Although some models don't count the hours below freezing... <http://davewilson.com/homegrown/gardencompass/…> I can see where bulbs might need to go by soil temperature, as opposed to air temperature. I found chill-unit maps of Iowa, Florida, South Africa, and New Zealand, but nothing worldwide. Keep on Googling. --Roy NW of Boston High of 9F here today. That could be lots of chill units, or none at all. ----- Original Message ---- From: Mark Mazer <markmazerandfm13@earthlink.net> To: Pacific Bulb Society <pbs@lists.ibiblio.org> Sent: Thursday, January 3, 2008 4:57:17 PM Subject: Re: [pbs] Asking for a hint of world map of chilling hours Please? A chill hour is 1 hour at 45F or below. > >Please could you tell us the units measured by the thermoclines on the map >of chilling hours - so many hours at how many degrees? It was impossible to >tell from the image. > >John Grimshaw