Re: HYB:Germination:Observations:Temperature and time

Note that I'm not trying to be argumentative, but as you noted the germination stops around the first week of April.  Might this also coincide with the night temperature not consitently getting down to 40 F or below?  Not being cold enough for proper cycling would cause the ones that prefer (or need genetically) to be cycled futher to stop.  This may also explain why some seeds germinate in the Fall as the temperatures drop.  They just needed a little more cycling not supplied by the previous April's weather. If you noted when the Fall germinants started it might give a clue as to whether the seeds germinated because of continued temperature cycling or day length.  If they germinated before the temperature dropped below 40 then it might very well be a daylength factor.


Paul Archer
Raleigh, NC  Zone 7

Original message:--------

>I'm not a scientist.  I simply observe in my own garden.   
>
>In the spring, I eagerly await the first sprouts in the iris seed  pots!  
>This can happen any time from the third week in February to the  first week of 
>April, depending on the season.  Spring temperatures trigger  the beginning of 
>the observable parts of outdoor iris seed  germination.    
> 
>A part of my spring routine is to note when the first sprout appears  
>(visible) on each cross!  In earlier years I also counted the seedlings  about once a 
>week and noted it in the workbooks.  Several years ago, I  determined that 
>the time span from first sprout to last sprout, of a given  cross, was 
>approximately a month.   This has held true without  regard to the time that sprouting 
>began for that cross.  
> 
>This one month span seems programmed into the iris seed, and may or may not  
>be connected to the bloom cycle.  Early bloomers sprout early and late  
>bloomers sprout late?  Anyone kept records??  Anyway, when a month has  elapsed the 
>seed shut down.  I suspect this is DNA triggered by time.   Is it day length?  
>I have no clue.  It's never been on my HAVE TO KNOW  list!  I just know it 
>happens.  
> 
>This month of time each spring is when I find it crucial to keep the pots  
>moist.  
> 
>My observation?  The iris seed has completed a cycle at this  point.  If left 
>outside, more seed may sprout the next spring but will  follow the same 
>cycle.  Sometimes a few seeds will sprout in the same  (first) fall.  (Or any 
>fall.) These do not require the same cycling as  the average seed.  The program 
>(DNA) is different for these seed.  
> 
>What is different??  What is missing, or present, in their  DNA compared to 
>the average iris seed?   
> 
> 
> 
> 
> 
> 
> 
>________________________________________________________
>Betty W.  in South-central KY Zone 6 ---If you don't cross them, you can't 
>plant them!  
>Bridge In Time Iris Garden@website:
>Where the seeds are in the pots once  again! 
>_www.thegardensite.com/irises/bridgeintime/_ 
>(http://www.thegardensite.com/irises/bridgeintime/) 
>_Reblooming Iris - Home Page_ (http://www.rebloomingiris.com/)  
>_iris-photos archives_ (http://www.hort.net/lists/iris-photos/)  
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>_AIS: American Iris Society website_ (http://www.irises.org/)   
>
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