Most people haul dirt and plants, etc. in their trunk. Keep it clean by spreading a cheap shower curtain in the car trunk to catch spills and dirt. The shower curtain can be washed.
Amen to that suggestion! In fact, you should keep a folded plastic sheet of some type in the car trunk for garage sale finds, plants... at all times. I recently purchased a piece of exercise equipment that leaked greasy oil all over the seat. OMG!
No bargain there.