounds. Start with a small portion as an experiment to see whether the worms enjoy it or not. Don’t forget to use the pocket feeding method to give them space while eating. Add some number of browns like cardboard or paper as coffee grounds are green. If you have used a paper-based coffee filter then add it as a treat. And the most important is to check if the grounds are moist.



So, the question “Do worms like coffee grounds?” Yes! they surely do. Not all the time though. Pre-composting will help get back the bacteria lost while brewing. Also, limit coffee usage as too much can harm them instead of any good. Because too much can impact temperature, moist level, and acidity.


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