Vermicomposting (Worm Farming) - an introduction

If I was limited to only promoting one single idea on gardening, it would be vermicomposting aka worm farming.  There are so many benefits to this that I nearly get writers block trying to sort the information into a good starting point.

I'd read about it several years ago and dabbled ignorantly with it in garden #1 - I saw first hand some of the effects of it while composting with garden #2 - then researched and experimented with it properly before starting this garden. It is currently THE anchor point - the part of my garden experiments that not only makes a lot of what I want to do possible, but also has the biggest impact on running costs, as well as providing a benefit to the rest of the household.

An extreme simplification:  I put garbage in one end, I get fertilizer, pesticide, mulch, and soil amendments out of the other.

It reduces my cost of these things so close to zero, we may as well call it zero.

I'm going to be breaking this down into several posts - this one will deal with basic info and setup, a future post will deal with maintaining, care, and feeding.

It's a process that revolves around 'Eisenia fedida' commonly known as the 'red wriggler' worm in the US.  It's important to point out that this is different from what we commonly call earthworms. These are composting worms. They live in the top few inches of earth, usually in moist debris (whereas the earthworm burrows down into the earth - these are also useful, and should be promoted in the garden, but they are a separate thing).


In optimal conditions the red wriggler can consume up to it's body weight in material per day (although one half is a more realistic expectation).  Although  we generally say 'they eat the trash' what they actually consume are the microorganisms in the material as it breaks down - it's splitting hairs and I only bring it up so people can understand why this composting method doesn't smell, and to bring up one of the strange mysteries of the process: Although the decomposition of organic material produces microorganisms beneficial to plant growth - the castings left behind by the worms will contain 8 times more than their feed.  The physics nut in me though will point out that there seems to be a ratio of around 2 to 1 of feed weight to final castings, so we can apply the law of conservation of energy to explain this.
These castings contain approximately 5 times more nitrogen, 7 times more phosphorous, and 11 times more potassium, 3 times exchangable magnesium, and 1.5 times the calcium  than normal soil. The castings have a balanced PH, and the process by which they're created removes pathogenic bacteria (my son, who shoves EVERYTHING in him mouth could do a handful of it and it would be less harmful than the sand he regularly tries to eat out of the sandbox). In terms of plant growth factors, they've been likened to seaweed.

It outperforms chemical commercial fertilizers, and you can use as much as often as you like because you can't overdose the plants on it - you can't burn their root systems like you can with commercial fertilzers and plant food.  Which makes it not only effective, but idiotproof.

I put it in the soil when I dig it over as an amendment. When all the seedlings in a square are sprouted and at their second leaves I'll mulch with it as it holds moisture very very well while also helping prevent weeds breaking through - while at the same time fertilizing the plants.  It can be combined with water (or slightly more elaborate recipes) to make a compost tea that can be sprayed as a fertilizer for foliage, and at the same time work as a pesticide against a variety of pests (the 'runoff' - excess moisture drained from the farm also bestows these benefits as it's usually water that's steeped in the accumulated castings).

And this is only the benefits to the garden, there are other benefits for the household.

I started looking into this in earnest originally NOT for the garden - or at least the garden was a secondary benefit.  With twins you get two times everything (especially if they're boy/girl) and that means 2 times the 'baby by-products'. Long story short - when you find yourself prioritizing your trash because your bin is filling up too fast - you have the make changes.  I tried flattening out paper goods, which helped but didn't solve the problem. I started adding paper goods to the compost pile of garden #2, which went a little further (as compost should have both nitrogen and carbon inputs - paper goods are a good way of adding the second) - but the process was taking too long.  With a single matured worm bin I was able to dispose of up to a pound of paper goods per day, that's 30lbs per month (yielding some 15lbs of castings per month).

So - how is it done?  How much does it cost? There's a plethora of sites on the web with plans for building your own from rubbermaid containers, wood, just about anything. For use inside or outside.  When I was dabbling I built a small one out of a old bucket that came full of kitty litter. Your level of cost depends on you. Personally this is one area that in hindsight I feel that putting a bit of money out there is a good investment.  You'll save yourself a lot of time, and if you're just starting you can minimize 'newbie error' by using a tried system.

Worm Bin

This is the actual one that I use - it's made by Vermihut and costs around 50 - 75 dollars depending on how many trays you want (mine came with 5). There are others on the market of varying costs - I went for a budget solution and so far it's performed very well.  I recently expanded by bying a second one that is currently being brought up to speed.
You put your scraps and paper bedding in a tray with your worms until it fills, then place a new one on the top. As food is consumed, the worms travel up to the next layer - leaving behind castings.
The excess moisture from watering the system is drained out the spigot and used on the garden.
The method I use for harvesting is to take the bottom tray out, put it on the top, and take the castings from the top and put them in a bucket - any worms left in that top tray will burrow down to avoid the light - if you do this patiently - the worms naturally sort themselves into a lower tray - to which I put back anything unprocessed. I leave the now empty tray on the top, and the process begins anew.

