The Dormancy Clock

Where the year stands

Shortening days are half the signal that sends temperate plants into dormancy. Here is where the year stands at latitude 34.2°.

13h 55mOF DAYLIGHT
Days are still long
13h 55m
Daylight · shortening
Nights unknown

Temperature is the other half of the signal, and there is no forecast for this location. Check your own night temperatures before acting.

Days cross 12 hours in 60 days — September 28.

What this can and cannot tell you

Day length is one of two signals. Temperature is the other, and sources disagree about which dominates — Barry Rice writes that the relationship is not completely understood. Use this as a seasonal orientation, then check your night temperatures before acting.

Dormancy sets in when short days coincide with night temperatures of roughly 4060°F. A flytrap resumes making traps above 55°F, so a warm garage in January breaks dormancy early and exhausts the plant.

Where this is measured

No location set, so this is a default. Add a postcode on your profile and the clock becomes yours.

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