Hi Guys, Always been interested about how HPS and MH lighting affects the vegetative stage of marijuana growth, so I decided to test it. In the first two photos, the seedlings are under a Dual Spectrum 600w HPS omega light, and in the second two photos the seedlings are under a 600w Metal Halide Omega bulb. Each photo is day 5 and day 11 after sprouting respectively. It is fascinating to see the difference in growth rates, as MH is widely considered the better option for veging. I personally in my own experience found that the seedlings under HPS grew at a much faster rate to begin with. However, the MH bulb although growing at a slower rate are producing much more compact, sturdier plants with much smaller internodal gaps. After using both I would probably continue to use Metal Halide bulbs in the future. Note: I have found that Omega bulbs seem to dim greatly after 6-8 weeks of use and no longer are as effective compared to Phillips bulbs for example. Anyone else found this issue too? Hope this info helps guys will continue to document process!
Interesting.... How high are your lights above the plants? Only asking as i use a dual spectrum HPS bulb from veg to harvest and i always have close internodal gaps...… Nice experiment though.
Hi Paolo, my lights are as close as I can ever get them without the plants being stressed at all I.e light burn and has been at same height for both grows, but of course I close the gap as the plants get a little older and can withstand more light. Thanks appreciate it I would say the differences noted are quite small though, so personal preferences probably prevail here
Update - the two photos are on day 15 of veging with each Grow. Yellowish light dual HPS and white light MH. I really can't understand how people are claiming MH is better now. Look at the size difference with the HPS bulb. Thinking I might change the MH to Dual HPS now... thoughts??
Thought this might happen & yes i would bro...! Proof is in the pudding. At this age though, i run my HPS @ 400w....Good work mate