glass in air cooled reflector

[unlockit]

iv read a page in cannabis culture jan/feb 07 that says the glass will absorb most of the uvb light thats responsible for increasing thc at the end of the flowering stage. it also says that there is a special kind of glass that dosent but dosent say what it is. i would like to go with 3 600 watt air cooled digital enhansed hps and because of the 30% more blue light in the enhanced hps will that be enough uvb to use the standard glass?? any help thank -u -

[Earthy Dank]

Thats interesting... Those digital HPS's are cool as shit... I wish I was rich...

[Tomthehippie]

not for getting that the bulb has got a glass casing.. i really wouldnâ??t worry about
ubv light - ul be able to grow it strong enough with the current equipment on the market! :)

[Al B. Fuct]

I'm with Tom. I wouldn't stress too much about it. Old Sol puts out a fair whack of UV, but so do HPS lights. My 1000HPS lights will bleach, make brittle or disintegrate non-UV stabilised plastics in my op in just a few months.

Some modern window glass does have various UV & IR filtering characteristics, but you generally pay extra for it. All the same, I'd avoid using glass in an aircooled hood that was specifically labelled as blocking UV.

If you buy a cut pane of plain ol' common cheap window glass from the hdwe, you're not apt to get anything you're not paying for. ;)

HPS tube envelopes are usually borosilicate glass (http://en.wikipedia.org/wiki/Borosilicate_glass), which is about 95% transmission efficient in the UV end (250nm), dropping sharply in transmission on the IR end. Many people are making cooltubes out of Pyrex Bake-A-Round tubes, which if made before 1998 (http://en.wikipedia.org/wiki/Pyrex), are also borosilicate glass. "Vintage" Bake-A-Rounds are commonly available on Ebay.

Common soda-lime (http://en.wikipedia.org/wiki/Soda-lime_glass) glass is no slouch in passing UV, about the same as borosilicate.

[Celeste]

i just purchased a 26w uvb cfl from petsmart. it cost 15 dollars, i'll be trying it this go round. i've noticed that my plants outdoors are much more packed with crystals than what my indoor babies do, so i figure it can't hurt....

all will be revealed in my thread....

love, lestie


http://boards.cannabis.com/hydroponics/118654-lesties-adventures-water-works.html

[Al B. Fuct]

I'd sooner blame poor resin production on other conditions, more basic than UV exposure, stuff like getting temps and RH to stay in range as well as avoidance of overwatering. It'll be hard to tell if your CFL UV really changes anything unless you have a pair of identical grows, one with and one without added UV- but it probably won't hurt much.

[Tomthehippie]

i just purchased a 26w uvb cfl from petsmart. it cost 15 dollars, i'll be trying it this go round. i've noticed that my plants outdoors are much more packed with crystals than what my indoor babies do, so i figure it can't hurt....

all will be revealed in my thread....

love, lestie


http://boards.cannabis.com/hydroponics/118654-lesties-adventures-water-works.html

Ur out door grows will always be better as you have the sun - a natural full spectrum of light unlike artificial lights indoor that only has a limited spectrum

[Al B. Fuct]

Tom, I've seen some lighting systems that use BOTH an MH & and HPS (http://homeharvest.com/hydrofarmradiantgrowzilla.htm) in a single light fixture. This would have to come prit-tee darn close to full sun spectrum.

However, cannabis plants just don't need much blue in flower nor much red-yellow in veg. Some plants might make good use of the twin lamp setup, but I don't think cannabis is one of them.

[Tomthehippie]

yea man iv seen them 2 - they look pretty cool! i use a interchangeable system use mh for veg and hps for flower :)

[unlockit]

cool