600watt for veg 1000watt for flower

I've been using a 600 watt HPS from start to finish with my last few grows. I've decided to upgrade to a 1000 watt HPS.

In the interest of cutting power costs, i want to do future veg cycles under the 600 watt and then use the 1000 watt for the flower cycle (given that during veg, the lights are on 6 extra hours a day).

I've worked out that it will cost roughly $57 a month to keep a 600watt going 18 hours a day, and $95 a month to run the 1000watt 18 hours a day. Thats a pretty significant difference and unless i will be gaining some decent advantage from vegging using the 1000watt then i might aswell just use the 600 and save the 1000watt for flower only.

So, will there be any real advantage with the bigger light during veg only?

I would love to know this as well as I'm using a 400 watt for veg and plan on using the 1000 for flower.

Anyone have any advice?

i would love to see an experiment done to answer the latter questions...I usually veg under cfl's and then switch to 400 watt hps for flowering

That's right, the 600 watt HPS is the most efficient of all HPS lights - regardless of wattage. I'd suggest, if you can fit, adding another 600 watt. Regardless, look for increased heat - lots of it!

Increased heat is something not all of us can or want to have to deal with...

I know 2 x 600watt lights is better than a single 1000 watt, but i'm talking about single light setups only here.

I know this is an old post and sure you got it figured out by now. I have a 10x10x7 tent and 4-1000 HPS, I vegged on 600 watts each light and 1000 each on flowering and the wattage is to much and the leaves turn down, sideways and some even flip over trying to get away from the excessive light. I turned them back to 600 each totaling 2,400 watts and they have never been happier. However, if I had bought the extension for the top of the tent I think the 4,000 watt total would have been good maybe another 2 or 3 feet higher. I never lowered the lights and let them grow to the lights and they never got stretched out and in fact were very bushy and tall. The strains I grew was White Widow, Power Kush, Grand Daddy Purple, G13 Cheese and Liberty Haze. I will never mess with Liberty Haze because all things equal in my Hydro set up they are spindly and sickly looking and finished out fair so they have been added to the drop list.

I believe less is more because most of the plants I burned with too much light will never totally never recover 100%.