Making compost lasagne

One of the key principles of both organic and permaculture farming is to minimise external inputs to your farming system. Given how important soil is to farming and gardening, growing your own soil is a great strategy. Autumn is an ideal time to get some compost put away for the coming Spring. Whether it’s to top up the garden, or to fill up new garden beds, there’s no such thing as having too much compost under construction. At its simplest, a compost pile uses the same processes as nature to break down organic matter; Bacteria and small critters digest the organic matter, leaving behind rich soil.

Almost any organic matter can be composted, but a few ingredients make the whole process of creating soil that much faster. You can get also get technical with the ratio of carbon to nitrogen in your compost, but experience (and your nose) are really all you need to perfect your technique.

Carbon sources are things like leaves, dried grass or hay, wood chips, or even paper. Nitrogen tends to come from fresh green matter like plants, or animal manures. My favourite ingredients (and what we have to hand) are horse manure from the paddock or stable, old hay, straw from the chicken house, and soil from the last batch of compost as a starter.

We spread the ingredients in fine layers, just like making a lasagne. In the early stages, most of the bacterial activity will happen at the edges of the layers, where the different ingredients meet, so lots of thin layers will compost quicker than a few thick ones. The layers of previous compost act as a starter – providing lots of bacteria to kick-start the composting process.

Here are our latest farm helpers Tanya and Andy, layering up the lasagne. It’s a pleasant morning’s work, building the pile. The individual ingredients don’t smell, and as long as there’s plenty of air getting to the pile, it won’t either.

You can use almost any system to contain the compost. We use some spare boards and some old bits of warratah to retain them. The pile can be open to the weather, but if you’re expecting torrential rain it might pay to cover it with some old carpet. You want the pile moist to do its job, but not soaked.

The chickens quite like helping and will gladly spread the new compost everywhere in search of tasty bugs. I don’t want to deprive them, but that’s why we use the boards – to keep everything in place long enough for it to compost.

After a few days, the pile will start to heat up. That’s a good sign that the compost heap is getting into action. You should be able to put your hand right into the centre without it getting burned (seriously, it can get that hot). If the pile is too hot you’ve probably got too much nitrogenous matter in there, so ease back on the animal manure next time, or add more carbon to the mix. Ideally the pile will get up to 65 degrees C to kill any pathogens or weed seeds in the mix.

In about a month we’ll turn the compost to help aerate it and by Spring there should be a few cubic metres of rich, dark soil to fill up  new garden beds or spread on the pasture – all home grown.

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