This morning, after feeding my little goldfish, Paul, I popped down to the rear of the garden and opened the lid of my compost bin to feed it yet another batch of kitchen scraps. As soon as I opened the bin I could see dozens of little worms greedily, happily wriggling their way through what must seem to them an endless supply of yummy food. "Oh good, we love soybean pods!"
Having just fed Paul, at that moment I wondered whether I also have pet worms? Probably not (calm down!). But I do like and care for the worms with the same enthusiasm that I look after little Paul.
After I settled down from that little buzz of wormth, it did occur to me that my compost bin is half-way between a compost bin and a worm farm. And my secret ingredient is mulch. I think it's time I did some explaining, with pictures to help.
No, this person doesn't have a name, but all
I know that s/he has hundreds of relatives
cohabiting in my tumbler compost bin.
I bought this many years ago, and it is still
working fine. They're not cheap, I think
somewhere around the $175-$200 mark.
There's a lid at both ends, so however many times you spin
it, access is easy enough.
This morning's kitchen scraps includes soybean pods, potato
peelings, orchid flowers, spinach and other salad leftovers.
What's wrong with this is that on its own, this stuff is too 'wet'.
Here's my secret ingredient, the bag of sugar
cane mulch in my shed, 10 feet away from the
compost tumbler bin. I use this because it is
plentiful and relatively cheap.
I grab a good-sized fistful of mulch....
... and sprinkle it over the scraps after I add them. Lid back
on, a couple of tumbles (hopefully spun so that this top end of
the bin ends up down at the bottom afterwards). And spinning
the bin is essential, every time you add scraps, and for us that
means at least three or four times a week. The spinning adds
air to the compost, which speeds up the composting process.
I'm not totally fanatical about adding the
handful of mulch every single time I add the
kitchen scraps, but I do add that handful of mulch
a good majority of the time. The worms love it.
The final thing I should mention about my tumbler bin is that it does have one fairly important drawback to be aware of. It never gets 'hot' like a proper compost heap is meant to – and that means worms thrive but seeds from kitchen scraps such as tomatoes, cucumbers, capsicums etc never cook down. So, the important thing to do with this type of bin is to separate the seeds from the scraps back in the kitchen. We've got into this routine and so it's easy to do. If you don't exclude the seeds, when you spread the mulch you'll get far too many 'volunteer' tomatoes, cucumbers etc sprouting everywhere, and that's more of another weedy pain to remove than anything else.
True compost heaps work on heat to rapidly break down organic matter (and cook all seeds thoroughly). They need to be quite big to do that heat thing properly, about a cubic meter in size – and that's a whopper of a pile of stuff when you think about it.
Here in our small backyard with just the two of us churning out little buckets of scraps daily we're never going to create a cubic meter of stuff to compost down in one go. Very few average backyard gardeners do this. We just add our scraps in dribs and drabs as daily domestic life goes on.
And so our cool little compost tumbler creates beautiful compost, thanks to all that spinning of the bin, plus a mountain of chomping from thousands of worms, but without the dry stuff, the mulch, to balance out the wet scraps, our bin would be an uninhabitable swamp in which few worms could live. With the dry mulch there to balance things out, these worms are like contented cows munching grass in a lush paddock.
Finally, where do the worms come from? The garden. I occasionally add a small spadeful of garden soil to the compost bin. Real garden soil is not just full of worms, it's a whole community of beneficial micro-organisms, and it's a free and fabulous 'compost booster' that is well worth adding to your bin, to get it going well.