MH vs HPS should I be switching back and forth??

Islander · May 17, 2010

Is it still considered to be the best policy to veg with MH and then switch to HPS for flowering? Has anybody tried variations on this?

NugNation · May 17, 2010

That's what a lot of people do. You can run the full cycle with either bulb though. The ideal setup is one with a dual spectrum, i.e. both mh and hps in the flower room.

TheGrowNinja · May 17, 2010

i agree. i think im going to run 2 600w hps and maybe a smaller mh, maybe 400w, mh in a 5x5. but im a newb, listen to the others not me.

Skunkenstein · May 18, 2010

The reasoning behind the Mh for Veg and Hps for flowering is proper color spectrum for the Particular stage of Growth.Mh/Blue Promotes root and Foliage growth..Hps is more of the red/orange spectrum simulating Fall light outdoors.The Blue MH will keep your plants more compact and bushy,wheras a Hps during veg will cause your plants to stretch and slow root growth due to the change in plant Hormones..I would highly recommend the super Blue Hortilux for veg.{Best veg bulb ever}And the Hortilux Enhanced Spectrum Hps for Flowering.If I could use only one Bulb for everything it would be the Super Blue Hortilux.Indica strains tend to respond best to the Mh/Hps combo.If you were running a more sativa strain, Metal halide for the whole run is your best option.

theslums · May 18, 2010

so do u really think the hps for vegging slows thr root growth? is this from experience or reading?

stickygreenman · May 19, 2010

has anyone tried the switchable ballasts? i've seen some hps/mh combos with two bulbs that can be swapped out.

NugNation · May 19, 2010

Most if not all (quantum, lumatek, and nextgen) digital/electronic ballasts are able to run MH and HPS. I personally use quantums and so far they've been working great. I used a MH to veg and then simply swapped the bulbs when it was time to flower, no rewiring necessary or anything like that. just plug and play.

jvotta420 · May 19, 2010

i have a 150 watt hps that i use for 3 of my girls so your telling me that it is gonna be tall and not very bushy would adding cfls help any?

Rysam · May 20, 2010

I use a 1k hps with a regular hortilux bulb for veg and flower. I have a 1k MH but Im a lazy stoner and dont want to go through the hassle of swapping and I dont want to run both. There is no issue growing my 6 plants into 3' shrubs in no time.

TheGrowNinja · May 20, 2010

i have also read many places that a lil mh along with the hps increases potency in the flowering stage...anyone care to validate.

justiceman · May 23, 2010

I have done a 400w hortilux HPS(veg) with a 600w hortilux HPS(flower), and I have done a 400wPSMH(veg) with a 600w hortilux HPS(flower).

For guys that have 10 hoods It seems like more of a hassle to actually switch out every lamp when you flower not to mention the added cost of 10 extra MH lamps for veg.

However I have noticed that when using MH the plants tend to stay shorter and become bushier. While under the HPS for veg they tend to stretch a bit more, although this is strain dependent and environment dependent as well.

I have heard others say if you plan to veg some cuts for 2-4 weeks only then MH will just cost you more, but if you veg seeds it's a nice light to have.

Generally speaking one can use HPS the whole way through and get perfectly fine results but I do know that some commercial farmers that grow veggies and such use MH as primary lighting and then they add secondary HPS lighting during flower so instead of switching the lamps they literally turn on more lamps so that they have both HPS and MH running.

GreenSociety · May 23, 2010

I have also noticed that when using that particular bulb from SunPulse does a phenomenal job at vegging your loved ones.

nebulius · Feb 10, 2012

Experts (including myself, I'm no expert yet) I talked to all use HPS or Super HPS for both cycles. I think going this route is the easiest and cheapest.

squiggly · Feb 11, 2012

Under real-life conditions light comes in as a mixture with variations on intensity at a given wavelength being determined by the angle of the sun in the sky and a litany of other factors I won't go into here. In fall/winter the sun is at a greater angle and more red spectrum/IR gets through, but blue spectrum is still present. Vice versa for spring/summer.

SkunkInTheTrunk · Feb 11, 2012

TheGrowNinja said:
i have also read many places that a lil mh along with the hps increases potency in the flowering stage...anyone care to validate.

What I think your referring too is that the MH light emits a certain wavelength of UV that encourages more resin production, as well as providing a broader spectrum of wavelengths for the chloroplasts (the things that absorb the light energy in the leaves.)

I use a SunPulse 10k bulb for the first week or two of flower as well as the final two weeks, and I see a visible difference in resin production, and it definitely cuts down on the first "bounce" of the canopy quite a bit. If you can get ahold of one, I would give it a shot sometime, see how your genetics react.

P.S. the 10k bulb emits ALOT more UV light, my Irish ass got a sunburn the first time I used it and I went pruning lol :)

outwest · Feb 11, 2012

I'm running a growzilla for the first time with a 600w ushio MH conversion and a 600w hortilux hps. I've dialed in several environmental factors this round, co2, feed schedule, humidity, air flow, etc. . .so it's tough to attribute to much to doubling the lights and broadening the spectrum, but things look incredible. I have a diary that is in need of some new photos. I'll let you know how it finishes.

SkunkInTheTrunk · Feb 11, 2012

That's awesome, I'd love to see the results! I've heard mixed opinions on the dual spectrum bulbs. Some trustworthy growers, who's opinions I value, have told me its not worth the extra expense. However, I'm totally sold on the results of UV and IR from my experience, and I think the plants would dig the broad spectrum. Plants see broader wavelengths than we do, and UV and IR fall just on opposite ends of the visible spectrum, so it makes sense that the plants would make use of this extra energy generated by the sun. Lights, air, and water are more important than anything in a bottle. Good luck!

HydroRocks · Feb 11, 2012

The "best" environment to have is a mix of both spectrum's (MH and HPS together).

sir_diesel · Feb 11, 2012

Hey bro, Iv got a 250w ballast that runs both MH and HPS, I'm running 2 strains that are sativa and with MH in veg they got very bushy, second the HPS was introduced after 2 weeks massive stretch! Iv since added a 250w CFL, but iv taken it out for last 4 weeks because I want the low sun autumn effect for the budding, buds are huge as it is so I'm not looking for anything more but a dank smoke now, only time will tell

outwest · Feb 11, 2012

Excuse the cross post, but here is a link to my updated diary, with the broad spectrum lighting. Enjoy!

MH vs HPS should I be switching back and forth??

MH vs HPS should I be switching back and forth??

Islander

NugNation

TheGrowNinja

Skunkenstein

theslums

stickygreenman

NugNation

jvotta420

Rysam

TheGrowNinja

justiceman

GreenSociety

nebulius

squiggly

SkunkInTheTrunk

outwest

Premium Gardener

SkunkInTheTrunk

HydroRocks

sir_diesel

outwest

Premium Gardener

MH vs HPS should I be switching back and forth??

MH vs HPS should I be switching back and forth??

Islander

NugNation

TheGrowNinja

Skunkenstein

theslums

stickygreenman

NugNation

jvotta420

Rysam

TheGrowNinja

justiceman

GreenSociety

nebulius

squiggly

SkunkInTheTrunk

outwest

Premium Gardener

SkunkInTheTrunk

HydroRocks

sir_diesel

outwest

Premium Gardener

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