ok.. while doing some research i came across an interesting article..

Ed Rosenthal (14 Jan, 2005)
Can I switch to metal halide during the last few weeks of bloom?
For years I've been growing under high pressure sodium (HPS) lights for both the grow and bloom phases, because HPS lamps emit more useable light per watt. This results in a better yield.

However, UV light stimulates resin production and metal halides (MH) emit more UVB light than HPS lamps. The bud has pretty much stopped growing by then so the reduced light output of the MH would not affect yields too much. Does it make sense to use MH lamps during the last few weeks of the bloom to stimulate more trichome/THC production?

Or is there a better way to add UV light to the end of the bloom phase?

Budleigh,
Charlottesville, Virginia


Potency increases with more UVB light, so it would be a good idea to increase the amount of UVB they are receiving.

I like your idea of replacing the HPS lamps with MH during the last one to two weeks of flowering. Your reasoning – that flowering growth has slowed so that MH lamps, which emit considerably more UVB light than HPS lamps, would increase the quality – could work. It's worth a try.

You can also supplement UVB light with a reptile type light found at most pet stores.

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may try that this harvest myself with a couple..... i usually stick my inside flower outside if it is around that time of year because the outdoor is ALWAYS stronger. but i only leave the m out for about 6-8 hours of their 12/12 cycle.

i use a dual-spectrum light (600w HPS/ 400w MH ) through the whole grow... don't know if it matters or not but i like the results...

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Grow Journals
The latest-> White Berry Big Bud/PPP PPP

Dudes. There is a crazy new bulb on the market that is meant for the last week or even two weeks of flower. It emits an insane amount of UVA light to the plants (10,000k). i just bought it after my local grow store guy was raving about the amazing things it has done to his plants. It's only made by 1 company right now. I can link what i have to show you; their light chart (scroll all the way to the bottom, its the 10 kelvin one on their product list). You may be able to buy a bulb from them, but probably not. There are a few stores that sell them now(but only one store in 100 miles of me), and people say how amazing they are. Has a pink/purple flashing glow, bulb is insane looking.

Guy at store told me that it makes the resin and crystals multiply by 10. Im about to experiment with it in the next few days.

The bulb is made by LifeTech - http://www.lifelighttec.com/f/LLI_Fa...cingWeb_B1.pdf

you sure its UVA? cuz from what i heard....UVA will kill your plants.


UVB is what you need!!!

a jon,MH bulbs do work alot better for resin production,way better!Plants dont stop growing the last two week its the opposet,they grow the MOST during the last two weeks.Its best to add a MH or a uv bulb.Loudblunts if uva killed plants we wouldnt have any the sun puts out alot of uva rays.Yota how much did you pay for that bulb?Its just a ceramic metal halide bulb i believe,they've been out for a year or so now.Yes the 10k is suppose to be AWESOME for the last couple of weeks of flower.I usally use a hortilux blub,it has 30 percent more blue light and way more lumens than the standered bulb,its always work VERY well,i believe i need a new bulb so i swiched out the hortilux for a reg MH(the last two weeks of flowering)it worked awesome the crytals are better then usally.The next bulb i buy is going to be the Reto-fit ceramic MH bulb,it works in stander hps fixture.Ps it wont work with the digital ballast only the coil ballast.Hes a link>>> Phlips MasterColor Ceramic Metal Halide ~ CMH ~ HPS-Retro White Stay Safe!!

ronbud - the bulb was about $115 bucks.

loudblunts - I'm sure it is UVA, it says so on their light chart as well. And yes, that much UVA does kill your plants. That's what it is supposed to do. Stress and basically kill your plants while increasing resin and crystals, and colors. Thats why you only use the last week, or possibly 2 at most. Im told your plants will do some funky shit during this time. Ill see this week

ronbud, why is it that they call them ceramic metal halide, when they can be HPS also?

thanks for confirming yota....


could ya keep me posted on your progress? perhaps a pm?