|Better Farming Series 31. Biogas: What it is; How it is Made; How to Use it (FAO Better Farming Series, 1984)|
84. It may take up to three weeks or even a month for the waste in your biogas unit to start making gas. After that, gas will be made for about eight weeks.
85. During these eight weeks, half of the gas will be made in the first two or three weeks and the rest in the last five or six weeks.
86. If you find that not much gas is being made in the last weeks, empty the unit and start again.