What is hot composting?• A batch process: mix it all at once from material you have collected• It is free• Unlike other methods of composting it kills weed seeds and pathogens• Can deal with meat, dairy, onion and citrus scraps
Scientific definition• “An aerobic process of• fast oxidation which• breaks raw organic materials into• humus• at temperatures of up to 60°C• within three weeks”
What goes in it?Green and brownGrass clippings leavesCoffee grounds strawManure sawdustKitchen scraps shredded paperGarden waste Tissues, cardboard rolls
Why hot compost?• Improves soil structure and adds nutrients• It is quick. Finished compost in a few weeks• Higher nutrient content due to less leaching of nutrients• Greater volume than cold compost• Fewer viable weeds and weed seeds (keep out couch and kikuyu)
Dealing with perennial weeds• Weeds like couch and kikuyu can be either solarised or drowned.Either• put them into heavy black plastic bags and leave in the sun for several months.Or• put them in a bin and cover completely with water for several months.The resulting contents can then be composted.
How to make hot compost• One third green• Two thirds brown• 3 bin system• Layer the materials and water each layer well• Every so often add comfrey leaves or yarrow• When finished cover the top with damp newspaper and cover with lid
• After 4 days turn into next bin• After 2 weeks build another pile• Then regularly turn each of the piles into the adjacent bins• You will have a regular supply of compost depending on how long your materials last and how diligent you are at collecting
Tips and tricks• Watch out for people giving away compostable materials e.g. horse manure, coffee grounds, chicken manure• Collect leaves from the sides of roads• Ask people for their lawn clippings• Get shredded paper from the office if you can• Dampen newspaper and tear into strips
• Ask juice bar owners if you can have the pulp from juicers if you are there at cleanup time• Compost mates: collect food waste from local cafes and compost it in home or community spaces
Why comfrey is your best friend• Comfrey is a dynamic accumulator - it sends down a series of deep taproots and extracts and accumulates large quantities of potassium (around 7%) and phosphorous (around 1%), calcium (around 3%), magnesium and other trace elements from the depths.
• These nutrients are stored in the leaves, which can then be used to feed other plants.• Comfrey is in effect mining nutrients out of the soil, because of the deep taproots which reach deeper than normal roots can go
Make it easy• make do with whatever you have around• optimal shape for a compost heap is approximately 1m wide and 1m high and at least 1m long• Build the heap in thin layers of different materials approximately 5cm thick and water each layer before progressing to the next.
• When the heap finally starts to cool down (around 2 – 4 weeks) worms will come in• Finished compost should be dark, fine and spongy with a pleasant earthy smell. You should not be able to recognise any of the original ingredients in it
2 main possible problems• It stinks: turn and add brown material – carbon e.g. shredded newspaper• Nothing’s happening: turn and water well. Maybe add some manure or grass clippings, blood and bone or comfrey.The more effort you put in, the quicker you will get compost
How to useLike any other compost• Compost tea• As a mulch• Dug into top layer of soil