Topic: Lighting

[Good Gourd 2]

What is the cheapest form of lighting for 3 onions in a green house. Please.

[gavinjconway]

Please elaborate... is this to overwinter them? and is the lighting for heat? etc...

[pumkinlover]

maybe they are scared of the dark ;)

[cornykev]

Maybe a teddybear would help.   :D

[daveyboi]

Maybe a teddybear would help.   :D

Kev you always manage to raise a smile...

If it is just light to see by rather than grow by any form of LED solar light would be free to run.

[chriscross1966]

I think you need a definition of cheapest..... LED's over the long haul win simply because they are for the long haul... compact fluorescent is probably the cheapest setup costs though.... with LED's you'll probably have to make the fixture yourself, unless you trust the junk I've seen on ebay more than me, and good luck getting any sense out of places where growlights are normally discussed.... THat siad LED will be cheaper per lumen to run if you have an efficient DC converter, or you could even run it off solar panels and a small wind-turbine running into a leisure cell, with some electronics to make sure you didn't run the battery flat....

Unless you want to go on the online magical mystery tour I went through last year trying to find any info that was useful about LED's I'd suggest CFL simply cos it's simple....three onions should fit in a double seed-tray and I expect you could build a foil tent around them (and foil under them too) and use a 25W CFL... LED's could run half the power and make a lot more "useful" light, but really it's lot a lot of juice either way... and you'll have to build the LED's for yourself....
you will put an RCD in the circuit won't you?.... thank you...

[pumkinlover]

Please tell me why???

three onions in a greenhouse  :-\

There has to be a point to this excercise :) :)

[Good Gourd 2]

The point is I have a very small greenhouse there has to be at least 18ins all around each onion, and hearing that they should have 24/7 lighting I am un sure as to what kind of lighting etc I could use,  that would be easy to rig up.  Would a daylight bulb fitted to an ordinary bayonet work or are there special bulbs, the heat is not the problem.

[GodfreyRob]

The point is I have a very small greenhouse there has to be at least 18ins all around each onion, and hearing that they should have 24/7 lighting I am un sure as to what kind of lighting etc I could use,  that would be easy to rig up.  Would a daylight bulb fitted to an ordinary bayonet work or are there special bulbs, the heat is not the problem.

Never heard of onions needing light 24/7.
Whatever way you do it these 3 onions are going to end up being worth 10s of £ each.
(even if it was a typo and we are talking about tree onions)

Waitrose is well lit at this time of year - and they do organic onions ;)

[pumkinlover]

Are you trying to keep them growing all winter to get huge onions GG?

[Good Gourd 2]

Thats it, just a train of thought that granted is not a very good one but thought it was worth a try.
Back to the drawing board. Managed to get em to 5lbs  just a couple of ozs extra.  :D

[pumkinlover]

I bought some LED's last year to start things off early- see posts by Allabout LIverpool.
Personally I did not do very well, probably my fault, I'm going to try them over a rescued fish tank to grow salad leaves over winter (hpoefully!)
Good luck with the onions!! :D

[chriscross1966]

What sort of LEDs are you using.... You'll need high efficiency red and blue, don't bother with the stuff from Maplins, they haven't got the efficiency.... you don't need the 3W luxeon/lumiled/CREE monsters though, they run their cavities hot adn lose a lot of efficiency even if they are very bright for the amount of space they take up.... I reckon 10mm 100mA are probably the best bet, won't run too hot and you won't need to solder up too many of them.... IIRC you can get two of each in under 12V and control with not too much resistance (therefore not too much wasted power)... of course if you build up a fixture with two of each in each of ten sticks and get a cheap 1A 12V switchmode controller it should just work.... that's waht I'll be trying... fingers crossed.....

[pumkinlover]

http://www.allotments4all.co.uk/smf/index.php/topic,35848.msg663561.html#msg663561

They did not do much in that set up but they are blue and red, so I'm going to have a go over the fish tank. I love other people's cast off's!!!

[Kleftiwallah]

A 4 foot Growlux tube should do the trick.     Cheers,     Tony.

