400 Watt HPS or Metal Halide - Which is better? How many plants?

I have 2 lights in my grow room. I have 2 400 watt High pressure sodium bulbs as well as 2 400 watt metal halide bulbs.

On my current grow, I ran the metal halide lights at 18/4 for vegging. Now i have the HPS in and am running 12/12 for flowering.

I've heard you can do an entire grow with either one of the bulbs, just change the on/off hours. Is this true? If so, which one works better?

Last question, how many plants, as a general rule of thumb, should I be able to grow under these two lights?

Really you could grow with both. But most ppl will tell you that the way your doing it is better. Plus you already have it so
I would.

as many plants as you can fit in a 3x3x5 area, and both bulbs (hps and mh) on 12/12 and 18/6 full spectrum better for the plant better yields and quality.

you can do an entire grow with either bulb but the way the plant will grow is very different also depends on how close you have the light the closer the better in most cases.


when i was using a different setup than my current one i was using 400w MH and 400w HPS on 12/12 in a perpetual setup as plants went in the started under the MH then as they age moved their way over to the HPS until they where cut. this helped me keep them short and bushy reducing on flowering stretch.

right now im kinda doin a vert setup so im using my HPS stretch to my advantage.

hps for flowerMH for vegend of story