I wish I knew--I'm still fuzzy on what "moist but not soggy" means exactly. I did read online somewhere that you should water when the top 1-3 inches of soil is dry. A lot depends on your climate. Soil stays super moist here in western Washington, so I don't actually water mine much unless it gets really hot. But when I lived in the high desert of Boise, Idaho, you practically couldn't water enough, especially when the temps pushed 100. I tried growing a tomato there once and it died of thirst. =P My MIL always had great success there though. Hers were in the ground though, mine was in a container. Not sure how that all balances out.