Composting Garden Waste

Tuesday, 4 February 2014  |  HOTBIN Composting

Most things from a domestic garden can be composted with a little care and time. You can speed up the process by shredding or chopping thick, woody stems, as this helps the bacteria to reach the soft digestible cellulose behind the protective bark. The length of time depends on the size of the pieces and whether the wood pulp has be de-lignified in the pulping process.

Garden Waste Will It Decay Cold Hot HOTBIN decay rate Comments

Accelerator Powders

Yes Yes Yes Fast Questionable value
Alfalfa Yes Yes Yes Medium  

Autumn Leaves

Yes Yes Yes Slow Can be hard to break down - we recommend adding dried and roughly shredded autumn leaves in small handfuls each week.
Bird Feathers Yes Yes Yes Slow  
Bone Meal/ Blood Meal Yes Yes Yes Fast These can help speed up composting.
Branches Yes Yes Yes Very slow The larger the branches, the slower they are to compost. You really should shred or chip.

Coir - Coconut Husk Fibre

Yes Yes Yes Very slow Takes a long time, but the fibres do mix in.
Conkers Yes Yes Yes Very Slow Protective shell will take longer to compost. Chopping or smashing them up will help to compost more efficiently.
Couch Grass Yes Not Advised Yes Medium Should only be added once the HOTBIN has reached 60°c to ensure that all of it is composted effectively.

 

Diseased Plants Yes Not Advised Yes Medium High temperatures kill disease virus/bacteria.
Deep Rooted Weeds -  Dandelion, Ground Elder Etc Yes Not Advised Yes Medium  
Fertiliser - Ammonium Sulphate No Yes Yes Fast Limited value & high cost.
Flowers - Stems, Dead Heads, Roots Yes Yes Yes Medium  
Shell of Garden Snails Yes Yes Yes Very slow Speed up composting by crushing the shells - please check they are empty first!
Grass Yes Yes Yes Medium Grass is a large volume waste. It can be tricky to compost quickly in a cold compost bin. We recommend drying the grass out slightly to prevent excess water from entering the HOTBIN.
Grass Sods Yes/No Yes No Medium Adding these will only block airflow through the HOTBIN. Only the grass composts.
Grass With Weed Killer On It Yes Yes Yes Medium Domestic weed killers are biodegradable - please check individual product instructions.
Green Leaves Yes Yes Yes Medium Shred waxy leaves.
Ground Cover - Nettles Yes Yes Yes Medium  
Hay Yes Yes Yes Medium  
Herbicides Yes Not Advised Yes Medium Domestic herbicides are biodegradable - please check individual product instructions.

 

Hydrogels - SAP, PAM Yes Not Advised Yes Slow Can also be added to soil.
Japanese Knotweed Yes Not Advised Not Advised Medium The verdict is still out on hot composting this.
Leylandii Conifer Yes Yes Yes Slow Ensure these are well shredded or chopped and add in small amounts rather than a single layer.
Lime - Calcium Carbonate No Not Advised Not Advised - Lime is not biodegradable. It alsoaffects the ph levels and can stop the composting action so is best left out.

 

Moss Yes Yes Yes Slow Takes ages - it is best added in small amounts each week.
Old Compost Yes Yes Yes Slow Acts as a fantastic kick starter!

Other Non-Native Weeds

Yes Not Advised Yes Medium  
Peat Yes Yes Yes Medium  
Perlite No Not Advised Not Advised - You can add this to your soil.
Pesticides Yes Not Advised Yes Medium Domestic pesticides are biodegradable - please check individual product instructions.
Pine cones and pine needles Yes Yes Yes Slow  
Plants With Fungus On Yes Not Advised Yes Medium High temperatures should kill the fungi.
Prunings Yes Yes Yes Slow Shred or chop where possible.
Biodynamic Powders - Humofix, QR Yes Yes Yes Fast Not needed but can be added.
Ragwort Yes Not Advised Yes Medium Should only be added once the HOTBIN has reached 60°c.
Rock /Volcanic Dust No Not Advised Not Advised - We question the reason for adding small rock particles to compost.
Rhubarb Stems & Leaves Yes Yes Yes Medium  
Seaweed Yes Yes Yes Medium Ensure the salt is rinsed off. Seaweed is thought to encourage other materials to break down more quickly.
Soil No Not Advised Not Advised - It seems counter-intuitive not to add soil however, try not to! Large sods and/or thick layers prevent aeration and could cause your HOTBIN to become anaerobic. You only need to use a small handful to inoculate a new heap.
Slugs & Snails Yes Yes Yes Medium (shells - slow) Kinder to add once dead - the high temperatures would kill them.
Straw Yes Yes Yes Medium  
Twigs & Brambles Yes Yes Yes Slow  
Vermiculite No Yes Yes - Can add to soil.
Weeds - Convolvulus, Dandelion, Bindweed, Buttercup & Horse Tail Yes Not Advised Yes Medium Safer to compost in a hot composting bin - as the seeds are likely to survive cold composting.
Waxy Leaves - Ivy, Laurel, Holly Yes Yes Yes Slow Shred or chop these before adding. Do not add in thick layer and mix in well.
Worms Yes Yes Yes -  
Zeolite - White Cat Litter No Not Advised Not Advised - Can add to soil.