Monday, 28 January 2013

Hot composting


Hot composting is recommended in large piles (1 – 1.5 meters), but I find it works in much smaller piles and I generally have 2 piles on the go at any one time.

It’s basically a layering effect of carbon, nitrogen, carbon, nitrogen.  Think lasagne.  Ultimately you are looking for a carbon to nitrogen ratio of 25-30:1.

Here is a table to use, there is heaps of this kind of thing on the internet also, although they often differ in values!

Carbon
Nitrogen
 
Fresh leaves, 37:1
Laying poultry manure 6:1
General food waste 15:1
Dry, fallen leaves 47:1
Poultry manure 10:1
Coffee grounds 14:1
Straw/hay 53:1
Diary cow manure 13:1
Weeds 19:1
Newspaper 54:1
Cattle manure 17:1
Seaweed 10:1
Shredded office paper 129:1
Horse manure 27:1
Clover 23:1
Shredded cardboard 378:1
Urine (human) 7:1
Alphalfa 12:1
Sawdust 325:1
Ash 25:1
 
Old compost 40:1
Fish 7:1
 
Pine needles 80:1
Grass clippings 15:1
 
Corn stalks 75:1
Fruit waste 32:1
 
 
Vegetable waste 11:1
 

 

Here’s an online calculator to help you get your quantities right J

http://www.klickitatcounty.org/solidwaste/fileshtml/organics/compostcalc.htm

Combine in layers, adding water as you go, so it’s moist not soggy.  Cover (plastic sheet or tarp or carpet) – leave for 4 days.  Turn with a garden fork – the outside will be the least hot so pop that in the middle.  You need to aerate.  Add water as it dries out, again keep moist not soggy.  Turn every 2-3 days after that, from 1 patch of ground, to another right next to it.  It should feel warm – especially on the inside.  If it isn’t add more nitrogen and remember to keep it moist.  It breaks down much more quickly if you turn every few days.  I usually select a spot I am going to grow in and when its done the area is full of worms.

 

A few things that can kick start a cold heap are comfrey, nettles, urine, dandelion, stinging nettle, yarrow, old compost, seaweed.  Someone suggested a dead possum but I’m not sure how nice that would be with the regular turning!  Don’t use  woody garden clippings, branches etc, they take too long to break down.  Avoid adding bulbs, and I wouldn’t add oxalis or any other root weed.  Dont add animal droppings (from cats or dogs - farm animals are fine), salt, oil or manures from wormed animals.  I’d also don’t recommend any fungus invaded leaves (black spot from roses) or anything with a herbicide or pesticide or weed killer.

I usually get new soil in about 6 weeks.  Good luck!!