Why are you switching that MH out so early?

I've noticed that A LOT of people on this thread jump straight to their HPS bulb when they switch to flowering "if not within the first few days". I'm here to share a bit of advice. Keep that MH on your plant for ADD LEAST the first 2 weeks of flowering. During this stage the plant grows rapidly to ensure sweet and plentiful flowers will be produced. It's a simple concept really. Hps spectrum helps in the formation of dense and plentiful FLOWER production and also some of the plants growth. Notice the next time your plant is induced into flowering how long it takes for hairs to even produce. When these hairs are produced flowers will start to form. Yet these hairs do not start showing "or add least in excessive quantities" until about 2 weeks. By allowing your plant to keep it's focused blue spectrum "roughly 5500k-6200k" it will grow tighter and more plentiful nodes. Which when the time comes will produce rocking bud

If possible, using both spectrum in the entire grow kick some serious ass.

Stay thirst my friends

Agreed! I keep my halide bulbs in until about 20 days into bloom and my plants don't stretch as much as when I flipped my timer and changed my bulbs on the same day. I have also experimented with a Growzilla reflector that holds 2 bulbs. In my Growzilla reflector I ran a 600 watt HPS bulb and a 400 watt MH bulb simultaneously in a 5 X 5 hydro hut and I harvested my BEST BUDS EVER! My buds were denser, tastier and very COLORFUL when I added a MH to my grow room!
Thanks for the advice Titycaca!

It's amazing what the dual spectrum can do. I have both my HPS and T5 lighting my ladies up and the internode spacing is scary.... seriously SOOOO compact it's amazing

Dude! I keep MH AND HPS together in varying amounts the whole time, and therez no doubt in my mind it makes for better buds! More MH than HPS during veg, and more HPS than MH during flower, but both peresent at all times of the grow, and u cannot go wrong... I even have my MH's timed to come on a few hours after the HPS's do, and to go off about three hours before the HPS's do, like sunrise and sunset, in nature... No comparison when sittin product side by side with sum buds grown under str8 MH for veg and HPS for flower... Difference is like night and day... And with the added CO2, I dont know if my plants could be any happier! lol...

Great Post , I was thinking somewhat the same thing. I said to myself I try so hard during veg to keep the node spacing tight , then once i switch to flowering they shoot up leaving gaps between nodes . I veg under a t-5 so I thought to keep her/them under the t-5 for the first two weeks(as stated above) to keep the node spacing tight then switch to my hps.. I thought it made sense just reasurring to see I wasnt try to much..

yep was talking to ppl about this when i first got on here, ppl thot it would be a good "experiment" lol looks like i was in the right thinking, it was my assumption keeping the MH on for the 2 weeks of first flowering for the simple reason of flowers do not show up and start forming till after the 2 week "stretch" or transition. I havent tryed keeping both spectrums for the full grow but what ganjagod says sounds like a REALLY good idea, totally mimics the sun. I have however flowered with a 400watt MH 3200k bulb and had better results then flowering with a 400watt HPS.

I'm glad to hear people are doing this. Other than my new addition to tiger bloom, which has a REALLY REALLY LOW PH, my ladies are doing fantastic with my new light setup. If you guys use ever use tiger bloom be prepared for some serious PH adjustment If I had a working camera I would show you my liberty haze and how close the inter node spacing is. I veg under a 2x2 t5 light setup with 6 6400k blue spectrum and 2 2400k spectrum. Than when I flower I put the t5 on it's side and give some legit side lighting along with the HPS above it.

Anyone else try side lighting? I really like it.

ya i would imagine lots of cfls or LED panels are good for this, LED panels being like ur T5 tubes aswell. I'd like to try it with some CFLs sometime, maybe if i buy another LED panel i could use both of them for side lighting n c how much better those 2 sides come out

GanjaGod420000 said:

Dude! I keep MH AND HPS together in varying amounts the whole time, and therez no doubt in my mind it makes for better buds! More MH than HPS during veg, and more HPS than MH during flower, but both peresent at all times of the grow, and u cannot go wrong... I even have my MH's timed to come on a few hours after the HPS's do, and to go off about three hours before the HPS's do, like sunrise and sunset, in nature... No comparison when sittin product side by side with sum buds grown under str8 MH for veg and HPS for flower... Difference is like night and day... And with the added CO2, I dont know if my plants could be any happier! lol...

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agreed nothing beats a well thought out flowering schedule with the use of multiple full spectrum light sources. at least if your not gonna do hps MH combo, throw some blue cfls in there or some blue t-8 or hell a reptile bulb. limiting yourself to one light is like limiting yourself to one strain.

Yep, and also check out the different types of MH lamps that will fire in their respective kits, that emit a different level of blue, and/or UV-B(which reptile lamps r good for also), but whichever way u go, u wont be dissappointed... Even if u dont have them indepentendly timed like mine... Both at the same time works great, if not better... Id love to add a reptile light for the last few wks of flowering, and throw summa these new-fangled LED kits in there for gits and shiggles, as well... Mabye I'll happen across one sooner or later and give it a go with my current setup...

GanjaGod420000 said:

Yep, and also check out the different types of MH lamps that will fire in their respective kits, that emit a different level of blue, and/or UV-B(which reptile lamps r good for also), but whichever way u go, u wont be dissappointed... Even if u dont have them indepentendly timed like mine... Both at the same time works great, if not better... Id love to add a reptile light for the last few wks of flowering, and throw summa these new-fangled LED kits in there for gits and shiggles, as well... Mabye I'll happen across one sooner or later and give it a go with my current setup...

