I'm not saying i agree or disagree but i can confidently say i'm more confused about lighting now and am uncertain as to what to recommend.First Question:
I purchased a 400-watt metal halide (MH) lamp. The salesman told me that the lamp could be used for both vegetative and flowering. However, a fellow grower told me that the MH would be a waste of time and a high pressure sodium (HPS) lamp should be used instead. What do you think?
Second Question:
In a single-light garden is it better to use an enhanced spectrum HPS lamp such as a Son Agro 430-watt bulb as opposed to a regular HPS to emit more light in the blue spectrum?
Eds Response: (emphasis mine):
MH lamps contain more blue light and less red light than HPS. HPS lamps produce more total light than MH lamps and more light in the red spectrum, which is used more efficiently than blue light, powering a faster rate of photosynthesis. In addition, read light helps in flowering development.
The only reason to use an MH lamp rather than an HPS is to avoid suspicion that a weird-colored light may arouse. Using metal halide lamps in any stage of growing is a waste of time and money. More total light that is useable by the plant is produced by HPS than MH lamps, so plants grow faster using HPS lamps alone.
The plants dont need the extra blue light offered by the Son Agro. Enhanced blue light doesnt increase production. Although plants use blue light for photosynthesis, they use more red light. In rooms with mixed lights (MH and HPS), the plants between the two lights, which were receiving a mixture didnt perform quite as well as the plants directly under the HPS lamps, but yielded slightly more than those under the MH. You could see the wave effect.
The solution to the ballast problem is to replace the MH bulb with an MH-to-HPS conversion lamp. This bulb will fit into your system and is powered by the same ballast as an MH but it emits an HPS spectrum.
seemorebuds (Garden_Knowm) did ask Ed about this for clarification but hasn't yet received a reply.Yeah, confused indeed. I hear good comendable things about this ed so im assuming he knows his shit. Thats a pretty crazy statment. Hes saying there really is no place for mh? That its all bull shit, all they need is an hps for optimal growth? Shit i thought blue cfls might be doing my plants better good thatn my 150w hps for vegg, but i think now im going to switch it around.
Plus rep on that info+++
Notwithstanding the comments on whether MH works best for veg or not (the general consensus I've seen... books/internet... seems to be that it does), I just finished veg growth for my white widows using an MH conversion bulb (400W) in an HPS ballast and the lighting system worked just fine. I switched in the HPS bulb 3 days ago to start 12/12. Don't know how the growth compared to if I'd used HPS only, but my plants were 15" tall after 29 days from sprouting and very bushy. In any case, for your initial question, I had no problems using an MH conversion bulb in the system.Im thinking of buying a MH conversion bulb for my HPS ballast. Anyone else running one of these? Are they any good or is it worth buying a MH ballast?
Ed was pretty clear which is why i thought it worth a look. He has more experience growing than most of us put together so i don't dismiss his opinions so easily.I Completely disagree with Ed's statement. It is considered common knowledge that MH spectrum is superior for veg growth while the more efficient HPS is more effective for flowering.
It is true that MH produce more heat and less lums but that doesn't mean the spectrum is not preferred by the plants. In veg growth you generally have plants taking a smaller footprint anyway so the transition form your say 400 MH to 400 HPS simply means you move the light further away. I assume ED made a mistake or forgot to mention something. Genetic laboratories focusing on botany always suppliment MH spectrum for vegetative growth and HPS for flowering.
Read everything else on the internet and you'll see it's common knowledge a transition from MH to HPS for flowering is superior and has been well documented. I'm a new member here but I've been in this for a long time I I can say with certainty,
MH=Veg, HPS=Flower