I've decided to slowly bring here some of the content from my blog and newsletter.
Today, I'm posting a newsletter article I've written following a question sent to me by one of the newsletter members:

Colin Pearce, has emailed me this week asking for some "stupid questions" regarding his worm farming practices.

There is no stupid questions and it is smart to question our own knowledge and ask for confirmation. With all the misinformation out there on the Internet, it is quite common to see long time worm farmers using the wrong practices. I'm not claiming that what I do is the only way but I've learned a lot from my mistakes and from others' and came to realise that a lot of advice found on the Web can sometimes lead to a catastrophy.

The reason is a lot of things related to worm farming are 'it depends' kind of things. Someone chose the fast and easy way to manage a worm farm and noticed it worked fine for them and started blogging/vlogging about it and the info spread like wild fire. Amongst those who replicate the technique and failed, not many talked about it in public or don't even know that their failure came from those wrong advice.

Among the wrong or misleading info out there:

worms can eat their weight in food waste per day. Although it is possible, this requires from us to reach and maintain ideal conditions at all time. In practice worms eat their weight in food waste and bedding materials (newspaper, carboard, egg boxes etc...) per week.
have you seen those video ads where they try to sell super sexy worm bins and you see the person add of food and get a finished compost in 2 days? No way.
buy a commercial compost bin and chances are the printed guide will tell you to use a watering can and water the bin to create liquid fertiliser (leachate). See my response below.
those printed guides sometimes tell you that you need to buy peat moss or coco coir (theirs of course) to use as bedding material. That's wrong. Firstly the production peat moss is not sustainable (Google it). Then coco coir can contain salt and needs to be rinced before adding to a worm farm. But why buy when the purpose of a worm bin is to recycle materials? Newspaper, corrugated cardboard (bottle shop) and egg boxes can be obtained for free and are excellent bedding materials. Nowadays, in many countries, ink used on newspapers are soy based and the glue on cardboard are corn/starch based.

Here is Colin's initial email:

Love your newsletter

I have a rectangular box type three drawer worm farm
The worms consume the veggie scraps very quickly which I vitamise.

Anyway, feeding that, paper and straw and wool is all fine.
The only thing I know about using the by-product is watering down the leakage from the tap and putting on the plants. You seem to say that's pointless.

When I get a build up of castings I top up the pot plants but it goes white and hard.

Sos basically what am I supposed to do with my worm farm if everything I do so far is what you call 'wrong'?

Love your work.
Cheers

This is a very typical scenario. I myself did this for almost two years, except for blending the food scraps (too lazy lol). And here what I think about those points now.

First, what Colin is doing is not necessarily wrong, but either unnecessary, painful or risky.

1. Vitamising

Blending food scraps is not necessary. It is true it helps bacteria breaking down the food and speed up consumption by the worms. But long term, it will only save you one week worth per bin. Bacteria take about a week to break down the scraps to become worm ready. The worms them take a week to consume them (if not overfed). So by blending you save the first week. By feeding half bin once a week it helps you compensate for the one week bacteria process:

week one bacteria break down
week two worms start eating but you give new food on the other half and bacteria start their job there
repeat

So you only "waste" the first week but save a lot of your time not blending. It's a bit hard to explain so maybe the comparison diagram below will help understand.

Compost worms feeding diagram

2. The leachate

Leachate is what is commonly (but wrongly) refered as worm tea or worm wee. However, it is neither a tea nor worm's urine.

Using the leachate that leaks at the bottom isn't pointless but risky. It does contain a lot of the nutrient from the VC the water went through but also uncomposted food micro-particles and potentially phytotoxic (toxic for plants) compounds. This is why if one insist on using leachate, one should dilute 1:10 with water. You force leachate formation by overwatering the bin. If done when there are no fresh food then the leachate is a bit safer, however you are creating a wet environment inside a bin (I assume plastic) that does not promote great aeration and thus will stay wet very long. This long term wetness will potentially create an anaerobic environment where "bad" bacteria will breed. So to finish, not only leachate is risky, it also takes away all the good stuffs from your final compost. I it's much better to harvest some finish compost and make a compost tea or aerated compost tea.

3. Vermiconcrete

Or worm compost going hard as rock. This is the result of overwatering the wormbin by manually adding water or feeding the worms with food scraps without adding enough dry bedding materials (cardboard, newspaper, egg boxes,,,) to absorb excess water. Blending food also contributes to leaching the food moisture faster. The result is very wet/muddy castings at the bottom that is difficult to work with, and difficult to separate worms and cocoons from it. Best is to control moisture from day one with adding a lot of bedding material at every feeding. But if you already have the issue then you might want to dry the muddy VC by mixing in some dry bedding material, or let it dry in open air and fluffing regularly until it get to a good moist consistency. The added bedding material can be added to the garden where it will be a good reserve of organic carbon rich material that will become food for the micro organisms.

Coling, then, followed with an extra question:

If I harvest from the middle box, the castings are full of worms taking a break from eating. I don't want to throw them away.
There's not much in the lower box: mud at best ( which I will address when I put your advice to work of course)
So which bit do I harvest and how often? How is that for a stupid question from someone who has had a worm farm for five years?

In a stacking system, you only want to harvest the bottom tray, unless you have more than three trays then harvesting the one before last could be done if the trays are deep enough. The reason being you want to give the compost enough time to mature and most cocoons to hatch and worms to migrate upwards.

From the book "Vermiculture. Technology. Earthworms, Organic Wastes, and Environmental Management. by Clive A. Edwards" (considered a bible) the recommended time from start to harvest for a domestic system (like Can-O-Worms, Worm Factory, WF 360 etc...) is 120 days. This time also allows all pathogens to be killed by the worms and other beneficial organisms in the bin. It also allows most cocoons to hatch and most worms to migrate to upper trays.

This is why Colin's middle box is full of worms. They are actually not taking a break from eating, but the VC in that section still contains edible microparticles, worsen by a regular leaching of the top tray. So the worms have a nice compost to live in and they are sustained by the leaching food. Another good reason to control moisture added to the feeding tray.

That's it for this time. Thank you Colin for letting me use your questions for this newsletter. I think it will help others too.

If you guys want more info on good worm farming practices, don't forget to download these free eBooks available in PDF:

Source: The Little Worm Farm's Newsletter - Are you doing it right?