Keeping stuff alive in the arctic blasts

Worth reading the Cannabis forums, those boys have it down to a fine art. Incentivised by the high value of their crop of course

I have Metal Halide for taller / bushier plants that need canopy penetration. Lots of heat so has to be 18"-24" away from plants, and high wattage/high cost (but covers quite a wide area, so not THAT disproportionate, wattage-wise, to fluorescents), and I have tubes for seedlings - I get the tubes to within an inch or two of the plants (tubes are relatively cool). I don't have LED yet, but I think you can get away with a lot less Lumens by having specific light spectrum that the plants need. LED, too, need close proximity to plants, so useful for seedlings. Once plants start to grow the varying heights makes fluorescents more tricky - I have things propped up on upturned flowerpots to try to get even canopy "top" so I can get the tubes close ... but the blighters continue to grow!

I wish you hadn't said that, then I could of got the "@JWK grows his plants on Gas Mark 5" gag out, which I think needed an airing

 

@JWK
I see that your seedlings (on gas mark 5 :-) ) are shielded from the light of the CFLs by what looks like a re-purposed shelf or did you have others directly under them?

@Kristen
Are there tables/lists available detailing the spectrum required for different plants?

 

Hi @JWK
What I meant was:

 

OK thanks JWK and yes I can see why you made your own as £85 is a tad steep.

@Kristen
In post #31 you wrote:

"Worth reading the Cannabis forums, those boys have it down to a fine art. Incentivised by the high value of their crop of course "

Have you seen the BBC local news today?
http://www.bbc.co.uk/news/england/london/
Scroll down to 1527 (top right hand corner) and what do we see?

"Police have discovered a large cannabis factory in Crystal Palace.....
......Inside the house the officers found 500 cannabis plants with four rooms set up with ventilating and heating equipment."

 

Well, according to the news report, you got careless and were moving the "merchandise" in large quantities inside bags and putting them in a wheelie bin.
You should have rather used supermarket bags.

 

Dave - CFLs are simply fluorescent tubes. However I understand that they are slightly less efficient than a tube. The reason is that a tube is less efficient at the ends - so the longer the tube the more efficient it is, but EFLs are only short tubes.

Our government says that EFLs are 5 times as efficient as the old incandescent bulbs. I understand the US government only allows companies to claim them to be 3.5 to 4 times as efficient. I think this may explain why many people claim that CFLs are less bright the equivalent old bulbs even after they have warmed up. For instance an 11 watt CFL package in this country says it the equivalent of 60 watts ie 5.5 times as much. In the US it would be classed as equivalent 38.5 to 44 watts.

 

Hi PeterS

Interesting points.
I have never bothered to check what the legal efficiency claim is here but will certainly do so.

I had always assumed that CFLs are very similar to fluorescent tubes with the major differences being added electronic drive circuitry and phosphor coatings which affect the light spectrum given out and that CFLs actually give out more UV than their fluorescent tube counterparts.

From wikipedia ( http://en.wikipedia.org/wiki/Compact_fluorescent_lamp ) :

and:

 

Problem I have with CFLs, used for plant lighting, is that you mount them horizontally and put a reflector above them then half the light goes into the middle of the tube arrangement, so has quite a lot of distance to travel to either bump into another tube, or then eventually reflect from the reflector above. Much easier to build a light box using Tubes such that the tubes are really close to the reflector above

I think best use for CFLs is "dangling" above plants just to provide enough tick-over light for the winter (if there is little heat then their won't be much growth, so for real growth need both heat and lots of light). For seeds I would do Tubes or LEDs and for foliage stuff Metal Halide