The closest thing I have to a secret is almost freezing them in the fall/winter. I keep them outside until the temperature falls into the 30s. Then they go into my little greenhouse and experience nights into the low 40s until January when the outside temps are in the teens and single digits. It is too hard and too expensive to keep my little greenhouse running. One year I will upgrade to something better than can function year round. For now this is the process. I keep them drier during the cold period, but it is not a hard dry rest.All nice. I have killed every attempt. What's the secret to your succes?