High in Carbon - greater than 40:1 carbon to nitrogen ratio
Moisture Retentive - it will absorb and hold moisture
Fluffy or Spongey - it allows for airflow
Free of chemicals, sharp objects, or any other factors that could harm the worms
Examples of common bedding includes:
Coco Coir - I highly recommend for beginners
Finished Worm Castings/Vermicompost - I use this instead of coco coir when its available.
You'll often want to mix these beddings together because they have different strengths and weaknesses, you can read about that in the "How to Make and Use Bedding" section.
Why use Worm Bedding?
Worms cannot live in food scraps alone.
Material like fruit/vegetable waste and coffee grounds, and fresh manure are all
High in Nitrogen
High in Moisture Content
Because those materials are high in nitrogen, they will
Generate Heat from rapid microbial growth
Release all their moisture as they decompose
If there is too much of this material in your bin at once (key word being "too much"), it will
Heat up your bin - which could kill your worms
Release too much moisture - causing the bin to go waterlogged/anaerobic - which could kill your worms
Create foul odors as it decomposes anaerobically
Attract pests like fruit flies
So, we NEED to use bedding because it
is high in carbon, and will not decompose rapidly - it will provide a stable environment
will absorb and hold excess moisture
allow for better airflow, which will help keep the bin aerobic
inhibit odors (if you are feeding worms in the proper amounts there won't be much odor to inhibit, but bedding will help if there ever are odors)
"hide" your worm bin from fruit flies and other pests
Having good bedding in your bin is almost synonymous with having a successful worm farm.
How Much Worm Bedding Do I Need?
You can have up to a 50/50 mix of bedding and food - but not when you first start your bin.
Starting the Bin
When you start, you need to have at least one square foot with at least 3-4 inches depth of bedding for every pound of worms that you have, or plan to have. Your bin will be 100% bedding.
*You could actually keep your bin at 100% bedding if you don't want to add food waste, but you don't
want it to ever be less than 50% bedding.
Maintaining the Bin
Over time as you eventually add approximately an equal amount of food (remember to add food in small amounts at a time) as you initially added bedding, you will want to start to add an equal amount of bedding as food that you add.
For example, say I start my bin with 2.5 gallons of bedding. For the next couple months I add only fruit/vegetable waste. At that point I estimate that my bin has doubled in depth from all the food scraps I have added and is now about 5 gallons of material. This is when I will begin to add additional bedding as I add food scraps to balance the food that I am adding, up to a rate of as much food as bedding.
Of course I am also making sure that I'm aware of the moisture level in my bin, and adding dry bedding to soak up extra water if needed at any point of the process.
How to Make and Use Bedding
If you are worm composting for the first time, you will have such an easier experience if you invest in coco coir just for your first set up. Once you have gotten some experience and are more familiar with how to take care of your worms, you'll want to
Identify which bedding materials are locally available, and free to you.
Be aware of the strengths and weaknesses of those beddings
Create a mix of beddings that will compliment each other
Get them to an appropriate moisture level - only a couple of drops of water should come out when you squeeze it.
Remember that bedding needs to be high in carbon and allow for airflow while maintaining appropriate moisture levels. Individual bedding materials may not be sufficient on their own, and will need to be mixed with others.
Is a great stand-alone bedding.
Provides a lot of airflow and worms love it. The more shredded, the better. The only downside with it is that, although it absorbs a lot of moisture, because it allows for so much airflow it tends to dry out quicker than others, so you might have to add water more often. If you ever need to dry out your bin this is the material to use.
Just make sure you don't add too much. If too much of your bedding is shredded paper, it will clump/mat together and not allow for airflow.
Fall leaves are a great bedding material. Although they are also prone to matting, shredding them will help. They will also not hold moisture as well as other material. Fall leaves will add native microorganisms to your bin, so I would recommend using them, but try to make sure there are no bugs in your leaves when you add them.
Be sure it doesn't have chemical residue on it. These will provide good airflow, but don't absorb moisture as well as other beddings.
This totally depends on how quality the compost is. I tried compost from the dump once and my worms wouldn't even touch it. If its high quality compost, it will be some of the best bedding possible.
This one also has a lot of variables. There can be pests in it, chemicals, etc. But, aged manure can also be some of the best bedding possible. If you are thinking of using aged manure, test a small amount first and gradually add more as you get a feel for if it will work or not.
Only use in very small amounts. Sawdust will also clump/mat and restrict airflow if it is too dense in the worm bin.
You actually can use worm castings or vermicompost (material the worms have mostly eaten) as bedding too.