I live in the Tampa area. If the nodules are starting near the soil line they're most likely roots. I've pulled my tomatoes from my aquaponics system and will start seeding over the next six weeks for November harvest. In the past I've grown producing plants, in my organic garden, into August only by spraying them with seaweed emulsion. It's simply too hot here to raise tomatoes, other than cherries, during our summer heat and humidity. ......Emmett