Frost/Freeze page for Zip Code info - add chilling hours?

I greatly appreciate the addition of the calculator for displaying percentages for expected frost and freeze days for any Zip Code. It gives me more confidence in knowing when I can take the chance to plant new seedlings into the garden or begin to start frost and freeze protection efforts in the fall.

http://davesgarden.com/guides/freeze-frost-dates/

I'm wondering if there is some way to include a calculation for the number of expected chilling hours for a Zip Code on the frost/freeze page? In my particular situation -- with the borderline of Zone 8b/9a running almost precisely through my back yard in NE Florida -- the number of expected chilling hours is crucial in selecting cultivars of fruit trees that have the lowest chilling hour requirements.

By the way, I just added a new definition to DG Gardenology for "chilling requirements" based on what I could find on the Internet, which provides the following information:

If either definition could be used to calculate the number of chilling hours for any Zip Code, I think it would add some very useful information to the frost/freeze calculator page.

Thanks for all your diligent efforts in continuing to improve Dave's Garden with such wonderful features!

Jeremy

Jeremy,

This would be a valuable feature for me, too. Living in East Texas, we have exactly the same issues with selecting fruit trees.

Unfortunately, the data that I have does not include the length of time of chilling hours. In fact, it's not very granular at all. Without the data itself, I can't write the software to interpret the data.

Thanks, Dave, for considering my suggestion. If I can locate some compressed data for average chilling hours per Zip Code I will let you know. Maybe the National

For your own garden, you may be interested in this webpage from Texas A&M that I came across while searching for definitions of chilling hour requirements.

http://etweather.tamu.edu/chill.htm

I surfed around a bit and finally found this map for chill hours for Zones 8 - 10

http://www.sandybarnursery.com/chill-map.htm

I suppose all areas Zone 7 and lower would just be summarized as greater than 1200 chilling hours.

Also, the land grant/research university for food and agricultural science in each state may publish a map for their state. I came across this one for Florida from the U of Fla IFAS:

http://www.north-florida-garden-guide.com/fruits.html

Here's a summary of California counties chilling hours:
http://fruitsandnuts.ucdavis.edu/chillcalc/index1.htm#F

and I FINALLY found a map for the chilling hours for the entire U.S.! (compiled from research done by the University of Maryland).

http://www.raintreenursery.com/chill_hours.cfm

Perhaps you can get permission to use that map and post it somewhere in "Guides and Information?"

Jeremy

Jeremy,

This is interesting. That first link you gave shows the tracked information for Overton, TX which is just up the road from me!!! :) So at least I personally get precise data for my location. Now, if only this exact kind of webpage was setup for every region, we'd be in business here.

Dave

I will send a few emails to the National Weather Service and USDA and a few others to see if the raw data is out there for chilling hours for precise locations. From what I could ascertain by the sites I visited, there is lots of data available from about 8,000 sites around the country, but it looks like the only compilation of the data so far is the general map put together by the University of Maryland.

It will be an interesting project to see what we can pull together!

Jeremy