Do Worms Eat Bone Meal? (Can You Compost Bones in a Worm Bin?)

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Worms eat anything organic, and bone meal is organic matter, so yes, worms can eat bone meal.

But worms do not show a particular like or dislike for bone meal.

For this reason, you should only add a small amount of bone meal to your worm bin at a time and monitor the moisture (too dry and they’ll struggle to breathe, too wet and they’ll want to escape!) and pH level of your bin.

So is bone meal suitable for your worm farm?

We had the same question and did some research – let’s give you a definitive and detailed answer to this question and how you can add bone meal to your worm composting.

Can You Feed Bone Meal to Worms?

Whatever you throw into your worm farm becomes part of their environment, so whatever you put in the worm bin should be done with a view to favoring their habitat.

Yes, you can add bone meal to your worms soil and environment.

As mentioned, worms only feed on organic matter, and bones are organic matter which ticks this box.

Synthetic matter or fertilizers have various concentrations of unhelpful chemicals and other ingredients, such as high salt concentration, which can harm worms.

So, most caring worm farmers will only use organic matter when feeding and to raise worms in a healthy environment where they can thrive.

Can You Compost Bones in a Worm Bin?

You can add compost bones to your worm bin, but you need to treat them first (i.e. steam or boil them, so they’re easily broken down by your worms) or crush the bones to speed up decomposition.

Something to be extremely mindful of is that you must strip the bones of all meat, since this can attract pests and foul smells.

A little bit of meat buried under their soil or other organic materials won’t pose a problem, but too much may draw pests and smells to their soil and environment.

What are the Benefits of Bone Meal For Worm Bins?

In summary, the benefits of bone meal for your earthworms are:

  • Bone meal fertilizer increases phosphorus levels in your worm farm

Most bone meal generally has an NPK ratio of 3:15:0. This means that it is low in nitrogen (N), high in phosphorus (P) and contains almost no potassium (K).

  • Balances out other amendments when mixed.

If you’re using high nitrogen materials or fertilizers like cow manure for your bin, mixing bone meal will balance out the nitrogen. This works for other high nitrogen fertilizers or amendments too.

  • Bone meal provides calcium for your worms.

Though worms don’t get too much calcium in the wild, this is a side benefit and isn’t harmful.

Bone meal is high in Phosphorus. Adding some bone meal into your earthworms food supply will add some phosphorus that worms need to grow.

Phosphorus is also responsible for photosynthesis of plants.

Worm poop – also called worm castings – which is the end goal of many earthworm farmers may contain phosphorus, signifying that phosphorus rich material was eaten by your earthworms when feeding.

Bone meal also contains micronutrients like calcium, iron, magnesium, and Zinc that enhance worm growth.

The natural decomposition of bone meal efficiently and effectively feeds worms in the bin for a long time.

Bone meal takes about four months to break down, which is great because it gives your worms consistent supply of nutrients.

So, with bone meal, you don’t have to keep reapplying it every week.

Bone meal is an excellent addition to your worm bin because it is all organic, and worms thrive in organic matter.

How to Make Bone Meal For Your Worms

Don’t let the bones from your kitchen leftovers add to your local landfill.

You can easily make bone meal out of the bones instead of buying a packed bone meal.

Here’s how..


All you need are:

  • bones
  • a pressure cooker
  • a large container
  • a grinder
  • a dehydrator
  • and an effective precision tool to remove fats and meat from the bones.

Once you have these, you can proceed to make your own bone meal at home.

Step-By-Step Guide

There are many ways to make your bone meal at home, but the first two common steps include cleaning the bones and cooking them.

  • If your bones aren’t cooked, cleaning and cooking them can be done simultaneously by boiling them.
  • Boiling the bones normally would take about 6 hours for smaller bones like chicken bones and turkey bones.
  • NOTE: boiling them might take longer than 6 hours for bigger bones like cow bones, and this is where you may involve a pressure cooker.
  • Boiling with a pressure cooker may only take two hours for your bones to be ready.
  • Completely submerge the bones with tap water, set the pressure cooker to the highest setting, and let them boil for two hours.
  • After boiling, you will realize that the smaller bones will fall away when you hold them, but the bigger bones might require a bit of force.

The next two steps involve dehydrating or removing moisture from the bones and pulverizing them into bone meal powder.

Here, you can choose to pulverize first or dehydrate first. Choose whatever works for you.

  • If you choose to pulverize first, you need to first crush the bones into smaller pieces before putting them in a blender.
  • If you choose to dehydrate, you simply need to put the bones in the dehydrator for the dehydration process.
  • After blending the pieces of bones in a blender, you can remove them and pour them into a dish.
  • At this point, the blended bones will still be a little chunky; you can, however, place them in a pestle and mortar for a little more grinding.
  • Grind the bones pieces until they are finely ground.
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Things to Watch Out For When Making and Feeding Bone Meal to Your Composting Worms

Bone meal is also an excellent addition to the worm feed.

  • Bone meal should be used in soil with a pH level under 7.
    Test your earthworm farm before using bone meal. If your soil’s pH level is too alkaline (7 or above), use a different amendment to raise the acidity and lower the pH level.
  • Mix with other amendments if necessary.
    Your worm bins may require amendments that include other necessary nutrients besides phosphorus and calcium.
  • Too much bone meal can harm your worms.
    Too much bone meal in an already highly alkaline bin can push the pH of a bin into unsafe territory. It can also push out other nutrients that your worms need if used in large quantities. Remember that bone meal takes months to break down! NOTE: you should also not
  • Watch out for meat scraps in the bones.
    Make sure you get rid of the scraps to ensure that your compost piles do not smell.
  • Ensure bone meal is in finely powdered form.
    Because worms can only eat small particles of food.
  • In the case of red wrigglers and nightcrawlers, ensure that the bone meal is buried below the surface.
  • They may draw pests and critters to your earthworm farm, even your pets!
    Solve this issue by burying bone meal a little deeper or the best way, make sure your bin isn’t accessible to them. Bone meal can be toxic to pets like cats and dogs.

Every food that you add to the worm bin should be finely ground, or it should at least be in the smallest pieces possible.

NOTE: You can also apply bone meal directly to plants but shouldn’t do this if the soil’s pH level is above 7 (alkaline) as studies show that the phosphorus is unavailable to plants at this pH level.

What are Alternatives to Bone Meal to Feed My Earthworms?

If you don’t need any more phosphorus in your worm bin and already have too many organic materials high in phosphorus, use these alternatives to change your earthworm farms NPK ratio:

  • Bloodmeal: for more Nitrogen (can last about 2 to 3 months)
  • Kelp meal: for more Potassium (can last around 4 months)


Worms are a great way to reduce food waste and provide rich garden compost.

If you eat meat, you can use the bones instead of throwing them away.

You can pile up the bones in your refrigerator, and in a few weeks, you have enough bones for the bin.

A disadvantage to adding bone meal to your soil or manure is if you have dogs that can access your compost pile, but burying them deep enough and cutting off access for the dog to your worm farm, solves this issue.

Bone meal is excellent for raising worms in a bin.

As we have seen, you can make your bone meal home instead of buying the packed one and save some coin.

It is super easy to raise happy worms, especially if you know what you need to add to their food.

Worms, including earthworms, are hungry for your kitchen leftovers, coffee grounds, eggshells, and yes, bones!

Though their favorite food comes from plants, vegetables, fruits, grains, and beans.