I recently dug up the avocado seed to discover it had cracked open and put a root down. I buried it again and instantly began to anticipate the day I would see green growth. I was very surprised to see green stuff the very next day - but it was coming from an odd area in the pot and has several shoots and I was perplexed. Later I found the same green growth in the Spearmint and then in the pot of beans.
The beans! Finally it clicked. This green stuff was not avocado, nor mint, nor bean. This was a new, different crop - one that I had NOT planted myself!
These things were coming from some kind of seed buried by that varmint chipmunk that has been skulking around these parts!!
It's funny because I see him (or one like him) running around on the ground with big mouthfuls of stuff. I guess some of those mouthfuls ended up in my pots. When I dug the green stuff up it revealed clusters of what look like small sunflower seeds. I think he gets them from the local bird feeders.
It's also funny to think of him coming back to his past burial sites for a snack only to find that plants have grown up from his stash.
Anyway, if I was a real farmer this would probably be troublesome and require pest-control but I quite enjoy my pests.
LATE EDIT:
The question is quickly becoming, "Where HASN'T that chipmunk buried seeds?!?" Several more deposits have sprouted overnight!!