I germinated this batch of heirloom Tiny Tim tomatoes, and have been told that they start off really slow. It's been a month now. There are a couple of them that has a swollen stem like in the picture, and their growth seems to be stunted. I've never seen anything like this before, and it feels like all the nutrients the seedling absorbed are just sitting in that swollen stem. What's really happening here? And is there a fix for this?