Although I've never ordered from them, I've checked out Rancho Gordo's site a number of times and they do have a great selection!
Sally, the "keep on bearing" comment forces me to report that when our main pole bean crop (Blue Peter, an heirloom bean that I've been growing since the mid 1980s for green beans) stopped flowering and we had picked pretty much all of the beans - around the end of August (the 25th, to be exact) - I gave them some triple-10 fertilizer, compost and bone meal, in the hopes that we would get a few more beans to eat (even though I already had plenty stashed in the freezer for the winter). It wasn't long until we started seeing more flowers developing, and in the past couple of weeks I think we have picked more beans than we did the first time around! For some reason it's never occurred to me to fertilize the beans partway through the season - lesson learned!
(next year I'll feed them sooner so we don't have that lull in production.)