Before I transplanted a tray to my new tower, I had a healthy population that would have me harvesting out the bottom tray once per month for approx. 15lbs of castings - mind you it takes a bit of time to get your bin to 'mature' to this level. Mine took 4 months before my first harvest, 2 months for the second, and I now harvest every month.
Looking at how the system works, we can say that with 5 trays - one tray harvested a month - I'm giving each tray 5 months to work to the bottom, which for me has given me very rich castings and very little unprocessed material.

Worms

It goes without saying you'll need worms.. a goodly amount of worms.  I get my worms from Uncle Jim's Worm Farm.  He has good service, a good price, and he's expanded into worm bins at a competitive price - he also sells the same bin I use at a cost very close to Vermihut's - making him a one - stop - shop.  As a side note his monthly mailing letter is usually pretty informative and funny. One of the few of these I don't flag as 'spam'.

Remember - a worm can eat up to it's body weight in material per day.  But a worm is really really small.  A rough estimate is around 1000 worms weigh a pound. Depending on how much waste you process and how fast you want your population to mature - I'd suggest getting between 500 and 1000 (I started with 500, in hindsight I would have chosen 1000).  Your 'farm' is just that - and your worms are a 'livestock' - they will breed in favorable conditions and the population will adjust to their surrounds.  Worms tend to congregate and breed in a biomass. so the better the mass, the better your breeding - this is why 500 is a good minimum start point. They are hermaphroditic and require 2 to mate.  The cocoons they lay will produce anywhere up to 20 worms, and in a couple of months these will in turn mature to breeding age.

A quick bit of fuzzy math will give you the population of my first bin. Given 15lbs of casting per month and the approximation of 2-1 feed to castings yields approx 30lbs of garbage input. A worm eats up to it's weight per day - so approx 1lb per day = 1lbs of worms - OPTIMALLY, given things are not optimal we can say anywhere from 1/2lb per day to 1lbs .. so 1000 worms to a lb = between 1000 - 2000 worms.  That's a bit more than the 500 I originally bought less than a year ago.

Besides worms and a bin for them to live in, there are few things that will help you along.  Although not 100% needed, they are worthy investments and you'll wonder how you ever got by without them.

Coconut Coir.

If you buy a worm farm, chances are you're going to be getting a brick included.  It's from the fibers between the flesh and hard shell of coconuts and is used in a variety of products. For our purposes it's a replacement for peat moss that has no bacteria or fungal spores associated with it, it also repels snails.
For our purposes it's an additive to the worm farm used to add more 'green' material when garden/kitchen scraps are unavailable, to remove excess moisture if the bin gets too wet, or as a bedding cover if overfeeding has attracted undesirables like fruit flies to the bin.
It expands in water to 7-8 times its volume - making it easy to store and easy to use. This trait also appears to pass on to the castings produced - and the castings I've made where coir has been present has absorbed and retained more moisture in the garden.  I buy it in 650gram blocks, which expands to about 'a bucket full' with a gallon and a half of water.  Shop around on the web for it and you can get some good deals - the last time I bought 10 blocks - 5 of them have lasted me nearly a year.  I purchased them for around 1.50c per block (plus nearly that in shipping) - shop around for a good deal.
Apart from use with the worm farm, coir is a good addition to your soil, adding a light fluffiness that you find usually from adding peat moss.  I'm using it as the main part of a mix for growing potatoes in.


Paper Shredder

Actually this is the exact model I bought - a 6 sheet cross cut shredder.  This was a recent addition, before that I cut my paper and cardboard by hand. I have only 2 regrets. The first is that I didn't buy one sooner and that I went with the 6 sheet over the 8 sheet.  At Walmart it cost around 45 dollars.
The benefits were 2 fold - firstly was time. as I shred 90% of all paper goods and packaging in the house, and a family of 5 - by hand I would sit at the desk in my office with a box cutter and a pair of scissors and start a movie on netflix.
Since then I get through my bi-weekly shredding in about 5 minutes.  That's a HUGE savings in time.
Secondly the cross cut cardboard and paper is a LOT fluffier and lighter, making it less prone to compaction in the bin, and smaller - providing more surface area (which means a faster break down time).  If you take this on as a regular part of your garden composting - you are going to want to buy one.  Mine is a Fellowes and I'd recommend it - it has an auto shutoff if it overheats,  and handles everything up to a packing box in thickness (thicker packing boxes it does grind and complain, but does the job - see AUTO SHUTOFF on overheating).


Lastly - I'd recommend a bag of corn mean - it makes a nice dietary suppliment for the worms. I got a bag for a buck and I'm still using the same bag a year later - every now and then I sprinkle the top of the tub for a special treat for the little critters.

That's about it for basic info and setup - In a couple of days I'll go over starting, care and feeding.