2016-10-18 Tue


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For the past six months I have studied the use of Plastic Tubs to introduce Kitchen Scraps into my bin in a measured fashion. It seems to take about three weeks for the Bacteria and Worms to invade the tub and reduce the scraps to unidentifiable bits of brown and black.

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I hit on the idea of a Collapsible tub in the form of a Plastic Mesh Bag used for onions, and a Cone of Newspaper inside the mesh.

In the photo above you see the cone of newspaper inside the mesh bag.

Whereas before I would just drop the plastic tub into the Vermicomposter Bin, today I empty the plastic tub into the cone of paper. That gives me a container that is almost wholly consumable.

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I make a bed of Shredded Paper to catch most of the fluid that will seep out of the mesh bag, and place the bag-and-cone with scraps in the bin. I cover the lot with a scoop of soil, bacteria and worms and leave it be.

In a few weeks time I will lift this first bag to see how much has been consumed.


I have been bothered for more than ten years over this business of “(Red Wriggler) Worms eat their own weight in kitchen scraps every two days”.

The myth is quoted widely and stems from a book “Worms Eat My Garbage” by ??? Nowhere can I find justification for this figure. Nowhere a study.

So a few years back I decided to measure just how much a pound of worms can consume, and ran into a series of road-blocks:-

(1) Worms don’t eat kitchen scraps; worms have no teeth. Worms scrape bacterial film from the surface of kitchen scraps, so the real question is “How quickly can bacteria consume kitchen scraps”? That is, how quickly can a colony of bacteria arise to consume a pound of kitchen scraps at a rate (of population growth) that can be tempered by the growth of the population of worms.

Note that if the worms don’t get in there fast enough, the bacteria will produce a fluid goopy mess of rotting scraps. We need the worms to remove the excess bacteria and slime.

Note that if the worms are too ravenous, they will check the population growth of the bacterial colony, reducing the effectiveness of the bacteria.

(2) We see that with a proper vermicomposting process we must measure the steady-state of the two colonies – bacteria and worms – in a way that the pounds not upset the balance away from a recoverable point.

Clearly if you save up all your scraps for a year and then dump them in the bin, you will have a problem. A monthly dump is probably going to create the same problem. A weekly dump might work, as might a daily dump, but agitating the mix on the hour every hour will probably upset the worms to the point that they slow down their rate of eating and reproduction.

(3) Then there is the definition of “consume”. Coat some fine kitchen scraps with bacteria-laden soil, and within a day, two days at most, the scraps are coated with black soil particles, worm poop, bacteria and so on. The orange peel might be recognizable by its shape, but not by its colour. A shred of lettuce will appear to have disappeared before our eyes – it becomes coated with fine clay and is indistinguishable from the rest of the soil. But can we say that it has been consumed?

(4) I like this thought experiment: Shred a one -pound lettuce and spread the shredded leaves on a table in a dry, shady place. After four days, weight the dried shredded leaves. They will weight about one ounce.

Bingo! Fifteen ounces of lettuce leaf has been consumed by Virtual Worms!

What’s the difference whether the lettuce leaf cells break down to their component parts (mainly water) outside, or inside the vermicomposter. It’s just water anyway, right?

So, about my paper-cone mesh-bag trick. It seems to me that I might weigh my scraps into a mesh cone every Saturday, and then re-weight the bags at intervals to see how quickly each bag reduces to near-zero (the weight of the mesh bag).

Yes, I am including a cone of newspaper to be consumed, but perhaps in this way I can establish an upper-limit on the consumption of kitchen scraps by Red Wriggler worms.