Outdoor & Protected Cultivation
Latitude, Photoperiod & Seasonal Timing
Outdoor flowering behavior is shaped by genotype and changing day/night length, not a universal calendar date.
Key concepts
- Day length varies with latitude and date
- Plants respond to photoperiod through biological signaling rather than a simple clock date
- Cultivars can differ in the critical photoperiod that promotes flowering
- Seasonal temperature and frost risk interact with flowering duration
What to measure or observe
- Track local sunrise and sunset through the season
- Record first preflower and sustained floral development
- Compare cultivars grown in the same location
- Record local first-frost and heat history
Common mistakes
- Using another region's flowering calendar as a guarantee
- Treating all photoperiod cultivars as identical
- Ignoring artificial night lighting near the crop
Visuals this lesson still needs
- Latitude/day-length chart
- Seasonal flowering timeline
- Night-interruption concept diagram
- Cultivar-response comparison