Hot composting requires more work, but with a few minutes a day and the right ingredients you can have finished compost in a few weeks depending on weather conditions.
The composting season coincides with the growing season. When conditions are favourable for plant growth, those same conditions work well for biological activity in the compost heap.
However, since compost generates heat, the process may continue later into the fall or winter. Hot heaps do best when high- carbon material and high-nitrogen material are mixed in a 1 to 1 ratio. A heap with the minimum dimensions of 1m x 1m x `1m is needed for efficient heating.
For best heating, make a heap that is 2 - 3 metres in each dimension. As thecomposition occurs, the heap will shrink. If you don't have this amount at one time, simply stockheap your materials until a sufficient quantity is available for proper mixing.
Hot heaps reach 110 to 160 degrees Fahrenheit, killing most weed seeds and plant diseases. Studies have shown that compost produced at these temperatures has less ability to suppress diseases in the soil since these temperatures may kill some of the beneficial bacteria necessary to suppress disease.
Steps for hot composting:
- Choose a level, well-drained site, preferably near your garden.
- There are numerous styles of compost bins available depending
on your needs. These may be as simple as a moveable bin formed
by wire mesh or a more substantial structure consisting of several compartments. There are many commercially available bins. While
a bin will help contain the heap, it is not absolutely necessary. You
can build your heap directly on the ground. To help with aeration,
you may want to place some woody material on the ground
where you will build your heap.
- To build your heap, either use alternating layers of high-carbon
and high-nitrogen material or mix the two together and then heap
into a heap. If you alternate layers, make each layer 2 to 4 inches
thick. Some gardeners find that mixing the two together is more
effective than layering. Use approximately equal amounts of
each. If you are low on high-nitrogen material, you can add a small
amount of commercial fertilizer containing nitrogen. Apply at a
rate of 1⁄2 cup of fertilizer for each 10-inch layer of material. Adding
a few shovels of soil will also help get the heap off to a good start;
soil adds commonly found decomposing organisms.
- Water periodically. The heap should be moist but not saturated.
If conditions are too wet, anaerobic micro organisms (those that can
live without oxygen) will continue the process. These are not as effective
or as desirable as the aerobic organisms. Bad odours are also more likely
if the heap is saturated.
- Make holes in the sides of the heap for aeration.
- The heap will heat up and then begin to cool. Start turning when
the heap’s internal temperature peaks at about 130 to 140 degrees
Fahrenheit. You can track this with a compost thermometer, or reach
into the heap to determine if it is uncomfortably hot to the touch.
- During the composting season, check your bin regularly to assure
optimum moisture and aeration are present in the material being
composted.
- Move materials from the centre to the outside and vice versa.
Turn every day or two and you should get compost in less than 4
weeks. Turning every other week will make compost in 1 to 3 months.
Finished compost will smell sweet and be cool and crumbly to the touch.