A one off investment in your soil which will continue to work for many years, 1kg will enrich 1sq.m. For trees or shrubs add 100g to the planting hole, or 5g per plant for vegetable and bedding plant transplants. About Grochar: A modern take on a 2000 year old tradition, GroChar was inspired by Amazonian Indians who used charred plant matter to enrich their poor, infertile soils. It is produced in the UK by a patented, clean technique which captures up to 70% of the carbon that would otherwise be released into the atmosphere by burning or decaying.