ChloroFileSouthern Scandinavia
Photoperiods get 81 days between the daylight trigger and the killing freeze. 3,436 photoperiod varieties finish here, alongside 1,799 autoflowers.
Frost dates are Stockholm, Sweden’s: the median last spring and first autumn freeze across 1991 to 2020, from that station’s daily records, held by NOAA. Your own plot will differ by a week either way.
Showing 60 of them, split between the two flowering types and capped at three per breeder so a single large catalogue cannot fill the list.
Frost dates are 50%-probability averages. A sheltered, south-facing spot buys you a week or two; a low frost pocket costs you the same. Treat the margin as a planning number, not a guarantee.
Somewhere else
Every region the frost data covers, nearest continent first.
Europe
- Northeast Germany and Poland84 days for a photoperiod
- Eastern England85 days for a photoperiod
- Scotland and the north86 days for a photoperiod
- Netherlands and the Low Countries95 days for a photoperiod
- Bavaria and the Alpine foreland95 days for a photoperiod
- Cornwall and the southwest115 days for a photoperiod
- Southwest France120 days for a photoperiod
North America
- Canadian Prairies29 days for a photoperiod
- Saskatchewan32 days for a photoperiod
- Northern Minnesota39 days for a photoperiod
- Duluth and the Lake Superior shore58 days for a photoperiod
- Inland Pacific Northwest67 days for a photoperiod
- Wisconsin and the Great Lakes73 days for a photoperiod
- Colorado Front Range75 days for a photoperiod
- Upper Midwest77 days for a photoperiod
- US Northeast, inland79 days for a photoperiod
- Snake River Plain81 days for a photoperiod
- Eastern Great Lakes88 days for a photoperiod
- British Columbia coast90 days for a photoperiod
- Ohio Valley93 days for a photoperiod
- US Mid-Atlantic111 days for a photoperiod
- The Carolinas114 days for a photoperiod
- Pacific Northwest coast115 days for a photoperiod
- Southwest high desert116 days for a photoperiod
- New York City area117 days for a photoperiod
- California Central Valley137 days for a photoperiod
- US Southeast141 days for a photoperiod
- North Texas146 days for a photoperiod
Oceania
- Central Otago high country66 days for a photoperiod
- Southland90 days for a photoperiod
- Tasmania, Derwent Valley107 days for a photoperiod
- West Coast, South Island110 days for a photoperiod
- Kapiti and the lower North Island115 days for a photoperiod
- Victoria goldfields116 days for a photoperiod
- NSW Central Tablelands123 days for a photoperiod
- Northern Victoria135 days for a photoperiod
- South Australia, Limestone Coast137 days for a photoperiod
- Western Australia wheatbelt150 days for a photoperiod
Asia
- Northern China104 days for a photoperiod
South America
- Argentine Pampas143 days for a photoperiod
Track one of these
ChloroFile carries this whole reference offline. Pick a variety when you add a plant and it fills in the type, seed type, and flowering window, then logs what actually happened against it.