[Tee Gee]

The 'big onion/leek' growers build cabinets of a size suited to the size of pot they are growing in.

They line these with with tinfoil and and fit a 'daylight' strip light  vertically on one side (sometimes both sides in big cabinets) then close the door (which is also lined with tinfoil.) and leave the plants to get on with it.

I am not sure if they 'light up' 24/7 but most likely the lights are on a timer.

Years ago when I grew 'big uns' I didn't use a cabinet I only used an overhead strip light set to come on two hours before sunrise and go off two hours after sunset.

This worked for me.

I had a friend who had an old pool table in his cellar complete with light canopy and he fitted a soil cable to the playing surface  which he grew all sorts of things on.

I do recall asking him once; did he have to keep putting ten pences in to keep the light on like you do when playing a game of pool.  ::)

[Morris]

This thread was a roller coaster read - made me lol - several times - and get brainache - feel I need a little lie down now ...

Never managed to get my head around greenhouse lighting, the technicalities completely lose me, I don't speak even half the language of that obscure world  ;D ;D

[Nigel B]

You can safely forget led's. Simply not worth the expense or effort.
Try a cfl or even a daylight fluorescent strip or two. They emit a broad spectrum of light the plant can actually use.
If you really want some light, go with HPS or MH bulbs, like you see in overhead lighting..... and don't forget, heat IS light and vice versa. LED's produce little heat because they produce little light.
Daylight fluorescent strips and a cheap timer from b&q's are pretty much guaranteed to provide the light, and heat, you need. Personally, I'd start with the lights on for 18 hours and off for 6. Like in high-summer.
Hope this helps. :) Have fun.

[chriscross1966]

I'd respectfully beg to differ on some counts of your post Nigel, however TBF, a cheap timer adn a daylight CFL is the simple way to do it and the cheapest to set up and 18/6 (or maybe 16/8) would seem sensible..... however...

I deal with LED's in my job (and as my degree was combined microelectronics and biology I get he bio side covered as well) and they are simply the most efficient way of producing light known to man, hence they waste little energy (as heat), also as plants only absorb red and a bit of the blue spectrum of light (which is why they're green, it's the reflected light) it's easy enough if you know how to read the specs to tailor an LED array to to chlorophylls absorption.... indeed you can concentrate on maximising the efficiency of the LED's as chlorophyll is pretty forgiving on the red end and the blue end is happily peaking pretty much bang on the most common blue LED emission colour.... the issue with LED's is efficiency in the driver circuit...

THe common myths around LED's seem to concern the use of LUMILED and other high-power devices... high power and indeed high-brightness at high power doesn't mean efficient, they're not, they're just bright, but the same amount of power could make a lot more light spread over a bigger area of production and be more efficient simply because nothing is getting as hot.....

I'm going to use LED's for an experiment, I'd suggest anyone who just wants to get up adn go with lights to use CFL....

Cruising the web for info just tends to lead to the sort of sites where people who grow dope sit around and argue... to call their understanding of chlorophyll woeful leaves few words left to describe their understanding of LED emission cavities, optical physics, the second law of thermodynamics, optics and electrical safety.....

[Nigel B]

I'd respectfully beg to differ on some counts of your post Nigel, however TBF, a cheap timer adn a daylight CFL is the simple way to do it and the cheapest to set up and 18/6 (or maybe 16/8) would seem sensible..... however...

Hi Chris. Sorry I missed your reply. I didn't mean to be rude. I have a couple of old CFL 'Envirolights' of 125Watts each which I'm about to use to extend the life of a chilli plant I particularly like, and to get an early start on allotment stuff if I can. I might try a big onion or two if I can lay my hands on a couple of seeds.
Aaaanyway.....

I can understand what you're saying here Chris, but the problem with LED's has always been one of poor penetration into the canopy of the plants. I have yet to see an LED grow that has produced a decent-sized plant that isn't a rather spindly version of what it should look like. Not that I've seen many LED-only grows, but the few I have have turned out as above.
I'd be fascinated to see what you can do with them though.  I'm always willing to learn.   :)

Light is heat, heat is light..... light is heat.... heat is light..... ;)