Info from the Kaipatiki Project Hot Composting Course

I took the Kaipatiki Project's free hot composting course - it was great.  A highlight was that you can add comfrey as a compost starter - that you can make a fertilizer "stew" of weeds, or seaweed in a barrel of water.  The basic concept was the layering of thin, wetted layers of nitrogen (green stuff, food scraps) and carbon layers (dead stuff like paper, hay, leaves), in a proportion of  30% nitrogen to 70% carbon and then hot composting will begin.  Before the course I had a compost pile which consisted of nearly all nitrogen - so it didn't hot compost - a process which kills bugs, weeds, breaks materials down quickly - and results in balanced compost.  And if you read the list below, there are many minerals and nutrients to be found in different materials! 

This information, like compost - is gold.

For info on the Kaipatiki Project's free composting project (and other cool courses), go here: http://kaipatiki.org.nz/courses

 

What you need

A balance of all 4 elements - air, fire, water, earth

Air: moving inside the heap to help the micro-organisms to breathe

Fire: the creation of heat helps it to break down quickly

Water: helps to increase bacteria and keeps the organic material

soft

Earth: (minerals)

For best results, aim for 70% carbon and 30% nitrogen.


Carbon:  Dry grass, straw, dry leaves, cardboard, newspaper, sawdust

( untreated)

Nitrogen:  Animal manure (except cat and dog), food scraps, weeds (noninvasive),

comfrey leaves, seaweed, fresh grass clippings, coffee

grounds

Suitable bin types

3 bay boxes

Adjoining boxes spaced 1 mtr x 1 mtr x 1 mtr are ideal for building hot compost piles. There is sufficient surface area to obtain height and build up heat. It is also beneficial for flipping and storing

decomposing compost. Aim to turn the pile 'inside out' by moving the outside of the pile to the centre of the new one.

Wire netting with batons

This allows for a moveable compost heap.

Tumbler

Fast breakdown using shredded or fine materials.

Making a hot compost pile

• Choose a shady location to build the pile

• Build directly onto the ground so worms and microorganisms can readily access the pile and begin to colonise

• Recommended size 1 mtr x 1 mtr x 1 mtr. A big heap works better and faster than a small one.

• Begin with sticks as the bottom layer to provide drainage and allow for air movement into the pile

• Work at layering green and brown materials, approx. 15cm deep (depending on material)

• Use a variety of ingredients to obtain nutrient-dense compost - include activators like blood & bone, comfrey leaves, urine, rockdust, stinging nettle.  These can be sprinkled between layers.

• Break up material to help the decomposition process.  Use a mower or shredder for quick results.

• Water each layer.- a dry heap will not decompose

• Add compost from an existing pile - this will add micro-organisms to help get things started

• Place weeds carrying seed or pests at the centre of the pile where the heat is the greatest.  Dead animals can also be added here

• Cover the heap with a lid or a piece of carpet.

Keep your pile going

• The pile will heat up for 2-3 weeks.  Flip at this pointas it begins to cool down.

• Repeat approx. 3 weeks later. At this stage the original materials should not be distinguishable

• The breakdown process will differ between hotter and cooler months - expect it to take longer in winter

• Check the consistency of the decomposing matter as it is being flipped.  Is it smelling sweet and obviously decomposing?

• When flipping, aim to turn the pile 'inside out' by turning the edges of the original pile into the centre of the new pile

Problems can occur if...


1)  If it is too dry materials will remain intact.

2)  If too wet the pile will become smelly. 

Add materials to rebalance the pile when flipping.

Uses

• Add to gardens, trees and shrubs as a top dressing

• Build up raised bed gardens

• Sift and use for making potting mix (add sand or pumice)

• Coarse compost works as a wonderful mulch.  To prevent blackbirds scattering' the compost apply wet barley straw on top.

What to use in your compost layers

Note: Weeds are a good bulk compost ingredient.  If seeding or carrying pests, place in centre of heap where heat is greatest.

alfalfa/clover contains nitrogen, potassium, phosphorus

banana plants the leaves, trimmings, banana skins/fruit contain phosphoric acid and potash

bindweed contains boron

blackberry contains iron

borage contains potassium

bracken fern has a high potassium content

broom contains magnesium and sulphur

chamomile contains calcium, potassium, sulphur

chickweed contains copper, boron , zinc, phosphorus, iron

citrus high in potash; oils and resins break down in compost, but better shredded

coffee grounds contain minerals, trace elements, vitamins, carbohydrates, sugars

comfrey contains phosphorus, calcium, iron, potassium, sodium. Invaluable in the compost,

helps get it 'started'

corn cobs weather in the open before shredding or grinding;  holds moisture well

dandelion contains silica, potassium (roots)

dolomite use in place of lime

feathers  good nitrogen content; need to be moist and may need lime/dolomite or extra plant

material to aid breakdown

fennel contains copper, potassium

fish high in nitrogen and phosphorus;  some may be oily.  Need plenty of soi l and moisture

for quick breakdown

grass high nitrogen content, helps create heat; spread carefully to avoid putrification

hair must be very wet; kept separately and rotted, makes a good insulating mulch

hops contain nitrogen and some phosphorus. High water content. Helps heat compost

horsetail high in si lica, calcium

gorse contains nitrogen

inkweed good source of potassium

leaves very high mineral content; shred leaves and mix with manure or nitrogen-rich material

for leaf compost

manure is a major traditional component of compost as it is high in nitrogen; any animal dung can be

used (except human, cat, or dog)

nettle (stinging) contains iron, phosphorus; it is a good compost starter

peas - waste from crops, high in nitrogen, good potash content

rockdust mineral rich

sawdust is best as mulch, needs supplementing with nitrogen, but helps aeration and moisture

retention (must be untreated)

seaweed - high nutrient value valying according to type; most are rich in potash and iodine.  Some must be soaked before use.  Can be composted dry or fresh.

straw - little nutrient value, but adds bulk; large quantities need nitogen supplement

tagasaste - high nitrogen content, breaks down quickly and can be coppiced as a compost crop.
Excellent too as mulch.

thistles contain nitrogen, copper, silicon

willow contains calcium

wood ash adds potash, some phosphorus.  Don't allow ash to stand in rain as water leaches

potash

wool waste decomposes when moist; contains nitrogen, potash, phosphoric acid

yarrow contains sulphur, potassium