It's a fairly common idea and one that many if not most gardners use as long as the crops make. The problem I seem to have is I don't remember what all I've planted, much like many people don't know what's in their cabinets when thinking about what they want to eat. Today for instance it finally donged on me that I had chives in the garden. Probably not the worst thing to forget but I've had it there for almost two years now and this is probably only the second time I've used it.
The green onion up front has decided that it likes walking. For those of you who don't know what that is, it's when the flower stalk forms little onion plants in the flower head and bends over. The little onions then root and grow without going through the seed stage. Since I noticed them I was able to just remove them from the flower stalk and plant them in some of the pots that didn't have anything growing in them.
The large squash in the community garden is growing nicely. One of them is really getting big and two others are hanging in there. Hopefully this fall we'll have some nice squash to eat.