A couple of observations. First, never buy a 5" pot with 2 plants in it. No reputable nursery should even sell such a thing unless it was on some throw away table.

Second, I sure hope you separated those plants when planting them and if they didn't tell you to do that then that is another strike against them.

Third, I would think that the plants were probably already infected when you bought them (strike three) except that you mention it isn't on the oldest leaves. Is this on new growth since you got the plant or on leaves that were already there but just not showing symptoms?

Fourth, given all the fungus spores on the smaller leaves in the pic I would bet that yes the entire plant is already infected. If so then personally I would pull and dispose of it rather than going to all the work and expense of trying to save it with fungicides.

So yes, it appears to be gray leaf spot and well advanced IMO. If you want to try to save the other plants and they are not showing symptoms right now then begin an aggressive fungicide spraying program on them ASAP, preferably with Daconil.

This one I would pitch and personally I'd deal with another nursery in the future.

JMO

Dave

Thanks very much Dave.. I'm not an experienced vegetable gardener, so just trying to get some ideas and confirmation about my thoughts from reading limited info. I will pull that plant.. not worth keeping it. I agree that I think these were probably infected when i got them. I'm so silly that I actually saw some bad leaves on one of the Stupice plants, when I was putting it in the ground. I did separate the two plants from each container. Maybe I contaminated the other variety when planting. I still have three different varieties now, that so far don't show any infection and I will just hope for the best. I will read about Daconil and will find some if I decide to go to the trouble. Thanks very much for replying! R:)