The government-funded agency has worked with 36 councils in England and four in Scotland to supply households with individual compost bins.
This phase improves and expands on work done last year with 24 local authorities.
WRAP head of home composting Gary Hilder said: "The aim of this scheme is to build on the experience of phase one and to create a model that can measure the diversion of biodegradable waste from landfill. At the same time we also aim to recruit new home composters and support the activities of those already doing it."
The pilot projects will vary from council to council.
A small number have supplied bins for free, but in the majority of cases residents will be offered a home composting kit at a subsidised price.
The trial runs for the whole of 2005, after which its results will be evaluated and phase three launched in 2006.