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2013 Archived Messages


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MONTHDATEDATEDATEDATEMONTHDATEDATEDATEDATE
January 1-7 8-14 15-21 22-31 February 1-7 8-14 15-21 22-29
March 1-7 8-14 15-21 22-31 April 1-7 8-14 15-21 22-30
May 1-7 8-14 15-21 22-31 June 1-7 8-14 15-21 22-30
July 1-7 8-14 15-21 22-31 August 1-7 8-14 15-21 22-31
September 1-7 8-14 15-21 22-30 October 1-7 8-14 15-21 22-31
November 1-7 8-14 15-21 22-30 December 1-7 8-14 15-21 22-31

8—14 October


From: Geoff Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] LED lighting...
Date: Wed, 09 Oct 2013 18:15

Phillips in Eindhoven, NL make a range for professional horticultural use, and it is one of this range which − after some thought- I am going to start with.
The guarantee is for 3 years, and the anticipated life is some tens of thousands of hours. So I have no fears on some issues.
After getting lost with Avrogadro's Hypothesis ( now understand that, but can't see what it has to with the subject) , and understanding faintly that the Bose-Einstein condensate might, but still failing to see at all how it can be applied, I have abandoned attempts to use maths to design a practical application, and intend to rely on good old suck it and see.....

Geoff

Sent from my iPad

> On 7 Oct 2013, at 21:42, "Ed Deckert" wrote:
>
> Hello Geoff,
>
> I have no experience with these LED fixtures, but have seen them
> for sale on ebay. Most, if not all of these fixtures seem to be
> made in China, and customer reviews have not always been stellar.
>
> You mention using these LEDs in your greenhouse, and that gives me
> cause for concern from the standpoint of humidity. It would be
> good to know the operational range of these fixtures as far as
> humidity is concerned. Many of these fixtures are used inside of a
> residential house for plant cultivation − one particularly popular
> use is for growing cannabis. "Pot" houses seem to love these
> lamps. And the humidity levels there are likely far less than in a
> greenhouse.
>
> I would have concerns about potential electrical shock hazards, as
> well as dampness degrading the electrical connections or possibly
> the LEDs themselves. I recently purchased several LED bulbs to
> replace some burned-out bulbs in the house, and they came with the
> caveat of not using them in damp locations. Of course, your
> mileage (perhaps kilometerage?) may vary.
>
> Mind you, I am not speaking from knowledge, but am posing some
> hopefully valid concerns. Please do share what you find out.
>
> Regards,
> Ed

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From: tony garthwaite
To: Orchid Talk List
Subject: Re: [OrchidTalk] LED lighting...
Date: Thu, 10 Oct 2013 09:00

Geoff,

See bottom of page15 in The Times today, 10/10/13.

Or follow up lead to Stockbridge Technology Centre and 'growing lettuce
under LED lights!

Here's a link!

http://www.stockbridgeonline.co.uk/category/led4crops/

Tony G.

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From: Geoff Hands
To: Orchid Talk List
Subject: Re: [OrchidTalk] LED lighting...
Date: Fri, 11 Oct 2013 13:50

Thanks for that Tony. I have spent a lot of time studying everything I could find on LEDs, Phillips info ' being particularly helpful.
The only real problem is knowing how much LED power to apply (like wattage) and at what kind of power per sq.ft. Inverse square laws are not much use with devices without lenses or reflectors − although Phillips are now producing some with these features.
And it is one thing to do a trial with a few pounds worth of lettuce seed, another thing altogether to put them above a bench of multi- growth paphs, with a far greater value...

One of the really interesting bits of info I picked up is that plants do not in fact make use of the whole spectrum of white light. Different processes require different wavelengths, so clever old Phillips produce LED sets of say 100 individual diodes, each tuned to a particular wavelength, so that (say) 10 of them are at the frequency wanted for ATP manufacture, 20 at what is wanted for sugars, and so on.

I had hoped for someone to chip in and tell me they had tried some particular unit, and so giving me a shortcut to what I might need, but that is not going to happen it seems.

Geoff

Sent from my iPad

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From: Tina Stagg
To: Orchid Talk List
Subject: Flowering now
Date: Mon, 14 Oct 2013 16:10

Not much in flower at the moment but this is an interesting one: dendrobium kentrophyllum.

It’s growing intermediate with plenty of water. This is a first flowering from a small plant acquired about two years ago. It’s in a 5cm pot and the flowers are about 3cm long and are lasting well.

Tina

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