About 20 people learned how to make compost with tutors Diana Davis and Halina Horn, and biochar with Dylan Graves at the community garden.
Ms Davis said the aim of composting was to feed the soil and improve its structure. "You’re looking for a mix of nitrogen-type green material and brown material like leaves and twigs, which are rich in carbon."
While it was not always practical to build a compost heap in one sitting, there were advantages in saving the material and doing that.
"The best way to get a hot pile is build it all at once." Sometimes she turned the compost heap and put a layer of freshly cut lawn clippings in to speed up the process.
It was good for the compost heap to sit on the ground so worms could find their way into it.
Ms Horn said in nature there was very little that could be called waste.
"Everything has a purpose and composting is a very really good example of that."
Composting was "mimicking a natural process" and " turned waste into gold".
Mr Graves said biochar was made in a similar way to charcoal except after the burning process only the char or carbon was left in the remains.
Usually waste products including small branches and corn cobs were burned to produce biochar.
"By the management of how we burn it, we exclude the oxygen from coming into contact with the carbon."
Branches were placed strategically on top of the fire so the flames provided a barrier to stop oxygen becoming part of the burning process.
"The stuff underneath’s still getting hot, it’s still off-gassing and you are burning all those gases."
It was good to add biochar to the garden after it had been soaked in a nutrient-rich solution because it would then release goodness into the soil.