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I need advice with HPS/MH lighting


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#1 Zlatokrt

 
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Posted 25 September 2011 - 18:38 PM

Hello,
as i have counted how much would i spent for heating of my greenhouse during winter, i decided that building of a small version of Sativ`s growroom in our basement would be much cheaper. I was thinking about approx. 2 m2 of growing area, which should be enough for my plants (mostly sundews, helis and utrics). I have everything planned, except lighting.
I am thinking about 250 W HPS light, do you think, that it would be enough? Or would be MH light better? I do not have any personal experience with these types of lighting. And which one to choose? I have seen lights from Sylvania, Osram, Philips, GIB, SuperPlant, PowerPlant... Any good experience with any of them?
Thanks in advance for any advice
Adam

#2 fly guy

 
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Posted 25 September 2011 - 19:54 PM

Hi, I've got a kind of small version of Sativ's place. I tried some of HPS and MH - I do prefer MH, however its durability is a few times worse than HPS. MH advantages - less heat than HPS, light easier to bear for my eyes. Disadvantages - efficiency (in time) and durability.
MH - I discourage to buy GiB, I had a few, all of them broke in 3 month period. Got free replace - the same happened.
HPS - you can go with Philips.

Link for my setup:
http://www.rosliny-o...showtopic=11954

#3 mobile

 
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Posted 25 September 2011 - 20:59 PM

Last time I looked, HPS were more efficient than MH, with approximately 50% more lumens/watt. HPS are biased to the red end of the spectrum, which is good for photosynthesis but the lack of blue can cause long internodes. To alleviate elongation, a mixture of HPS and MH can be used, as MH has more blue. Check the spectral graph for the lamps you are considering and compare how much output is in the chlorophyll absorption bands.

#4 Amori

 
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Posted 26 September 2011 - 09:39 AM

I used to always use the Sylvania Grolux bulbs (HPS) as it purportedly has an added blue spectrum. Still a very orange light, but it was brilliant for luscious growth.

Edited by Amori, 26 September 2011 - 09:39 AM.


#5 Zlatokrt

 
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Posted 26 September 2011 - 10:34 AM

Thank you for opinions.
I made some search according to your advices: truly, almost all HPS have the most light in yellow/red and only a very few in blue. However, Osram HQI-T (which, as i understand it, is a MH) has a very nice spectre (complete from blue to red) and Sylvania grolux seems to be the best - it is dual spec bulb, so the blue part is enhanced.
So it is decided, i am going into Sylvania SHP-TS 250W Grolux, which is easy to buy and seems to be very good for plants.
Thank you once more for your help :smile:
Adam