A couple great questions from Robyn this evening…
I am brand new to this and very interested. I’ve already begun collecting kitchen scraps and have been reading through your articles. Perhaps I haven’t come upon the right article but some questions that I have now are:
1) you mention a “decent amount” of food scraps to bedding…what would this be — equal amounts? more food scraps than bedding? And also, are these layered or mixed together?
2) How does one know when the compost is “ready”? In other words when is it ready to put on the houseplants? Also, is this kind of compost ok for container gardening, specifically a tomato plant?
I’m glad you asked these questions because I have little doubt that there are others wondering the same thing! Ok, let’s get to it.
1) I know I tend to be rather vague at times – aside from being the sort of person that just kind of ‘wings it’ a lot of the time, I also really feel strongly about the idea that there are no hard and fast rules for these sorts of things. Every worm composting system is different (there are so many variables involved) so I always recommend that people test these things out for themselves.
That being said, I’m not just going to leave you leave you hanging like that. 😆
I would definitely say the amount of food (volume, that is) you add should be less than the amount of bedding added. [NOTE: Just in case anyone is unsure, I should mention that we are talking here about when you start up a new bin (before worms added) NOT when you are adding materials once your worms are in the system.] Remember that the bedding serves as a protective buffer for your system, absorbing excess moisture and helping to keep the overall C:N ratio in a safe zone (if it gets too low, nitrogen tends to be lost as ammonia gas which can harm your worms). I would still recommend adding a large volume of food scraps though – perhaps 1/2 the volume of the bedding. As for mixing or layering – either/or is fine (I’ve done both), but DO make sure there is a layer of pure bedding material at the bottom since this is where the most moisture will tend to accumulate.
[Update – Mar 26/08: I started a new worm bin today and realized that the amount of food scraps I feel comfortable adding is actually closer to the volume of the bedding than I thought – perhaps 3/4. I used a layering system today – 4 layers of bedding (1st and last – nice and thick), and 3 layers of food scraps]
2) This is another example of something for which there are no hard and fast rules. If you are using some sort of flow-through system it is much easier to know when the material is ready since the worms are continually moving towards the zone with the best food resources, leaving the compost material behind. In the case of a stackable system like the ‘Can O Worms’, the idea is that once your last (upper) tray has been added and fills up, the compost in the lowest tray is probably ready to be used.
In the case of a regular worm bin (a plastic tub, for example) it can be a little bit more of a challenge to know when you can start harvesting. My recommendation is to simply wait until a lot of the material in the bin has a dark, soil-like appearance, with no residual food waste or bedding. If your system is sealed (i.e. no drainage holes), the material near the bottom will likely be quite anaerobic (oxygen deprived) and definitely shouldn’t be used right away. I’d suggest dumping out your bin (preferably on a sheet or mat outside) and breaking up the compost with a garden fork, then leaving it to dry out somewhat. The worms will concentrate down below and the compost can gradually be removed until you are left with partially digested materials (and worms), which can be added to a new system (something you should prepare prior to harvesting.
As for worm castings (vermicompost) being used in container gardening – ABSOLUTELY! The beauty of this type of compost is that a little goes a long way. A small handful placed in the hole when you plant each tomato should make a big difference.
Anyway – hope this helps!