I got a problem with my plants and i seem to be loosing them in record numbers. It's as if the tops of the plant are too heavy to be supported by the stems. They are relatively young (3-4) weeks, and i have had a few break right in the middle, the leaves seem to be fine up top but the stem is bent in half. The stem looks some what weak. Is there anything i can do to avoid this and or help the bent plants?