Just for the record, I am also having problems with sweet pods recently (34.07).
I embark with 25 plump helmet seeds, 9 sweet pod seeds, 9 cave wheat seeds, 9 pig tail seeds, and 9 rock nuts. I checked the initial saves to see that I did in fact bring the sweet pod seeds, and I did.
I dedicate one field to each type, for all of the seasons during which they will grow. I don't begin cooking anything, let alone seeds, during the first year. I don't plant rock nuts in the first year since they can neither be brewed nor eaten raw, not do they produce clothing.
At the beginning of the second year, I have 9 cave wheat, 9 pig tails, and zero sweet pods. There are no sweet pod seeds, either, which is to be expected because I observed their planting.
The growth duration is the same for sweet pods as it is for cave wheat, but the seasons are different. Sweet pods grow during spring and summer, while cave wheat grows during summer and autumn. Perhaps the point made above about season lengths, in combination with the inevitably rushed timeframe during the first year when the plots are excavated and built, is the cause. If the sweet pod seeds were not planted until the end of summer, the sweet pods would not mature before their season ran out.
I probably did not see this happening before because previous to the relatively immediate demand for children's clothing I did not plant anything but plump helmets during the first year. Having decided to rush the first harvest of pig tails, I also decided to plant cave wheat and sweet pods in the first year. That is probably a mistake, at least for the sweet pods.