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Re: Heating cables

> > > Any advice from seasoned growers on how to supply warmth for
> germination?
> > > What are the pros and cons of each kind, such as heating cables
> versus other
> > > practices, etc.
> >
> > For just a few trays worth, you can use a "baseboard" type heater
> set on low.
> > By baseboard type I mean one of those long heaters which doesn't
> have a
> > glowing element in it, making it relatively safe to use this way
> (I've done
> > it myself many times).  Set some narrow boards up on cider blocks,
> so that
> > there is enough room for the heater plus 3-4" headroom underneath.
> Set up
> > your florescent lights (or whatever) over this.  If you can enclose
> this
> > somewhat to retain the gentle heat (you're aiming for 25-30°C) all
> the better.
> >
> > If you want to do more than this than I'd reccomend getting a soil
> heating
> > cable.  Some of the shorter ones come with a thermostat built in,
> but you
> > cannot adjust preset temperature range they go on/off at.  I prefer
> cables
> > without the built in thermostat and use an external, adjustable unit
> to
> > control the heat.  These cables come in various lengths, up to 240'
> long.
> > The 100' long cable is enough to cover the equivelant of a 4x8 area
> (a full
> > sheet of plywood).  I have a bench with 1" built up sides, filled
> with clean
> > sand that the heating cable is sunk into.  It works great and allows
> me to
> > get good germination of warmth requiring seeds without having to
> overheat
> > my entire greenhouse.
> >
> > I'm sure there are other simple methods that have been successful
> for growers.
> >
> > > Also, at what point is it beneficial to reduce the heat for
> seedlings to
> > > prevent  leggy growth?
> > As soon as the bulk have germinated remove the seedlings from the
> heat.
> > "Growing on" temperatures are typically 10-15°C lower than those
> required for
> >

   Once the seeds have germinated, they don't need heat as much as they
do light - leggy seedlings happen from too little light, not heat.
another method of supplying heat to seeds is to plance the trays over
the flourescent fixtures.   although my fixtures are always set for a
specified # of hrs. per day, this does not seem to affect germination.
I also will often enclose seeds in small plastic bags - they can even be
placed on top of the refrigerator.
by the way, I always enclose seed trays in  large plastic bags to keep
them moist.
any kind of heat cable is good - I do the cable in sand for cutting
propagation, but I also have one buried 3" below soil in a cold frame
(or very short hoop house -if you will)- this is great for when my
growing area in the house has exhausted it's size limitations - I put my
most mature genera of  perennial seedlings in this tent, wean them from
the heat, get them into an unheated frame, wean them from any shelter
(this is called hardening-off) and then they're on their own.  I can get
them out sometimes as early as mid March this way - they are perennials,
and if they can't stand a little cold, why are they called perennials?
hope this helps
Rika   http://www.willowpondnursery.com
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