Thursday, 12 May 2016

Tumbleweed Can-O-Worms review

This is the first review on this blog. I'll update it with pictures when I have time.

I have had this bin for 2 years now and it has produced a lot of castings for me, in a small space, and consumed countless buckets of food scraps and cardboard.


Pretty easy. The instructions tell you to put the packaging at the bottom of the bottom tray. I found this coated cardboard didn't break down after a year at the bottom of the farm. It's good to put something at the bottom to keep the bedding from falling through the holes too much but this packaging cardboard probably restricts airflow. So probably better to use something more permeable like a few layers of newspaper.

I had also purchased two worm blankets. In practice I found the worm blanket to become a hassle after a while. Initially it's easy to remove but eventually the worms start to live in the blanket and fill it with castings, it gets several inches thick and really heavy, and eventually breaks apart (but doesn't actually break down very fast after that). Better to just keep the farm topped with a layer of say, shredded newspaper or cardboard and during warmer months at least, make sure it's in the shade (I cover mine with a tarp in summer and year round with shade cloth and they have survived 37 C highs and -8 C lows).

The Australian model comes with two trays, I have seen the US model come with three. I purchased a third tray. More is not recommended as it might become too heavy for the plastic legs.


At first it may be advantageous to cut your scraps up a bit more for the worms. I've even seen people put them in a blender or food processor. However, once you have a large worm population, especially in the warmer months, the worms eat very fast (helped probably by the warmer temperatures breaking the food down faster). I've put a heavy compost bin full of coarse scraps in there and had it disappear in a few days. It might not be a bad idea in winter though, but I don't usually bother. I will usually coarsely chop large scraps (like watermelon rinds) before I throw them in the compost bin though. I don't put in citrus but I doubt it is harmful in small amounts - the worms will avoid things they don't like until they are sufficiently broken down enough to eat. Many seeds will germinate inside the worm bin and because of this, they are safe to include. This includes things like pumpkin and cucumbers. Others, especially those that require light to germinate, you are probably best avoiding putting in as these will likely stay dormant and then pop up as "volunteers" (ie. weeds) in the garden bed later.

Make sure to include "grits" like a handful of sandy soil now and again, coffee grounds and ground up eggshells. I let my eggshells dry (after rubbing off the egg white residue on the inside under running water, which is where salmonella can breed) and then grind them up in a mortar and pestle.

I also add shredded and soaked cardboard on top after each feeding. I got a shredder from Officeworks (Ledah PX880) which importantly is rated for corrugated (packaging) cardboard (many paper shredders say they don't do cardboard, although thin cardboard probably works) and also cross cuts into small pieces, so it's perfect for this purpose.


I'll describe what I've found be the best harvesting method for this type of multi-tray bin. If you just need a few scoops for potting or planting hole, you can lift off the top tray and scrape some off the top of the tray below. During warmer months, there are more worms in the lower layers likely because it's cooler there but during the cooler months, most of the worms are actually in the upper tray where the decomposing matter provides warmth as well as food.

Before harvesting, don't feed and definitely don't water the worm farm for at least a week. Leave the spigot open so the worm farm is well drained. I usually dilute this runoff or "lechate" and use it on hardy non-edibles like the hedge. Letting your worm farm dry out a bit will mean the castings are more "fluffy" and less sticky and gluggy which makes them a lot easier to harvest. It will also make the trays less heavy - they can be very heavy if water logged, especially if you are moving more than one at a time.

I've read a lot of harvesting guides that say if you feed before harvesting "most" of the worms will then congregate around the new food. This hasn't been my experience - at least in the warmer months, as stated above. So you can't really count on the lower trays to be free of worms. Nor am I a fan of dumping out castings on a tarp and making a worm poop pyramid - not when you have multiple trays you can take advantage of. So I'll describe what works for me and it's relatively mess-free.

Harvest on sunny but calm day. The sunnier it is (in terms of brightness, not heat) the easier it will be. First, take the top (feeding or working) tray out and place it on a work table or tarp of some sort. Then take the tray you want to harvest out and place it on top of this tray. I have three trays - if you only have two, what you can easily do is take out your full (bottom) tray and then place the working (top) tray back onto the base. Then place the full tray back on top of this. This will allow the worms to escape back into the lower tray as you harvest.

It shouldn't take long that any worms near the surface will burrow down to escape the light. Now take your trowel and scrape off a layer of castings into another container. You will expose some worms, who will then burrow down further. Keep going until you reach the bottom - at which point most of the worms will have escaped into the tray below, where you want them, or be clustered in the corners. If you only have the two trays - you're done. And your now near empty tray is your new working tray. If you have three trays, you can now invert this tray and dump out any remaining large scraps/worms into the tray below and then grab the second full tray and place it back on top of your working tray and continue. When you are done, the fullest tray should go on the bottom and the emptiest on top. If you keep the harvested castings outside cover them. If they get rained on they become a bit like poop jelly and are harder to mix into soil or potting mix.


I have at different times had infestations of red/brown soil mites, springtails, soldier fly larvae and so on. Generally you don't need to worry about them as they respond to favourable temperatures/conditions and then decline when they change and help in breaking things down anyway. Do add garden lime or "worm farm conditioner" every few weeks (ground eggshells serve the same purpose) or if the worm farm starts smelling sour, as well as aerating the surface a bit. When I open the bin generally a few hatched black soldier fly will make their long awaited escape. They are harmless and do not bite or sting. The base also accumulates castings over time so a yearly hose out (over a lawn or garden bed, preferably) is a good idea, as well as the lid especially if the ventilation holes become clogged with castings or mite eggs. In summer during heat waves you may need to water the farm occasionally, just run water through it with a gentle shower from the hose and then use the runoff to water the lawn or trees (probably not a good idea straight on the vegie bed). Feed less and more often if possible during very warm weather as large amounts of decomposing food will also add heat to the farm. I have had the farm overheat on occasion from this (also being late to cover it with the tarp when we had our first really warm spring days) and the smell is unpleasant to say the least, and the worms didn't enjoy it much either, poor buggers.


Well, that's about it. It's a good product and produces great castings out of your kitchen scraps. If I had the space or budget and my time over I'd probably have gone a continuous flow system like the "Hungry Bin", but you're still going to get runoff, have some heat/pest problems and you still need to scrape the castings out from the bottom, so it's still messy - not to mention a lot more expensive. But it would mean less lifting and shuffling of heavy tubs of castings.

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