GDD (Growing Degree Days)

PNW_D · July 1, 2006

One of my favourite topics :wink:

Here is a link that provides GDD for PNW:

http://pnwpest.org/cgi-bin/ddmodel.pl?spp=scn

Corn is the closest to tomatoes for comparison. I thought it was interesting how stages of corn growth can be compared to GDD, and starting thinking about how GDD relates to tomato growth (apart from ripening).

I have done some very basic record keeping in the past related to ripening, but perhaps will start making notes on tomato set as well.

Weather here has been unbelievable, and I have tomato set on many of my plants; Orange-1 and Purple Russian are amazing so far!!

And, for those that are interested, GDD as suggested in Territorial's 2002 catalog:

Ultra-Early: 1100 heat units (=GDD)
Extra-Early: about 1300 heat units
Early: up to 1500 heat units

Tania · July 4, 2006

D., thanks again for the link - I am now sold on the GDD thing, and am doing record keeping this year too.

Re the weather in Vancouver - it is quite unusual indeed! No rain since mid-June, and it is hot! I am tired of watering, both the garden and the containers, too much watering work for me after work... I soaked the tomato beds really deeply on Friday, and today the soil was dry within the top 1'. Had to water again.

However, the tomatoes and cukes love the weather - I picked 6 ripe New Yorkers and a few Bloody Butcher, Fruhe Liebe, and TUmblers today, and some cukes. Yummmmm... the salad was so good.

To great summer in PNW!

habitat_gardener · January 1, 2010

If only I could juggle numbers to improve my tomato garden!

I've been thinking about what proportion of early vs. other tomatoes to grow, since my garden site is fairly cool. Looking at GDD for my area, assuming I plant on April 1, by the end of June the cumulative average GDD is 981, then 1494 to July 31, and 2009 by Aug 31 and 2472 by Sept 30. How can that help me choose tomato varieties?

I also plant a couple transplants as early as March 1, with walls-o-water or (as they get bigger) bubblewrapped cages. The plants stay toasty inside, and I've had a few ripe tomatoes as early as the beginning of June, but no regular production until July. Because we've gotten freezing temperatures as late as mid-April, and cool nights through May or later, the cages stay wrapped at least a little until the end of May. I'm wondering if more protection might help boost production of some later varieties.

Most years the season ends with a freeze the first week of December. Usually, all but cherry tomatoes have stopped producing by mid-October, though in different years I've picked Cherokee Purple, Druzba, ARGG, or Bonny Best into November. In 2009, most varieties except cherries were done by mid-Sept.

July 1, 2006	#1
PNW_D Tomatovillian™ Join Date: Jan 2006 Location: West Coast, Canada Posts: 961	GDD (Growing Degree Days) One of my favourite topics :wink: Here is a link that provides GDD for PNW: http://pnwpest.org/cgi-bin/ddmodel.pl?spp=scn Corn is the closest to tomatoes for comparison. I thought it was interesting how stages of corn growth can be compared to GDD, and starting thinking about how GDD relates to tomato growth (apart from ripening). I have done some very basic record keeping in the past related to ripening, but perhaps will start making notes on tomato set as well. Weather here has been unbelievable, and I have tomato set on many of my plants; Orange-1 and Purple Russian are amazing so far!! And, for those that are interested, GDD as suggested in Territorial's 2002 catalog: Ultra-Early: 1100 heat units (=GDD) Extra-Early: about 1300 heat units Early: up to 1500 heat units __________________ D.

July 4, 2006	#2
Tania Tomatovillian™ Join Date: Jan 2006 Location: Anmore, BC, Canada Posts: 3,970	D., thanks again for the link - I am now sold on the GDD thing, and am doing record keeping this year too. Re the weather in Vancouver - it is quite unusual indeed! No rain since mid-June, and it is hot! I am tired of watering, both the garden and the containers, too much watering work for me after work... I soaked the tomato beds really deeply on Friday, and today the soil was dry within the top 1'. Had to water again. However, the tomatoes and cukes love the weather - I picked 6 ripe New Yorkers and a few Bloody Butcher, Fruhe Liebe, and TUmblers today, and some cukes. Yummmmm... the salad was so good. To great summer in PNW! __________________ Tatiana's TOMATObase

January 1, 2010	#3
habitat_gardener Tomatovillian™ Join Date: Apr 2008 Location: California Central Valley Posts: 2,543	If only I could juggle numbers to improve my tomato garden! I've been thinking about what proportion of early vs. other tomatoes to grow, since my garden site is fairly cool. Looking at GDD for my area, assuming I plant on April 1, by the end of June the cumulative average GDD is 981, then 1494 to July 31, and 2009 by Aug 31 and 2472 by Sept 30. How can that help me choose tomato varieties? I also plant a couple transplants as early as March 1, with walls-o-water or (as they get bigger) bubblewrapped cages. The plants stay toasty inside, and I've had a few ripe tomatoes as early as the beginning of June, but no regular production until July. Because we've gotten freezing temperatures as late as mid-April, and cool nights through May or later, the cages stay wrapped at least a little until the end of May. I'm wondering if more protection might help boost production of some later varieties. Most years the season ends with a freeze the first week of December. Usually, all but cherry tomatoes have stopped producing by mid-October, though in different years I've picked Cherokee Purple, Druzba, ARGG, or Bonny Best into November. In 2009, most varieties except cherries were done by mid-Sept.