After writing about earthworms and composting the other week, I read Composting: from organic waste to black gold by Victoria Heywood (Penguin, 2005) and found out I got some things wrong. I thought I’d better correct my mistakes.
I’ve always thought that composting and vermiculture were completely different. I knew in the back of my mind they were both recycling organic matter and thus both composting, but I still thought worm farming was somehow lower on the composting ladder. It may have to do with reading books about composting in a heap, in which earthworms were only one aspect of the process. I’ve now realised they are both equally composting, just different methods to come to the same conclusion. This view may have coloured my statement,
Although Vanessa at Green as a Thistle blogged about making a composting unit, it’s actually a worm farm.
Vanessa probably doesn’t even know my blog exists, but if you happen to read her thoughts as well as mine, I am trying not to be a compost snob. If you read further you will discover I’m not even doing my composting right. I probably should just bury myself in the compost heap right now!
The anaerobic bacteria in the middle of the compost (where there’s no oxygen) generate high temperatures (up to 60ºC).
When composting begins the temperature is about 20-30ºC and mesophilic bacteria (which like medium temperatures) break down the material. They eat and multiply, producing water, carbon dioxide and heat. As the heat increases thermophilic bacteria start working on the material and they like temperatures of 40-70ºC, which is when the compost pile cooks. Both of these are aerobic bacteria and will only live, eat and multiply if there is enough oxygen, hence the need for aeration. Anaerobic bacteria will break down material if there is no oxygen, but you don’t want this happening because they smell bad. Aerating the heap will keep them away.
I also discovered that after the food for these bacteria runs out the temperature decreases and macroscopic critters (earthworms, centipedes and mites) return to do some more eating. But it’s not over yet; the compost is still raw and needs maturation. Victoria Heywood wrote,
Once the worms start to disappear, you know the compost is almost done. At this stage it’s considered ‘cooked’ and ready to use. Your compost should look like rich chocolate cake – dark brown in colour, moist and crumbly.
Yum! So when I’m spreading “compost” on my garden that is full of worms, it’s not actually the finished product. I always thought it didn’t look quite like compost. Because I aerate my compost bin so little it may take years to produce mature compost. I’m going to have to use my spiral compost aerator.
Or you could dig in someone’s garden for the earthworms.
The earthworms you buy to put in a worm farm are not the same as those found in garden soil. Tiger worms or Red Wigglers (Eisenia fetida) and Indian Blues (Perionyx excavatus) have bigger appetites and faster breeding cycles. If you put them in your garden soil they will starve, although you can put them in a compost bin which will have as much food as a worm farm. The earthworms in my garden and compost bin may be Amynthas corticis or Amynthas gracilis, the most common introduced megascolecids found around the world. The Australian Museum tells me I can look at the segments 14-16 to identify them, but the worms and I will both be happier if I skip that and stick to being lazyst.
That’s the end of the corrections, but I did acquire two more pearls of wisdom from Miss Heywood. The first could start me on a hobby even more disgusting than composting – pet poo processing. There is way too much pet poo in my life and I would love an alternative to digging holes in the lawn to bury it. The cats do their own digging, but some of them are not as expert at the actual burying. Digging up the lawn isn’t a problem. It’s just that sometimes (a lot of the time) I’m lazyst and dig in a lawn-free bit to come across a previous burying, which is never pleasant.
The Tumbleweed Pet Poo Converter is a worm farm with poo as the food. I’m so glad I’m not a worm!
There is no difficulty in getting the worms to eat dog droppings. Commercial worm farmers rear their worms on manure. However it is not possible to mix diets. They must be fed exclusively on pet poo. If you want to recycle vegetable scraps you must set up a separate farm.
I told my dad about feeding poo to worm farms and he said he has an empty worm farm (my brother used it when he was a kid). I knew they had a worm farm, but didn’t know they didn’t use it. I’m really going to stop being a compost snob now, because I’ve decided to buy some worms and set up the worm farm with Sheeba’s poo.
I’ve always thought a compost bin should go in a sunny spot. Victoria Heywood set me straight,
It doesn’t matter whether you put your bin in a sunny corner of the yard, or under the shade of a tree. The heat of your pile depends more on what you put in it than the amount of sun it receives each day. In fact, some shade can help protect your compost against drying out in hot weather.
And while I read a book on composting other than my beloved Compost Book, I won’t be disregarding David and Yvonne’s advice, just adding to it. And its not that The Compost Book gave me the wrong information when I read it for my previous post, I just read it incorrectly.