i was told for growing I should use Metal Halide, and for Flowering use The Hps.....Please correct me if im wrong.
i can't help to mention this.
i start off my grow from seeds with a 400w mh. i got mine to sprout in one day in a biodome from park seed with a heating pad with auto shut off from walmart and disstilled water.then after 1 week i add a 1000w hps and transplant to 10'' pot with soil,worm castings,h.phos.bat guano,lime in mirical grow potting soil with ferts and a good watering with general hydroponics micro, to get a good start.i did a couple varriations but found this to work the best. day 27 i transplanted to 25 gallon pots with mushroom compost and more of the same as above. they was root bound bad,so i would suggest transplanting sooner.so 400watts mh 1000hps.on day 28 i got some fine looking plants.the mh is alot hotter than the hps but adds blue light with a consistent 18/6 on/off light scedgual. i believe helped her be a girl.the electric bill might be a fuzz higher but with this kind of vigorous growth.my 8 miles high is 28 days from seed.13'' tall on her 11th node with pre flowers on her 8th and 9th node.now that extra 10 to 15 bucks on the light bill was worth it to me.i've got an afganica free bag seed that's like 6'' tall on it's 9th node with with like 3'' wide leaflets 4'' long growing right along side.oh and the 8 miles high has got a node on the second branch with 4 leaves and 3 branches growing from that one node.makes me have to get a camera.i never seen such growth in my life and i'm like as old as dirt i feel sometimes.so i'll keep this up,using both lamps at week 2 and on.it works for me.
that mh one hot sob but the mj likes it sho nuff.good luck with all your grows.
p.s.i'd stuff a 1,000,000,000 watt hps up in there if i could find one.where you would need a welding helmet to see'em when the lamp is on.of course it would spin the wheels right out of the meter through the neighbors windows but i'd still have that 400w mh goin just cuzz.peace grow on.