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:
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> 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.
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> 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.
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> 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.
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> 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.
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> 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.
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> ciao für now,
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> Jamie V.
> Cologne
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> Am 04.12.2015 um 21:48 schrieb Walter Pickett w*@yahoo.com [iris-species]:
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> 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
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> On Monday, November 30, 2015 2:07 AM, "Jamie j*@freenet.de [iris-species]" <i*@yahoogroups.com> wrote:
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> 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.
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> What ever you decide to do, keep taking fotos. Document for the rest of us!
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> cheers, Mate,
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> Jamie
> Cologne
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> Am 30.11.2015 um 04:29 schrieb Dennis Kramb d*@badbear.com [iris-species]:
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> 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'.
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> 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.
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> Dennis in Cincinnati
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Ralph Carpenter
2 & 3 Stone Cottages
Chilmington Green
Great Chart
Ashford
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