MH vs HPS

Im currently vegging under a 400 w HPS, i know there is a reason people veg under MH and i know i should get one but my question is how much faster will my plants veg under this 400w mh than the hps and is it worth it to buy one?

They will be taller and strtchier under the hps for veg, VS smaller and bushier under mh

If your running mostly indica strains or hydrids it doesnt really matter sativas you would
have to lst basically tie the branches around the pot.

OK this is the foundation.


Here's an HPS spectrum (Hortilux) against their somewhat different plant response spectrum. Note the severe deficiency in blue light.



Here's a 400 MH. Spiky but good red/blue ratio for veg.



A Hortilux 1000. i don't know if I believe the radically better fill-in relative to a 400 generic. cn



My conclusion: MH is much superior for veg. cn

It's worth it. The spectrum of the mh imitates spring and erly summer. You will see it as a blueish white. While hps is more red. Late summer and fall. This works with the photo period of the plants. growth won't be that noticeable but when flowering stretch comes you will see how healthy the plants where. But you can use ether mh or hps the full grow. Me personally I have 2 1000s and a 600 in my flower room. So I switch lights like summer dose. First week of flower all mh. Next week or 2 hps in the 600. Then hps in the 2 1000's and mh in the 600. Last 3-4 weeks is all hps. I'm to cheap to get dual spectrum bulbs. I just switch.

a few years ago i always read to veg with a mh and flower with hps. several grows i did exactly that with a 400 watt in a 5x5 tent. awesome results by the way. i ended up upgrading to a 600 watt system. only had a 600w hps. i am able to dim my ballast to save on the electric bill and/or reduce heat. i turned it down to 400 for veg. from what i seen the hps did even better. i cant really say for sure because it wasnt like 2 grows done side by side so its hard to give it a real fair comparison because other variables like temps could have been different. ever since then i only veg with a hps though. it seemed faster and the leaves seemed to get bigger. nodes were even a bit tighter. mh does have a better spectrum for foliage. but the hps has more lumens per watt. imo i like hps better but would be cool to see someone do a side by side with identical conditions.

i have no choice with my perpetual 12/12 from a seed grow....damn it lol

i think im going to get a mh for veg, im only growing them to 12 inches before i induce flower due to the fact that i am in a dwc system that is 18 inches tall and i only have 6'5 from floor to roof. im growing 40 plants sog style so i dont have much room and i have 2 600w and a 400w, im even thinking of using the 400w mh that i veg with in the middle of the 2 600w i have with them pushing hps for a good spectrum of light for flowering. but im def getting that mh for vegging. thanks for the info and charts canna you have been a huge help from the start man. your great

You can veg under hps just fine especially if you are in dwc. the veg time is so short to get a 12 inch plant that you dont need to bother with a mh.

my friend you have been a good help within the past few minutes lol.

beer316 said:

a few years ago i always read to veg with a mh and flower with hps. several grows i did exactly that with a 400 watt in a 5x5 tent. awesome results by the way. i ended up upgrading to a 600 watt system. only had a 600w hps. i am able to dim my ballast to save on the electric bill and/or reduce heat. i turned it down to 400 for veg. from what i seen the hps did even better. i cant really say for sure because it wasnt like 2 grows done side by side so its hard to give it a real fair comparison because other variables like temps could have been different. ever since then i only veg with a hps though. it seemed faster and the leaves seemed to get bigger. nodes were even a bit tighter. mh does have a better spectrum for foliage. but the hps has more lumens per watt. imo i like hps better but would be cool to see someone do a side by side with identical conditions.

Click to expand...

My experience, as well (veg only), although I've run side-by-side, same everything, blah, blah, blah. I still try MHs on occasion, like last season when I tested a pair of Digilux 600MHs and saw the absolute slowest growth, ever, with HIDs. Frankly, Sylvania 400MHs were actually a bit better, but still no comparison.

Simon

Like you said 2 600w hps and 400w mh in the middle that would produce some killer bud with quality genetics.Good resin build up
in the plants under the mh for sure.

heres my first grow with a 400w mh in veg. 400w hps for flower. http://skiweeds.angelfire.com/ i like my hps better for veg now though. although now i use lumitek digital ballasts and bulbs.

dont matter these day there are new bulbs out now so you can get a [h=3]Sunmaster 400 Watt Warm Deluxe M.H. Bulb[/h] for mh and you can have the opposite for hps a cool bulb i think

MH for veg. Did a test few yrs back MH v HPS in flower and the MH did better with tric.production.Alot more frosty than HPS.