We asked biodiesel organisation 'Journey to Forever' how many sunflowers it would take to make a gallon of fuel to run a diesel car. We might as well have asked how long a piece of string is! It depends on what kind of seed you plant, some yield more than others, how it is grown blah blah! In the end we made an educated guess based on their information (thanks Keith).

160 organically grown sunflowers with adequate space would yield approximately a gallon of useable fuel. Linseed yields far more oil but doesn't make for a good block pattern!