a person who has car parts spread out on their front lawn. The parts are usually old and rusting - they've been there for a while.
Car parts scattered across the yard, as if seeding the small parts to grow into a full automobile.
car parts = seeds
front lawn = earth, soil, etc.
having car parts laying around on your front lawn = *see also "white-trash"
"My neighbor has tons of old rusty car parts sitting on his front lawn... he's such a car-farmer!"
"His car-farming is brining down the property value!"
Someone who has multiple cars in their backyard, lawn, or field, most of which dont work, but they keep them because they are "going to fix them up", or are "selling their parts". Usually a car farmer will continue buying cars and even justify the buying of a new car with the sale or fixing of one of their old ones.
That guy has bought his eighth car, and even though he says that he is fixing his other ones up, you know hes not. He is such a car farmer.