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Re: rooting temps

Shelly brings up a good point about rooting temps that I try and follow but
often forget to mention as it is part of the background activities in my
greenhouse.

DO NOT use cold water!  This is particularly important when dealing with
tropical species. This greatly disturbs the plant in general and cools the
rooting media down significantly.  It may take several hours (or longer)
for the temperature to return to the desired level depending upon your
heating source.

It is also desirable to wean the rooted cuttings from the warmer
temperatures prior to transplanting so the rate of cell division in the
roots is not suddenly stopped when the transplanted cutting needs to be
generating roots in order to establish itself in a new pot or site.  This
is why I prefer to root in small batches in flats or pots.  I have zones in
my propagation bed and can simply move the flats rather than having to
readjust the thermostats repeatedly.

When transplanting rooted cuttings it is equally important not to water
them with cold water.  I am on a well system and the water comes from the
tap a  42-43 deg F (6 deg C).

Molbak's, a huge commercial poinsettia grower near Seattle, installed water
heaters on their irrigation lines in the greenhouses after finding that
watering the plants with warm water greatly improved the quality of the
crop.  It cost a lot to install but they felt it was worth the investment.

I let the water to warm up in the greenhouse by letting it sit for a day or
so in a bucket or barrel.

To initiate another discussion, one also needs to consider lengthening the
photoperiod when rooting cuttings.  This is particularly important when
dealing with temperate woody species. Tropical equatorial species which
experience 12 - 14 hour photoperiods throughout the year tend to cease
growth when exposed to shorter light periods. This is very important for
those of us who live in the gray regions of the northern or southern
hemisphere.  But after reading the introduction of  Magnar Aspaker, who
lives 200 km north of the arctic circle, I'm less inclined to complain
about our short days.

I am curious about species that are often winter active.  Some of the
Helleborus (Christmas/Lenten Rose) or Cyclamen or some of the winter active
Aroids (Jack-n-the-Pulpit)  How does their root growth respond to long
photoperiods?  Anyone know of work published or have experience in this
area?

----------
> From: Shelley Dillard <rdillard@pobox.upenn.edu>
> To: seeds-list@eskimo.com
> Subject: Re: rooting temps
> Date: Thursday, January 09, 1997 5:07 AM
> 
> As as addition:
> This is important!
> I keep my bottom heat on 365 days of the year at at least 70 degrees F. 
For
> some particular species I turn it up or down.  The reason is that some
> cuttings will shut down if the temp goes down on a chilly night in spring
or
> fall.  They just will not start up again.  
> 
> Shelley Dillard


Best Regards,

Scott
..........................................................
Scott Gregory Vergara		
Washington     USA
USDA Zone 8 Ave Min Temp 10-20 deg F. Record low 0/hi 104 
svergara@pacific.telebyte.com,  HORTULANUS@aol.com
..........................................................
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