Q/A #138 - Venus Flytraps in San Diego

QUESTION:
I live in San Diego (USDA zone 10) and growing some Venus Flytraps. If my plants are in a greenhouse, is it still considered “Full Sun” (based on your pdf)? I also winterized my previous VFTs by keeping them in the fridge from December through February. Is this necessary? Or is it fine to leave them outside in a darker place during those months in my zone?
(Submitted in July 2020.)

RESPONSE BY JEFF DALLAS:
Your plants are getting full sun as long as your greenhouse is receiving direct sunlight without any obstruction and your plants are in the sunniest location in the greenhouse and not shaded by other plants. We have lots of plants in cold frames with poly covers and no shade cloth and they get plenty of sun. 

We also have lots of customers in the San Diego region. They've successfully overwintered their plants outdoors without the need to refrigerate them. Dormancy in the North American plants is brought on by the combination of temperatures and photoperiod. The photoperiod is the more important of the two. Your days get more than short enough to bring on dormancy, and it also gets cool enough for Venus flytraps to remain dormant. So just leave them outside (not in the greenhouse). 

Refrigerator dormancy is a last resort for folks in truly tropical areas near the equator. I don't even recommend it for folks in Hawaii since they do experience a mild seasonal change. Even there it's enough to trigger dormancy in most plants. Refrigerator dormancy is tricky, and losses tend to be high.

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