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I'm planning on adding the UVB bulbs for the last 3 weeks. Turn them on in few hour intervals every day. Have you tried this yet? I have read that the UVB is supposed to increase THC. THC the best sunblock

I finished numerous grows with MH only not too long ago...I like it better than HPS...so I got a CMH for flower. I like it.

titycaca said:

I'm planning on adding the UVB bulbs for the last 3 weeks. Turn them on in few hour intervals every day. Have you tried this yet? I have read that the UVB is supposed to increase THC. THC the best sunblock

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yep plenty of peolpe have tried it. i would just put it on 12/12 with your normal lights the whole way thru nothing your gonna be able to buy are gonna put off the UV of the sun, and plants deal with uv all day.

Didn't read any comments but I agree with the OP. I always leave the MH in there the first two weeks or however long it take till she starts building her buds.

Someday I may get a Growzilla hood and run MH along with HPS in the same hood, but for now I just run HPS (plus T5 UVB), so I use a Digilux lamp with an enhanced blue spectrum at 95,000 lumens. I'm pretty sure that puts out more "extra" blue than half a dozen cfls would. In fact I've been running HPS for veg lately, and to be honest my plants seem to like it better than vegging with MH or CFL. It's true that the internodal spacing with HPS isn't quite as tight as with MH, but the overall growth seems more vigorous in general, not to mention higher lumen output with HPS vs MH for the same wattage.

polyarcturus said:

yep plenty of peolpe have tried it. i would just put it on 12/12 with your normal lights the whole way thru nothing your gonna be able to buy are gonna put off the UV of the sun, and plants deal with uv all day.

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I run my T5 UVB lamp 12/12 along with my HPS, but it's pretty weak. However there are some lamps that will put out quite a bit more, so be careful in over-generalizing.

This light right here will pack quite a punch of uvb: http://www.zoomed.com/db/products/EntryDetail.php?EntryID=109&DatabaseID=2&SearchID=20

as matter fact those are the bulbs i plan on using next grow thx for reminding which particular one it was

as matter fact those are the bulbs i plan on using next grow thx for reminding which particular one it was

And for the contrary opinion, from Ed Rosenthal:

http://www.cannabisculture.com/articles/2243.html

Metal halide or high pressure sodium

By Ed Rosenthal - Wednesday, January 9 2002

What colours do they emit and which is better?

I understand that high pressure sodium and metal halide lamps each offer a different spectrum of light, one towards red and the other towards blue. Which spectrum comes from which bulb, and which bulb is more beneficial for vegetative growth and flowering growth respectively?

"Gotta know to grow!"
Cambridge, Ontario

Both metal halide (MH) and high pressure sodium (HPS) lamps emit most of their light in spectrums which the plants use very inefficiently, yellow and green. Overall, HPS lamps emit more red and blue light, the spectrums that the plants use most efficiently to fuel photosynthesis. Part of the reason for this is that HPS lamps emit 10-20% more total light.

Vegetative plants grown under 1000 watt HPS lamps grow faster than those under 1000 watt MH lamps. There is absolutely no reason to use MH lamps either in flowering or vegetative growth stages. MH lamps are useful for displaying plants.

If you set up alternating rows of MH and HPS lamps you would notice a wave pattern, with more growth under the HPS lamps.
Don't let grower myths or garden shop sales pitches convince you to buy unneeded equipment. Your best light source is a 1000 watt HPS lamp.

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Apparently he's had some evolution in thought on this topic over the last few years. More interesting stuff on this here:
http://www.cannabisculture.com/v2/articles/2833.html

And here:
http://www.cannabisculture.com/v2/node/10584

MH VS. HPS LAMPS
What are the pros and cons of metal halide (MH) and high-pressure sodium lights (HPS)?
Kellen,
Internet'


MH lamps produce less light than HPS lamps and less is useable by plants, which use primarily red and blue light to most efficiently power photosynthesis. Therefore, growth under MH lamps is slower and yields less. On the other hand, MH lamps have a less conspicuous and suspicious spectrum than HPS lamps.


MH lamps emit more UVB light than HPS lamps. In high quality marijuana plants the percentage of THC (and probably of the terpenes) increases in direct ratio to the amount of UVB light the plant receives. The result is that buds ripening under a MH lamp have a higher THC content than those ripening under an HPS.


One way to take advantage of the qualities of both lamps is to use ballasts that can accept either lamp or to use conversion bulbs. During the vegetative and most of the flowering stage use HPS lamps to promote growth and yield. Then switch to MH lamps for the last two weeks of flowering to increase potency.

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Jogro said:

And for the contrary opinion, from Ed Rosenthal:


Apparently he's had some evolution in thought on this topic over the last few years. More interesting stuff on this here:
http://www.cannabisculture.com/v2/articles/2833.html

And here:
http://www.cannabisculture.com/v2/node/10584

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Thanks for the post. I was hoping to get some information about the other side. I Kind of just realized that I don't even own a MH lamp "I know i know" I'm rocking t5 and I always will. The inter node spacing with T5 is just insane compared to what i've seen with MH. Maybe it's just my phenos, but who knows. Anyway The one thing the Ed seems to not mention is the spectrum ranges emitted by both MH and HPS and how the plant utilizes the spectrums. I'm not expert, but there seems to be a wide study of what spectrum does what for a plant.