With so many valuable comments in the DB I sometimes get frustrated not knowing the commenter's growing conditions. What do you think about the value of including the posters location and hardiness zone along with their user name?

Yes, knowing the growing conditions in which the poster grows his/her plant, location and hardiness is very valued info!

I really value the comments section, and I especially like the last half of your suggestion. Since you can click on the user name to quickly get to to a profile where many have already listed their locations and zones, would that be too redundant? I don't necessarily think so. Some people would rather not post their location (city/state) for various reasons and I get that. I don't always choose to state my location in places where I post on the Internet either. TMI.

While you can also find the zones in the profiles--if users have elected to put them there--it would be nice to have the zone info right with the comment as well so people could fill it in at that point if they so choose. There are a couple of scenarios I can think of that would make that very useful indeed, such as where the location of the poster and the location of the plant they are commenting about are different zones. That's stated a bit clumsily, but hopefully you get the point. Or in cases where it's a general informative comment about the plant and isn't zone-specific, that spot could just be left blank.

Is that do-able? I have no clue.

This is do-able. Let me contemplate it a bit.