John,
not in a quality that will work. My job is LED developement. Cheap
LEDs bring nothing but disappointment.
cheers,
J.
Am 06.12.2015 um 18:20 schrieb John
Ralph Carpenter r*@googlemail.com [iris-species]:
LED growlights in the red/ blue spectrum are available for around
£5.
On Sunday, 6 December 2015, Jamie j*@freenet.de
[iris-species] <i*@yahoogroups.com>
wrote:
>
>
> Mornin', Walter et all,
> with my experiments, it was not simply Iris, aril or
otherwise, but many different genera. The key problem is the
higher temps combined with insufficient light. This leads to
faster growth after germination which cannot be properly supported
by the possible photosynthesis. Yes, one could simply increase
the light amount, but this is a very costly road, especially in
Europe where our charges are about 3-10x what one pays in the USA,
and, I have not found the end result warranted the extra effort
and cost. In short, those seedlings I raised in a cold-house or
cold frame managed to quickly catch-up to those under lights and
finally, as far as I could observe, produced superior seedlings.
My extra efforts were wasted.
>
> In a light laboratory, one does manage to obtail better
seedlings, again, higher costs, but part of the reason is the
actual spectrum of light used. A basic misconception is that what
appears as strong light to the human eye is strong for the
plants. As most will recall, photosynthesis for land plants is
taking place mainly at 660nm (plus 720nm with some plants) and
420nm and 470nm. This is essentially very red and very blue
light. Actually at the edge of our ability to register light as
visible. Clearly, there are light sources designed for plants,
which respect these needs, but many do not really offer the plants
the best radiation, rather attempt to appease the human eye and
are emmiting lots of (useless) light in the yellow-green part of
the spectrum, which, not coincidentally, is the peak of the human
light experience. The colour of our sun! In the end, we only
have our eyes to judge lighting, unless we use a spectrometer.
>
> To give you all a better idea of the light involved, I have
attached a graph of chlorophyll light absorbtion. There are other
light-gathering pigments involved in certain plants, but for our
purposes, chlorophyll and caroteinoids are the main pigments
involved.
>
> Another factor many do not know about is the life-span of
fluorescent light sources. After about 6 months they start to
strongly move to the yellow spectrum. After 9 months they are
pretty much useless for plants. Sodium is an option, but has a
similar deficiency and is less efficient at producing light, watt
for watt. The best light source would be top-line LEDs in the
proper spectrum. Again, we come to an economic factor, which is
why I have decided the natural light/coldframe approach was the
winner.
>
> One area I do find interesting for under light culture is
giving forced arils a good start. Here, lower temps are pretty
important, as none of them do much growing under high heat. Room
temps are to high, IMO. On a cold windowsill with supplemental
lighting, I have brought them to an intermediate size (second leaf
or so) and then transfered them outside to a cold frame.
>
> ciao für now,
>
> Jamie V.
> Cologne
>
> Am 04.12.2015 um 21:48 schrieb Walter Pickett w*@yahoo.com
[iris-species]:
>
> So Jamie says he has poor results growing new arilbred
seedlings over winter under lights, and Dennis says he has had
good results doing the same thing with LA iris seedling.
> I respect both based on what they have said over the years on
the internet. They both seem to know what they are doing. But I
wonder if the different results are due to the species they have
worked with, or on the amount of light or other conditions in
their light set-up.
> Please keep us informed of results, and if possible, describe
the conditions you are growing these seedlings in.
> Walter
>
>
> On Monday, November 30, 2015 2:07 AM, "Jamie j*@freenet.de
[iris-species]" <i*@yahoogroups.com>
wrote:
>
>
>
> Dennis,
> nice! Have you considered potting them up and over-wintering
them in a coldframe? I have found seedlings do very poorly inside
during Winter. They attenuate and often become quite weak by
Spring. In a coldframe they growm more slowly, but we see a
better root system and compacter growth. Also, roots continue to
develope and grow when temps are above 4°C, while the leaves
develope little, if at all, thus putting energy into the basis of
the plant.
>
> What ever you decide to do, keep taking fotos. Document for
the rest of us!
>
> cheers, Mate,
>
> Jamie
> Cologne
>
> Am 30.11.2015 um 04:29 schrieb Dennis Kramb d*@badbear.com
[iris-species]:
>
> In August I started sowing my iris seeds in ziploc bags with
a little bit of wet potting mix. I put them in the refrigerator
and checked them frequently in the early weeks but then sorta
forgot about them. I just checked them for the first time in over
a month and there's a lot of activity. Here are pics of seeds
germinating from the arilbred 'Rare Breed'.
>
> I intend to pot them up & grow them under lights this
winter and hopefully keep them growing through spring & into
summer. I've never tried this intentionally before but I've done
it unintentionally with Louisiana irises.
>
> Dennis in Cincinnati
>
>
>
>
>
>
>
--
Ralph Carpenter
2 & 3 Stone Cottages
Chilmington Green
Great Chart
Ashford
Kent TN23 3DW
01233 637567
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