Friday, May 22, 2009

Worms and Compost

I have been promising to write about compost for a few weeks and once again there was a little prod needed to get me active. The thing is I don’t have an answer. I have been asked about worm farms… (stage whisper) I don’t know the first thing about worms.

Judi wrote

“Good morning Peter, Please can you advise me of a small problem I think I have I have built myself a worm liquid farm from a large council bin, (bought I might add) has been working fantastic until recently, it now is full of a tiny insects. My liquid went from one litre a week of worm liquid down to about 1/4 btl. I take it the insects have something to do with this. Can I spray, it was suggested I use vinegar, but will this affect the worms. Would appreciate your advice."

PLEASE help me. If you know anything about worm farms, let me know.

Why do I link worm farms to compost? My mother in law judges the health of her compost by the worm activity and bans me from putting citrus peel in the compost because it upsets the worms. By contrast my grandfather used to keep an especially rancid compost bin that was almost exclusively lawn clippings, he did keep a beautiful lawn. What’s going on here?

Uncle Dave’s (my grandfather’s name amongst his nursery contemporaries) compost stank because he stewed it. No oxygen could get into the bin with all those fine clippings so the process of breaking the organic material down was painfully slow and the by product was ammonia. Phew!

My mother in law is on the right track. The process of breaking compost down is driven by micro organisms, much smaller than worms. These little guys need air and water and they feed on the organic matter in the compost bin. The bit that I like is they need a balanced diet, that’s why grass clippings alone don’t compost so well. Plus there’s the connection to organic fertilizers, Peter Cundall used to throw heaps of Blood & Bone into his compost mix. Why? Extra nitrogen to encourage the microbes to work harder.

Compost and worms? If the composting process is working optimally, there won’t be any worms living in there. It gets too hot. All those microbes generate a lot of heat, enough in fact to ‘pasteurize’ a lot of bad organisms (including some weed seeds, I’ll get on to just how tough some seeds are one day) out of the compost. Poor old Wilbur Worm wouldn’t cope with a mix that is so hot. A well aerated hot compost mix will also break down more quickly.

On the other hand worms are pretty good at treating soil and organic matter too, so if your compost is supporting a worm community it must be healthy even if it is not quite as efficient as a well aerated compost. Have a look at the Aerobin site, expensive but very clever.

I have some ideas about what is wrong with Judi’s worm farm, but they are guesses. If you know anything please fill me in.
By the way, the pic came from the Foxnews web site and a funny(?) article about gardening replacing Viagra.

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