Friday, February 4, 2011

Peat Moss and Worm Bedding

One of the most frequent misunderstandings about worm farming and vermicomposting concerns the use of peat moss as worm bedding   Today, the issue has come up twice from two of my customers.  One question was about  the type of peat moss and the other question was about the age of the peat moss bedding.

What Kind of Peat Moss Is Best?

When using peat moss in your worm beds, DO NOT use peat moss that contains additives such as fertilizer.  Miracle Grow peat moss has fertilizer added to it and cannot be used for worm bedding.  The fertilizer will kill your worms. 

Look for Canadian Sphagnum Peat Moss for your worm bedding.  It is naturally organic and has not had anything added to it that will harm your worms. Dry peat moss, however, has an acid pH, which is not a good thing.  To lower the pH towards neutral, dampen the peat moss and let it sit for at least 24-36 hours before adding your worms.

Can You Just Use Peat Moss As The Only Worm Bedding Ingredient?

Yes, you can use just peat moss.  BUT, you must change out the peat moss every 14 days to prevent protein poisoning from occurring in your worms and killing them.  That's the reason peat moss by itself is usually used for short term holding and shipping.

If you are trying to grow and breed worms,  it isn't practical to change the bedding this often.  For long term holding, breeding and growing worms, mix something else with the peat moss.  Use a ratio of 50:50 - that is 50% or less peat moss and 50% or more of any of the following:
  • shredded and dampened newspaper or other paper
  • shredded and dampened cardboard
  • aged horse manure (with or without stall bedding)
  • aged and dampened saw dust
Dampen all worm bedding ingredients and let it sit for at least 36 hours.  Check the worm bedding mixture often to see the moisture content, pH level, and temperature. If items such as horse manure or wood chips aren't properly aged, they may "heat-up" and kill your worms. Make sure the ingredients are well past the "heating-up" stage before introducing your precious worms to it.

Worm Bedding Tip:

Always add a few worms to a small amount of the new mix to see how the worms fare.  This way, you won't kill off all your worms should the worm bedding contain something harmful that you aren't aware of.

And always change out your worm bedding when it becomes too concentrated with worm castings.  When and how often is determined how many worms you have and how much worm bedding.  The more worms in the bedding, the more often you need to change it.

If you have any questions about worm bedding, please post them in the comments. 

Worm Bedding Resources:

For more worm bedding and worm bedding maintenance tip's and how-to's, check out my "Worm Farm Manual: A Step-by-Step Guide to Raising Earthworms" .


  1. You said above that you have to mix the peat moss with 50% something else, what about coconut coir mixed with the peat? Will that work as the other 50% of the bedding?

    1. Yes, you could do that. Make sure the coconut coir isn't full of salt. You can also just use plain coir, but it's expensive. Good luck!

    2. Coconut Coir is naturally high in salt, since it's harvested by soaking in salt water lagoons. Be sure to flush it well before use, either as worm bedding or for planting material. Plants will take up the salt in the place of potassium, or be stunted in other ways.