last two weeks under mh

i have been growing under cfls the whole time would the last two weeks under mh help or even make a difference any advice please

YEs it will make a difference- how much? couldnt really say- but will make a difference most def- purely for the extra lumens and UVB in the hailde- I use a hailde all way thru Flowering frosts em up nicely- loads more than Sodium.

Hi all

@oll1e - do you think it's better not to use HPS during flowering? I'm 14 days (since sprouted) under MH with my Roadrunners auto and wonder WHEN to swap bulbs for HPS, but after reading your post I wonder IF they should be swapped at all. I've read that you can use MH for last 2 weeks of flowering instead of HPS because UVB (as you mentioned) do the job. Do you think using MH from START to FINISH keeps plants low and it wouldn't be really wanted ones autoplants are generally not tall? It would be cool if someone else wanna share their experience.

bobek said:

Hi all

@oll1e - do you think it's better not to use HPS during flowering? I'm 14 days (since sprouted) under MH with my Roadrunners auto and wonder WHEN to swap bulbs for HPS, but after reading your post I wonder IF they should be swapped at all. I've read that you can use MH for last 2 weeks of flowering instead of HPS because UVB (as you mentioned) do the job. Do you think using MH from START to FINISH keeps plants low and it wouldn't be really wanted ones autoplants are generally not tall? It would be cool if someone else wanna share their experience.

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if your going to use metal halide get a ceramic metal halide bulb that works in an hps setup(they come that way, you have to have a hps ballast.). Dual spectrum hps beats ceramic metal halide which beats normal metal halide. I use the hps for flower, cmh is nice but just doesnt seem to perform as well. i never noticed much height difference, but thats cuz i always train my plants.

original poster-Use both, it will make a difference. not as much as it would of had you added it earlier, but still worth it.

oll1e said:

YEs it will make a difference- how much? couldnt really say- but will make a difference most def- purely for the extra lumens and UVB in the hailde- I use a hailde all way thru Flowering frosts em up nicely- loads more than Sodium.

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MH is closer to the sun´s colour temperature - why bother with sodium anyway??

I think this changing of bulbs has a big dose of BS in it somewhere. Or the grow shops like to sell you two lamps, for some reason ?????.

the sun puts out both sides of the spectrum. a mh is closer to the blue spectrum, which is what most wavelengths of the suns light is put out as in spring with a smaller amount of red and hps is closer to the red wavelengths which the sun puts out as the days start to shorten along with a bit of blue spectrum. It's called the doppler effect i think. Both spectrums are the way to go.

darkdestruction420 said:

the sun puts out both sides of the spectrum. a mh is closer to the blue spectrum, which is what most wavelengths of the suns light is put out as in spring and hps is closer to the red wavelengths the sun puts out as the days start to shorten. It's called the doppler effect.

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Sorry, darkdestruction, that is just nonsense, the sun´s spectrum doesn´t change with seasons. The sun´s colour temperature is a constant 5600K. Because the mostly naive kids who grow MJ will swallow this garbage is the reason we get so much of it.

And the doppler effect is the change in frequency of emitted radiation according to whether the source is moving towards you or away from you.

Obviously you have no scientific training. And don´t try to BS a Physics teacher unless you are very sure of your stuff.

it is only 70 watt mh should i remove the glass sheild ?

MH is high in the blue spectrum which is conducive to growth in the veg phase. HPS is high in the red spectrum which is conducive to flowering. They make a SonAgro HPS bulb which includes 30 extra watts of blue spectrum that seems to provide the best of both.

peff711 said:

MH is high in the blue spectrum which is conducive to growth in the veg phase. HPS is high in the red spectrum which is conducive to flowering. They make a SonAgro HPS bulb which includes 30 extra watts of blue spectrum that seems to provide the best of both.

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And there is the winner! BOTH spectrums are beneficial throughout a plant's life. The reason you have people switching bulbs is simply because they can't or won't hang two reflectors and the added heat. I love my LEDS cause my plants get exactly what they need throughout.

not able to rely on the sun in the uk lol not evan mid summer

Serapis said:

BOTH spectrums are beneficial throughout a plant's life. The reason you have people switching bulbs is simply because they can't or won't hang two reflectors and the added heat. I love my LEDS cause my plants get exactly what they need throughout.

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And you get all a plant needs throughout all of its life from the sun.

lizardlegs said:

not able to rely on the sun in the uk lol not evan mid summer

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Come on, if you want to grow tomatoes where will you put them ??

In a greenhouse or in a dark room with a little light??

Exactly, even the dullest days in the UK produces more lumens than a little light.

I use to HPS at the beginning- loads of grows where I was happy with the end result- Since switching to only hailide not only is my yield the same as using the HPS but the quality wipes the floor with it- My buds are more solid and shit load frostier- Looked into UVB a lot of last two years hence the swop- Never go back to HPS- If anything Id prob use HPS as a supplementary lighting-

Also under the hailide creates shorter nodes there for a better structured lady what more do ya want

Only down side is produces a little more heat .

I think ya said it was a 70 watt MH? urrrrrrr yeah it will still be better than the CFl's , I just thought ya might have a wee 400 or summit- but yeah on ya next grow run it all the way thru or if ya can invest in a higher wattage-

bobek- yeah Keep ya MH going you wont regret it- basically UVB penetrates into the plant, resin is there to protect, the more penetration of UV the more resin it chucks out- Im no scientist but I have seen with my own eyes in terms of how frosty my ladys are now-

MH was out before HPS- and it seems the older daze was when the gooooood was about- co-incedence-

And yeah it should keep the plant nice and short- just remember to get the tops as close as to the light without burning ....

cheers for the info great help ty

Do you think this one was too close to the light? I think leafs edges are rised up. I try to keep it as close as possible to the light but ambient temperature where my box is placed changes during the day so I have to react lifting or dropping the light. Don't know if it was to hot at some stage....?

too me it looks fine- I wouldnt worry- just keep doing what ya doing... bearing in mind further away the light the more ya ladys will stretch-

What strain is it?