How do my indoor plants know when it's Spring?

[FloatyGimpy]

@lazybratsche

Yup, many (if not most) plants monitor the season primarily by the length of sunlight. Some flower after the day length increases above some threshold, others flower after the day length decreases below a threshold in the summer or fall. You can artificially manipulate this with sufficiently bright lights, and trick your plants into flowering at the wrong time of year.

Thank you! It’s very interesting!