Thank you for all your great responses. Many of them have echoed some of my own experiences with worms over the past year. I want to answer
Kamaar as to my production rate of vermicompost.
The amount that I quoted is based on 5 tubs of worms which I am only now scaling up to from 3 tubs. So my existing production during warm months particularly has been about 3 cu.ft. every 3 months. During the scaling up process, my production is reduced which will be self explanatory when I describe how I harvest and seed the new bin. To summarize , however, if I am scaling up the number of bins the worm castings that would be harvested are used to seed the new bin and the number of worms are about half because they are split between the old and the new bin. These two factors combined decimate the harvest and also slow production a bit as the worm density is recovering from the split.
My worm bins are standard 18 gallon (~2.2 cu ft.) Rubbermaid type bins. I am still improving my bin design to keep the worms healthy (year round) and growing but the biggest improvements to my vermicomposting system had to do with two factors, 1) using a particular type of bedding which is conducive to great aeration and 2)adding a "chimney" to the middle of the bin to improve aeration. The chimney is made out of 1/2" hardware cloth rolled into a 2"x12" or 14" roll and covering with an old sock. This provides air to all levels of the bin. The bedding I referred to is shredded cardboard
. I have a medium duty paper shredder and it is not happy about shredding the cardboard but it does it with a bit of complaining. When my worm compost at the bottom of the bin are nearly 100% worm castings I mix in more carboard to allow for better air flow through the material. The cardboard also becomes food as it decomposes. I soak the cardboard in water
and squeeze out the excess before adding it to the bin and mixing it in with the existing castings. I alternate feeding from one end or the other to keep from getting too much organic material in one spot in the bin. This along with good aeration keeps the system well oxygenated and avoids anaerobic situations.
Once the entire bin has been converted to nearly finished castings, I harvest the material. There are a few different methods I have used for separating out the worms from the castings and it would be rather extensive to describe all those processes here, but for sake of this discussion just suffice to say that I encourage the worms to go to one half of the bin and take castings out of the other half. Due to the size of the bins when you get the bins 90% full and harvest half of the material means that each bin provides roughly 1 cu ft of finished castings, and another 1 cu ft of nearly finished castings with a lot of worms in it. I then add enough shredded cardboard to the remaining 1 cu ft. of castings with the worms bring the bulk of the material back up to 2 cu. ft. I am experimenting with adding other organic material along with the cardboard. One of the material streams that I add to the bins is a pile of half composted wood
chips mixed with and half well aged cow manure which was allowed to compost for nearly a year. It is very rich soil and nearly 100% decomposed organic material. I mix in enough of the composted soil to give the worms some food they can access immediately but not so much as to make the material overly dense. As the cardboard decomposes it will naturally get less aerated
as it gets closer to being finished worm castings. Due to my desire to keep the system well aerated, I am willing to have the finished castings with some percentage of not yet fully composted and consumed cardboard. At this stage the small amount of shredded cardboard decomposes into the soil in a couple weeks. This would not works so well if you were selling the worm castings, but as I am using them myself it is not a problem.
By maintaining good aeration and proper moisture with healthy bedding material and nutrition for the worms makes for happy and actively reproducing and growing worms. I am still experimenting with different types of worms and different feed
stocks. As I complete the next two bins (in my current expansion) with all my new vent designs I will add a thread
documenting the complete bin design with photos.
Depending on the temperature of your bins and how optimal all the conditions are for the worms, the bin will complete in 2 to 3 months. As the shredded carboard breaks down and is consumed, the volume naturally contracts. Some of that volume is replaced by the food material which is gradually being added along incremental amounts of additional shredded cardboard. Part of the reason that the material can be harvested every 2-3 months is that I am starting with 50% finished castings at the beginning for the process. It is a lot quicker and easier to go from 50% concentration to 100% concentration than from .1% worm castings to 100%. The 50% castings have a dense concentration of worms in a host material that is very pleasing to the worms and has lots of all the beneficial bacteria and fungi
that are needed to assist the worms in breaking down the material and creating worm castings.
As to William's use of a blender, it certainly helps the worm consume the material more quickly. Another similar technique is to freeze the food prior to putting it into the bin. This also helps to break down the food albeit not quite as quickly as the blender method. I have been focusing on maintaining optimal conditions for healthy worm reproduction and growth. After a couple of major worm die offs, I have learned not to ever overfeed the worms. Give the worms the conditions they need and they will do most of the work for you.
As an aside, I found that some of my bins had a fair number of blue worms in them. I have heard that this is not a problem as the blue worms can also do a decent job
of composting food material. What I found with the blue worms is that they are far more migratory than the red worms, and would congregate in the walls and lids of the bins. So I began collecting them from the lids of all the exiting bins and putting them into a new bin. I am going to compare how well the blue worms compost relative to the red wigglers and the European night crawlers. I will report back in on these things in 6 to 9 months time.
I hope this was somewhat informative if a bit rambling.