Re: Re: CULT: FERTILIZER: water and what-not

Well "turn off" is a generalization so be careful.  

Here is how I see it and welcome comments.

Nitrogen is used primarily toward foliage production and Phosphorus toward root and flower formation.  There can also be a balance/ratio between the two where both foliage and flower production can occur, So what is being "turned off" and/or "turned on"?... and why? ... or when?  The switch from foliage production to flower production might be considered a maturity level of a healthy fan that allows it to bloom or rebloom out of season.

The nitrogen must be also used at the right time.  If bud intiation has already occurred (generally after 8-12 weeks vernalization) and the nitrogen is applied (or still present from a previous application) in high enough quantities the stalk or buds will abort.  I'm sure this has been discussed  in this forum before and is mentioned in AIS Bulletins and other publications (search for Spring application of fertilzer).

The nitrogen may boost the side shoot formation and growth but the continued growth of mother fan will be lost as it does not return to vegetative growth.  If the mother fan had been spared those side shoots already present would grow as well as new ones would be formed as the fan continues to grow.


Paul Archer
Raleigh, NC  Zone 7



>Wow this must mean if I have an iris that tends to bloom out all I need is
>some 23-3-3 for a few years to get some increase. Then use the 23-3-3 on half
>and will not lose the iris to bloom out. Who would have thought that nitrogen
>would turn off blooms?
>
>
>Mike Greenfield

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