Hi here is what I do with my tubes begonias. I plant them in 6 inch pots around the 15 of march I make a small ditch around the inner edge of the pot so that when I water it does not touch the bulbs other wise it could rot. I have done this for the last 3 years and it works out very good also they are under gro light the the light are on for 15 hours a day.Every year I grow about 30 of them. Anna Lisa