When your Carbon : Nitrogen : Potassium ratio is all to pot (in yer rot)

So how had the Olde Cold Heap been working out for me? Turns out I had some major flaws in my chuck and leave approach to composting. The major ones were leaching and carbon content.

My heaps are not covered and the rain runs right through them. The leachate running off will contain many goodies my garden would benefit from more than my path. Fancy that. The compost I use now, when it is ready, is brilliant for growing leafy vegetables – not so brilliant for fruiting like, tomatoes or beans (great humungous leafs though!). After a couple of years of this I realised I needed help.

First up, apparently, I needed to improve the balance of carbon to nitrogen in my mix.
In general Nitrogen is your green (rich and wet) plant material, food scraps, fresh prunings and hedge clippings, leaves, annual weeds and animal manure. Take note with animal manure such as horse, cow or zoo-poo that the animals have not been recently drenched as this will knock your worms about. Your pony-on-grass-poo is good but use your race-horse poo with caution (that is if you want racing worms). Also make sure you have had your tetanus booster especially if you are using horse poo. Tetanus bacteria can be found in any soil where there have been horses (pooping) any time in the past 100 years. So except for a few acres of conservation estate that you probably wouldn't be composting in anyway, that's pretty much everywhere in New Zealand.

Your carbon, in general, is your dry and brown material: pea straw, hay (from the stack bottom, alphapha lucerne and any dried out (formerly) green plant stuff. You can also include cardboard, chipped wood (thin layer) or saw dust (fine layer), paper (not coloured), office paper (quite acidic so not too much), charcoal (such as bio-char – see terra preta soils). Note ash can be a useful addition to your compost as it is usually high in potassium. (Pot. Ash) But note don't count it in your carbon ratio as the carbon has burnt off! (makes sense when you think about it)

Correct ratios. You will sometimes see the ratio written as ⅔ Carbon to ⅓ Nitrogen or C: N 30:10. What this may translate to in your compost heap is roughly (one hand height) 5-10cm layer of Nitrogen to (three hand heights) 8-15 cm layer of Carbon.

Get it right - Too much nitrogen will turn your heap into a smelly slime pit, which Fungus the Bogeyman might like, but unless you are Mrs Fungus the Bogeyman, you probably will not. Too much carbon (too brown and dry) will attract mice. If your heap dries out and gets too dry also be aware of legionella spores which can be deadly if inhaled.