Trench composting
An alternative method of recycling garden & kitchen organics
If you have the space, trench composting is a cool method which involves
less work but takes longer to mature, taking from six months to two years
depending on the nature of materials used, climate, and aeration conditions.
Compost made in this manner will still heat up at first, but not the
levels of hot composting. Although this means that it fails to kill most
pathogens and weed seeds, this is not a problem if you do not compost
diseased plant material or weeds that have gone to seed.
Getting started
Dig a trench 300-450mm wide to one spade depth (about 300mm) the length
of your garden row, mounding the excavated soil along the sides of the
trench. You may prefer to dig the trench as required. Place weeds, leaves,
twigs, lawn clippings, kitchen scraps, etc in the trench plus a little
manure if available, sprinkle garden lime on top and cover lightly with
topsoil. It is a good idea to have a supply of dry high carbon materials
on hand to layer in with lawn clippings and/or kitchen organics. Water
is usually not necessary unless materials are very dry. Continue this
process until row is finished then leave for about 12 months before planting
over.
To avoid unwelcome visitors do not bury meat, fish, or cooking/salad
oils as these may create odours.
Advantages
- One of the simplest forms of composting.
- Can rapidly improve poor soils, especially sandy ones.
- Allows you to add materials a little at a time.
- Can encourage earthworm activity.
Disadvantages
- Requires a relatively large garden area.
- Slow rate of decomposition due to tendency to form pockets
of anaerobic activity.
- Possibility of temporary nitrogen deficiency if planted over
too soon.
- To optimise this method, you need to balance carbon and nitrogen
as well as wet and dry materials as you go.
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