MH vs HPS in bloom

the gnome · Aug 3, 2012

its been talked about to no end
but Ive yet to see it done.... easy is it seems?
Ive heard all about MH gets you more resin and less stretch etc etc but personally haven't seen the proof?

my last few runs in my 2000w grows i have been starting to use 1 Mh bulb in the bloom phase after 5 wks to see if resin production increases.
its very inconclusive after 2 runs.

on my current(3rd) run I decided to leave the Mh in from the onset of bloom
now I'm seeing a very noticeable difference!
has anyone else run a side x side with Mh+hps?

the plant in Q is landlocked so to say in its current state and chop is this weekend
BUT
there will be an obvious difference to discuss!

vapedg13 · Aug 3, 2012

i only use mh all the way through the my grows never use hps....used to use it years ago but not anymore

Karmic Farmer · Aug 3, 2012

Very nice Gnome, thanks for the post! You may also want to try adding a black light or reptile bulb instead as an experiment because they emit uvb which is what causes the noticeable increase in trichromes and are much cheaper to run. I'm sure there are other benefits to the MH with increase in the blue spectrum keeping the nodes a little tighter and more compact. I'm thinking of supplementing with a MH or something else just to see myself.

Peace,
KF

sso · Aug 3, 2012

i see an increase in trichromes adding a few 6400k cfls.

so im wondering if its the added blue as well.

the plants look nicer as well, with some blue in the grow.

Karmic Farmer · Aug 3, 2012

The added blue spectrum definitely adds to the overall structure in the flower cycle. If I'm not mistaken UVb can damage the plant, or inhibit it in some way then the plant produces more trichomes to protect itself. Something about pure highland strains having a special effect not seen in the lowland varieties has been attributed to the higher altitudes which have a much higher concentration of UVb.

Peace,
KF

DrFever · Aug 3, 2012

this is IMO what happens when you use MH in flowering is you get more leaf structure in the bud
As for resin production one must learn environment problem is growers read dropping humidity in flowering phase which is correct but drop it slowly when dropping it to fast you create a world of all kinds of stress , and plant problems here resin production at its finest ending week 5 HPS grow temps 84 - 86 lights on humidity 65 - 70 slowly dropping to min 55- 60 for harvest

Stonefree69 · Aug 3, 2012

Wouldn't hps yield more though? I heard a combo of 2:1 hps in flowering is best. Guess a Reptisun w/250 µW/cm² radiation could also give those trichomes a little boost.

DGSIX · Aug 3, 2012

I have definately noticed the differecences between flowering under hps and mh. Yes, hps makes your buds a little more dense so if it's commercial appeal you seek, then yes, buds will be heavier. MH your buds are little more compact and lighter but i think pack on as much trich coverage as the big buds under hps if not more. Connoisseur (mh) or Commercial (hps).

-DG-

Green Supreme · Aug 3, 2012

I like a 1:1 mix of both. Peace GS

growshopfrank · Aug 3, 2012

Stonefree69 said:
Wouldn't hps yield more though? I heard a combo of 2:1 hps in flowering is best. Guess a Reptisun w/250 µW/cm² radiation could also give those trichomes a little boost.

HPS defiantly yields more we did an trial with 2 HPS 1000 with a MH 1000 in the middle over 4'x8' flood tables VS 3 HPS1000 over the same and the results were that the mix tended to be around 1/4 elbow less with the mix and with blind somewhat subjective testing no noticeable difference in quality this is with testing about a half dozen strains

PS the MH light spectrum sure makes the buds LOOK more resinous

growshopfrank · Aug 3, 2012

Green Supreme said:
I like a 1:1 mix of both. Peace GS

if you are an old school fucker with a sun circle that's a good ratio

Green Supreme · Aug 3, 2012

Bare bulbin baby. Peace GS

the gnome · Aug 3, 2012

glad to see all the intrest in this subject,
it struck me last week looking at the plant in Q:
Diesel#1/Abusive OG Kush-(mom) X Chem BX2-(sire)
that is was right in the middle between the 2 cooltubes.
now, when i put it in veg i had to top it, it was already over 6ft..
so when i did they did the stretch(both fairly evenly) and each side went to the corresponding lamps so unwittingly I was perfectly set up to do a side by side

like i said, its locked in tight with other plants and I'll get some good pics of the difference between the HPS and MH's effects on the same plant

theres another thing I noticed the past few nites, this is very preliminary and will take more testing,
BUT
it looks like I may get a bit faster ripening under the HPS
I seem to be getting milky faster, again on a plant a plant in the middle on the other side of the cooltubes of the secret recipe strain

more to come on this too

psyphish · Aug 3, 2012

Metal Halides? How about ceramic metal halides. Great light spectrum & loads of uv-b. So far I'm very pleased with mine, I use it for both veg & bloom.

vapedg13 · Aug 3, 2012

all mh all the way

944s2 · Aug 3, 2012

growshopfrank said:
if you are an old school fucker with a sun circle that's a good ratio

hiya, this old fucker uses sunmasters 600w dual spectrum bulbs ,best of both worlds,,,peaceand safe growing s2

DrShio · Aug 3, 2012

Check out Sunmaster Warm Deluxe (3000k MH) or the Sunpulse 3k. You get the best of both worlds IMO. I use a mix of Warm Deluxes and Cool Deluxes.

I believe the use of HPS stems from outdated lore. People started using them when indoor growing first started because they had the highest output of any bulb available, in the best spectrum (metal halides were junk). The metal halide technology has progressed considerably since then and has far surpassed the HPS.

People think that stretch happens during flower because they switch their plants from MH to HPS and their plants freak out because the HPS lacks so much spectrum. What the plants are really doing is trying to find the light (even though HPS provides a lot of light, it is not in the right spectrum the plant wants).

But here is the reality:

Each plant is bred a certain way and has genetic predispositions. Therefore the light the plant wants will highly depend on its breeder and genetics. If the breeder selected for largest yield using only HPS, then the plant will likely do best in all HPS. This is the same for fertiization - if the breeder selected for which plant thrived most using synthetics, it will perform best with synthetics - if the breeder used organics, it will perform best with organics.

EDIT: Also, I think that dual-arc bulbs are a sham - you only get a 600W HPS and a 400W MH in a bulb - now place that at 1000W distance (due to 1000W heat) and the light hitting the plants is WEAK. Its like using a 400W MH next to a 600W HPS 18-24in from the plant, not okay.

vapedg13 · Aug 3, 2012

some of my plants tops are 12 inches away from my 1000 watt bulb.... 400 like 6-8 inches away

DrShio · Aug 3, 2012

Yes, I run my lights close as well - under 12in at the tops as long as it isnt at a hot spot. I was hyperbolizing the effect, especially for the secondary's which might not be right at the top. Anything that is far away is that much more ill-affected by the dual-arc.

FunkBomb · Aug 3, 2012

Vapedg13 - that picture of the single plant is great. That thing looks like an absolute monster. Do you use a certain kind of MH, or just the normal 4000 kelvin ones? Those plants look really good, can you tell us about your growing style?

-Funk

MH vs HPS in bloom

Active member

Member

Active member

Active member

Active member

Active member

Veg & Flower Station keeper

DGSIX

Well-known member

Well-known member

Well-known member

Well-known member

Active member

Well-known member

Member

Well-known member

New member

Member

New member

Power Armor rules