I wait until mid- to late fall, when the pods have turned black and some have started to crack open.

I keep a close eye on them after the seed pods form. Once the pods turn black, I pop one open to see if the seeds are ripe. Here's what I wrote in my garden journal last year:

"Many fat seedpods formed by 6/12; harvested LOTS of seeds late July."

I'm guessing it's a lot warmer where you are and the pods might be ready quite a bit sooner. If you aren't sure, just harvest a few at a time, mark the date harvested and see how they do when you winter sow them. This is my second year to harvest & winter sow the seeds from my own plants and germination has been consistently 95% or better so I must be doing something right. Good luck and happy winter sowing!!!

Baptisias aren't hard to collect at least. They aren't like some plants where the pods pop open when they are ripe. The purple & the white ones are easy. I have Screamin Yellow, & pods on that one are almost like walnuts, thick & hard.

Thanks for the info. I appreciate it. I think these would look good along the back of my yard. I will plant seeds since the plants are expensive around here.

The seeds do well with winter sowing--I have 100% germination on the ones I WS back in December. They're very slow-growing however and do require patience on the gardener's part.