ChloroFileNetherlands and the Low Countries
Photoperiods get 95 days between the daylight trigger and the killing freeze. 6,014 photoperiod varieties finish here, alongside 1,799 autoflowers.
Frost dates are De Bilt, Netherlands’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
- Southern Scandinavia81 days for a photoperiod
- Northeast Germany and Poland84 days for a photoperiod
- Eastern England85 days for a photoperiod
- Scotland and the north86 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.