Secrets of compost
May 19, 2020
I don’t compost, as I don’t produce enough material to run a compost heap, weed tea and a worm farm, so what follows is researched info that’s been okayed by some of my gardening friends, Michele, Pete Bufo, and some of their tips from experience.
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Compost has four ingredients
Water. Your compost pile should be moist like a damp sponge, not soggy or waterlogged. Too dry and nothing really happens. Too wet and you get slime.
Air. There needs to be some aeration for the right microbes to live or the whole thing stagnates into a vile pile of anaerobic sludge.
Then two equal groups by volume. Carbon and nitrogen. Or, brown and green. Or, alive and dead. Or, dry and wet.
Carbon (brown / dead / dry) materials. Straw. Brown leaves. Old sawdust. Paper (not the glossy stuff). Pine needles. Wood ash. Molasses. Cardboard (not waxed!)
Nitrogen (green / alive / wet) materials. Seaweed. Green grass clippings (tip – mow before seeds form). Green garden waste (weeds in hot compost only otherwise you just help them spread). Animal manure (c’mon, you know it’s alive!!). Previous compost. Kitchen scraps. Coffee grounds (don’t be fooled by their colour).
Hot compost
This gives the better compost, in a much shorter time frame than cold compost and it kills weeds & their seeds. It requires work. As in daily temperature monitoring, watering, and regular turning the entire pile of minimum one cubic meter. I’m kinda not into hauling materials into a pile, checking daily, turning a huge pile of material and then hauling it all back around the yard again. My back aches just thinking about it! Having said that, hot compost is soil gold. So if a load of shovelling doesn’t put you off, go for it.
Make a pile at least a cubic metre in size (required to generate the heat that does the magic), of equal and alternating layers of carbon and nitrogen, with plenty of water along the way. Find a metal bar or star picket to leave poking out from the middle. If the bar gets too hot to touch, cool the pile with plenty of water. The ideal temperature is 60-65 degrees C. If it’s hotter the good microbes are being killed. You can wiggle the bar around and stab into the pile to help let air in. About every 2-10 days, the pile will start to cool down. Turn the entire pile to really aerate it which will kickstart microbial activity again. Do this for about 3-6 weeks. At the end you will have weed free soil super food.
When earthworms move into the compost, you know it is finished and ready. It will be cooled down and the texture should be crumbly and it should smell almost sweet.
If you’ve seen those ‘compost tumblers’, they are for hot composting. They are designed to be filled in one go, and the tumbling is meant to replace the shovelling. They do work. Research suggests the traditional method with the ingredients touching the ground is better because all sorts of beneficial microbes and helpful critters (worms and friends) can move in. An enclosed tumbler prevents this.
Cold compost
This is the dalek-looking black container that most backyards seem to have. The first step that always seems to be missed is that the bottom needs to be made rodent proof. Get some aviary mesh. Attach it. You can’t keep them out otherwise and a slow cooking compost pile is the perfect home for an extended family of rodents.
Stuff to keep out of your cold compost. Dog & cat poo. Meat and bones. Why? They can harbour diseases that can be passed to humans. While these can be killed by enough heat, cold compost cannot do this.
Also anything thicker than your little finger will take years, YEARS!! to break down in cold compost. Chop things up or make use of them another way. One tip is to put the thick stuff in to help aerate the pile, and sieve it out with chicken wire at the end. Or use it in forest compost (below).
Cold compost uses time rather than heat. The trick is to keep an eye on the ingredients that go in. Whenever you add kitchen scraps (nitrogen), cover them with a similar amount of paper or straw or cardboard (carbon) and give it a drink. This keeps the ingredient ratios about right, and keeping the kitchen scraps covered keeps it from being a magnet for maggot-layers.
It takes 6-12 months before this style of compost is ready. Way less effort, way more time.
After the first 6-12 months there will be a small steady supply of ready compost at the bottom of your bin.
Chop and drop ‘forest compost’
Actually I do compost. This is my style. Some might call it lazy gardening. It can be described as ‘composting in situ’. It’s what the forest does. Branches and leaves compost where they fall, in their own time. The forest has beautiful soil. I like to do this for trees, it isn’t suitable to try and plant veggies around forest compost. Any prunings, I dump around the base of my fruit trees. It’s a slow release feed. This is an easy use of those sticks that are too fat for cold compost.
Worm farms
They don’t actually use regular garden worms because those worms don’t like the high nitrogen environment of the ‘farm’. There are a few varieties that do like this environment, red wrigglers, tiger worms and Indian blues. There are others too. You will need to seek them out from a store or a friend with a worm farm. You don’t actually need to get a huge quantity of worms. If there’s enough food, they will breed to eat it all. But if there’s a tonne more food than worms it will get festy until their numbers have multiplied up enough.
Worm farms can be those plastic multi-level trays you can buy, or a DIY equivalent, or something like an old bathtub. The multi-storey trays separate out worm compost at different stages. This is done in a bathtub by alternating using each end. Add kitchen scraps (nitrogen) and carbon material to one tray layer or bathtub end until full, then move on to the next tray or other end of the tub. The worms will move about the different areas, following the food. Their ‘compost’ is ready when they have (mostly) moved on.
A worm farm set up needs a cover from birds (a lid, or old carpet or layers of cardboard). Rodent proofing is wise. They need shade (don’t cook your worms!). They need water, and also a way for their home to drain freely of too much water so they don’t drown. The drain shouldn’t also drain worms out! I put some shadecloth over the open plughole of the wormbath. That’s enough to keep most of them safe. Keep a bucket under the drain and that’s your liquid fertiliser. I also keep a big bin next to the wormbath for storing the excess worm tea. The bucket under the drain gets emptied into this.
Worm farms are my favourite. They make fabulous compost (in this case worm poo) and liquid fertiliser all in one and easily. Water this down 1 part worm tea to 9 parts water. It’s strong stuff.
Worms don’t like: large amounts of onion, garlic or citrus; corn cobs, corn husks, avocado stones, hair / fur, mango stones, but only because they take ages to break down. Crush eggshells. Small amounts of meat are ok, if the worm farm is rodent proof. Worms love kitchen scraps and office paper work. They actually need a bit of grit (sand or dirt) for their digestion too.
