I was having trouble getting germination until I restarted the germination pad. For awhile I was leaving a small amount of water in the bottom of the tray but decided that was not a the best idea. Now I just check the cubes for weight every day and pour a little nutrient solution around them if they seem light. Capillary action does the work.
These tomatoes are supposed to be able to set fruit at 40F. The source is Reimer's Seeds, which has a number of cold-tolerant tomato varieties.