Which bulking agents can be used in the HOTBIN?

What is the best (recommended) bulking agent?

There are several possible materials that can be used as bulking agents. However we recommended using partially composted dry wood chip.

What others are available?

The table below contains a list of other possible bulking agents and an assessment of their relative merits. Note: scored 1-5, 5 being highest and good, except on cost, where reversed 1 = high cost, undesirable)

For information on bulking agent to waste ratios view how much bulking agent is required?