Dam...yup, thats much to early. That would spell trouble for the rest of the grow for sure. Sorry to hear bout that! The indoor grow I ran this summer of mixed crosses, well I ran them indoors just as a test run but I added a shit ton of stress to those girls....I ran the room hot, kept them in small containers, starved them for water and played with the lights ETC...just tortured those poor things. I started stressing them early, when they were leaving seedling stage and going into veg and continued with the stress into three weeks of flower. I wanted to see if they would hermie early during pre plower and show balls and pistils but intrestingly enough they sexed out as true females and true males. Even after all that punishment I put them through, the few that threw out nannas didnt do it until very late into flowering with one to two weeks left before finish.
Its easy to miss a girl with nannas...sometimes they are buried kinda deep in there and can be difficult to spot. I had one plant slip undetected. I didnt see the nannas until just recently when I was trimming her up with a final trim. She had already been curing for close to 60 days and I had already given her a once over. So ya...sometimes those nannas hide themselves pretty good. She had to of thrown those nannas out late as well as the reast of the grow was unaffected.
Another thing to note is that I have bought ceeds from some of the most credible breeders and seen thier ceeds do the same thing into late flowering. It really is not that uncommon for plants to do that and what I have found is that there are so many things that can stress a strain/plant and she will react to it by expressing nannas. Sometimes I cant even pinpoint it to anything specific because my grow rooms are designed for optimum grow conditions and I still see this occurance from time to time and yet I can take the same ceeds and grow them outdoors and not see a single problem/nanna from start to finish. Soooo, IMO when I see that, I clear the ceed as a success. In my experience, Ceeds that are genetically prone to hermie tendancies will hermie regardless if they are grown indoors or outdoors....nothing you do or dont do will stop them from doing it.....plain and simple they are going to hermie no matter what!
Breeding is allot of work. Allot more work then just growing bud. I do most of my breeding outdoors and when I do it I have already selected the strains that are going to recieve pollen and from which male as to confine that grouping to one area and if its a breeding season for me then I have multiple groupings spread out over miles of terrain to avoid wind driven cross pollination. The result is a grip of bud for personal use with a grip of ceeds for the same, personal use. Sometimes I collect pollen and save it and maybe brush a little on a indoor girl...just a branch. I pollenated one flower only and it produced over 100 viable ceeds....so you can imagine what two full plants fully pollenated will produce in ceed numbers....thats right...thousands!!!!! Another thing that really helps out with breeding projects is to use the most stable genetics you can get your hands on....if you start with stable strains, you usually end up with stable F1 hybreed crosses. Now when you start backcrossing and cubing for selected phenotypes and genotypes while trying to keep the strain your working on homozygous ( true breeding ) that gets quite involved and takes ,in some cases several years, allot more work.