[tomato] Re:Tomato Fruit Set & Cold Weather

Poris@aol.com (Tomato@GlobalGarden.com)
Thu, 22 Apr 1999 11:34:45 EDT

Bill wrote:

It is my understanding that tomato flowers will not set fruit if the 
temperature drops below @ 50 degrees F.  Have several questions.  
First, is this accurate?  Second, if yes, is there a minimum period of 
time they need to below 50 before the blossoms are damaged, or is it 
if it occurs for any period of time.  Finally, does all this apply to 
Stupice tomatoes which supposedly do well in cool weather.

   I live in the Santa Cruz Mountains of N. CA USA.  My night temperatures go 
down into the lower 40's (F) in April and May and into the upper 40's (F) 
through the beginning of June.  I start my early tomatoes indoors in February 
and plant them outdoors at the beginning of April.  Two weeks later, I start 
the rest of my species.  I am getting better at growing seedlings and believe 
that 6 weeks after sprouting is the optimum time to transplant.  My daytime 
temps can be as high as 80F as early as April and May.  I have gotten 
tomatoes as early as the end of April (20 miles from here, within 200 yards 
of the Pacific Ocean) with just the use of wall of waters outdoors (maybe a 
5F improvement?).  Most years, I get tomatoes by Memorial Day.  Maybe the 
fraction of time spent above the critical low temperature during daylight 
hours (whatever it may be) is an important variable.  Most years I also have 
a low chance of rain during the first part of my growing season, but often 
have night fog.  I do have better luck with certain species.  Kotlas and 
Stupice are my standard early tomatoes.  I have been experimenting with 
Sasha's Altai and Galena.  Last year was a disaster due to El Nino and I did 
not learn much about these species.  Most of the cherry tomatoes will also 
set fruit early for me as well (sweet 100 variations, red currant, golden 
pearl and Sun Gold).  I guess genetics is the predominant factor on how early 
the plant will flower, but it seems that for my situation, if it flowers, it 
sets fruit.  Oh yeah, I plant all  my tomatoes in 3 inch deep perlite 
hydroponic beds and feed it a standard hydroponic nutrient formulation.

Jaime (in the Santa Cruz Mountains of N. CA USA)