Here is a question from Steve:
I am setting up my first worm bin in an 18 gallon rubbermaid tote. I
have watched your videos and have gained a visual idea but am trying
to get a better understanding of the bedding to waste ratio I should
start with. Thanks.
Great question. If you follow my writing for any length of time (or spend time reading through past posts etc) you’ll discover that I tend to avoid ratios, calculations and really, anything “set in stone” LIKE THE PLAGUE! lol
There are just so many variables involved that it becomes very challenging to come up with “rules” apply to every situation (apart from some of the basic, core fundamentals of vermicomposting, that is).
That being said, as you may recall, I DO provide some rough guidelines regarding the bedding to food ratio in at least one or two of my set-up videos (if I remember correctly) so it’s certainly a topic that can be discussed further. Let’s start with some assumptions.
I’m assuming here that:
1) We’re talking about food wastes as the primary “food” material and absorbent, carbon-rich bedding materials – such as shredded cardboard (my favorite), newsprint, paper etc – as the primary “bedding” materials.
2) The food wastes are fairly bulky (perhaps partially chopped up) – not ground up or blended.
2) We’re talking some sort of enclosed, plastic worm bin (you mentioned having a Rubbermaid bin, so I think that’s on target).
Given the above assumptions, it’s safe to say that I will ALWAYS recommend adding a fair amount MORE bedding than food when first setting up. How much more will depend on the length of time I’ll be leaving the system to age before adding the worms and what quantity of worms I’ll be adding. In one or two of my older set up videos (it’s all a little hazy now – haha) I demonstrated a bedding-food layering approach. Basically, I started and ended with thick bedding layers, while alternating food and bedding layers (approximately the same thickness) in between.
Adding this much food waste (let’s say 25-40% of total volume) might not be the best idea IF we are planning to add the worms fairly soon (within the first 1-5 days or so). I would only recommend this in cases where the bin would be allowed to age for at least 1-2 weeks, OR if we were going to venture away from those assumptions I listed above (eg. if using larger, open systems, different food/bedding materials etc).
It’s also important to point out that one of the key topics left out of those older set up videos is the recommended maintenance activities during the aging period. In a lot of cases, I’m sure you could get away with simply letting the bin sit and then adding the worms – but for best results, I recommend periodically mixing everything up, and adding even more bedding materials (and water if needed) before the worms are added. In other words, even in cases where I am letting a bin age for quite some time and I have added a lot of food waste to start, I will very often increase the quantity of bedding materials over the course of the aging period – effectively increasing that bedding to food ratio.
Bottom-line – assuming you are adding at least some food, and everything ends up nicely moistened (without pooling on the bottom) – there is really no such thing as “too much bedding” or, in your terms, “too high a bedding to food ratio”. If you cornered me and forced me to come up with a firmish recommended ratio (haha), I’d probably say 3:1 (bedding:food volume ratio) and above. A range of 3:1 to 5:1 would probably be a good zone to aim for, especially if you are just starting out. It’s definitely better to err on the side of having “too much” bedding than on the side of having too much food!
What’s really interesting is that almost every single “brand new vermicomposter” worm bin I’ve looked at over the years hasn’t had enough bedding in it! This might help to explain why I tend to be a bit over the top about all this bedding stuff (remember the RWC mantra – “bedding is my friend”!! LOL).
Hope this helps, Steve!