Growing Degree Days

Someone introduced this concept recently (boffer?).  I read the wiki on it was informed on things I'd never considered.  I never knew that there was such a measure based on temperature, but it certainly explains a great deal. Now I'm going to see if this information is available for the seeds I want to plant.  It should be a very good tool.

Thanks to whomever it was that introduced me to yet another interesting and important factor in gardening.

rabbithutch wrote:...Now I'm going to see if this information is available for the seeds I want to plant.  It should be a very good tool...

And that, my friend, is the hard part!

There's lots of info about what GDDs are and how they are used. But finding the data applicable to specific types of plants is very hard to come by.

I can tell you that, generally, tomatoes and corn need in the 1400-1700 GDD range.

Please keep us informed if you find specific data.

It's more likely you'll find info for specific pests rather than specific plants.

+1



All you ever wanted to know about Jubilee corn:

====MODEL INPUTS======
Model species/general links: sweet corn [Jubilee];
Type: crop
Model source/other links: Coop et al. (1993)
Calculation method: growing degree-days - corn
Lower threshold: 50 degrees Fahrenheit
Upper threshold: 86 degrees Fahrenheit
Directions for starting/BIOFIX: date of planting
Starting/BIOFIX date: 5 1
Ending date: 8 31
Model validation status: partly validated
Region of known use: Pacific Northwest

=====EVENTS TABLE=====
1. 104 DDs after planting: First emergence from soil
2. 308 DDs after planting: 5 leaf stage
3. 445 DDs after planting: 7 leaf stage
4. 883 DDs after planting: 5 inch tassels
5. 960 DDs after planting: 10 inch tassels
6. 1005 DDs after planting: 5% silk emergence
7. 1062 DDs after planting: 50% silk emergence
8. 1145 DDs after planting: 95% silk emergence
9. 1288 DDs after planting: 50% brown silks develop
10. 1412 DDs after planting: 95% brown silks develop
11. 1539 DDs after planting: Fresh market harvest
12. 1597 DDs after planting: Processing market harvest

rabbithutch wrote: ...Now I'm going to see if this information is available for the seeds I want to plant...

Good luck with that! Please share if you find any. I even wrote to several seed companies last year and got nothing. Some of them actually seemed to imply they do have the information but it wasn't something they were willing to share. Maybe if enough people expressed interest?

GDD This has some interesting info from MSU.

GDD calculator

http://adstest.climate.weather.com/outlook/agriculture/growing-degree-days

I don't know what part of the country this data came from, but you can see how much sooner they got their corn to market in 2009 compared to 2010/11.



I remember that I had fantastic weather in 2009 for gardening, and 2010 was the opposite extreme-a real dud, weather-wise.

This won't add much, but I hear that in parts of the northern US where the late June sun is up from 4 AM until 10 PM, the corn grows so fast you can actually hear it pushing skyward on a very quiet sunny day.

Since I live in the South, the only thing we could hear is the sound of a raccoon's teeth gnawing on the ears. 

Speaking of corn, the health-conscious, longevity seeking Blue Zones has a chapter on the Nicoya region of Costa Rica, where the source of protein is a combination of black beans and corn tortillas.  I think maybe the tortillas there have not been fried in advance, since they are made from scratch.

I surmise that eating fresh corn from the garden along with black beans (or pinto beans) and adding an organic avocado is a very healthy alternative to a steak, a nice juicy, medium-rare, boneless ribeye... I have to go to Whole Foods now.

Razed Bed wrote:Since I live in the South, the only thing we could hear is the sound of a raccoon's teeth gnawing on the ears.

 

I surmise that eating fresh corn from the garden along with black beans (or pinto beans) and adding an organic avocado is a very healthy alternative to a steak, a nice juicy, medium-rare, boneless ribeye... I have to go to Whole Foods now.

GDD can also be used in the IPM (integrated pest management) toolbox against garden pests.

There was an article in Urban Farm magazine (now defunct but still operate a website) on this subject.  I had never heard of it but saved the article.  It did state that it is difficult to find info on veggies (other than corn since farmers use it) and annual flowers.  I'm guessing that many of us could develop that for our locales based on observation of our own gardens.  Finding the GDD (growing degree days) wouldn't be too hard, and then using that info to correlate.  The author actually did this in her own garden for peas and has added info as she has been able to.  Sounds like a good winter time project!  Potentially develop for the different regions here on the forums.

I know a company like IntelliAir out of Archie, Missouri analyzes seed selection in terms of inputs like weather, soil moisture, degree days, planting dates, soil mapping, etc. for the farming industry...using both historical and live data.  They also do this for fruit and nut crops around the world.  I would imagine that there will be an explosion of information available like this for veggies in the future.

Could also become information overload.