Lower wattage than ballast and lumens per sq ft

Hey yall,

Thinking of getting a better grow light (currently got less than enough) and saw a very good price on a 600W HPS, thing is my grow area is about 55x50 cm sq, which is small. So could I put a, say, 250w bulb on the 600w ballast, and have it work safely. If not, would 600w be overkill?

Did some quick searching and answered my first question, which to those wondering is a no, it would not work and may not be safe.

Lol............."may not be safe" is a bit of an understatement - you should never mix and match wattage of HIDs.

And the old rule of thumb is that as long as you can keep the temps in check, there's no such thing as "overkill" with regards to lumens.

That being said, 600W on ~3.5 sq. feet is as close to overkill as I've heard of.

Split the difference and get a 400 with an air-cooled hood and you should be golden.

Bob Smith said:

Lol............."may not be safe" is a bit of an understatement - you should never mix and match wattage of HIDs.

And the old rule of thumb is that as long as you can keep the temps in check, there's no such thing as "overkill" with regards to lumens.

That being said, 600W on ~3.5 sq. feet is as close to overkill as I've heard of.

Split the difference and get a 400 with an air-cooled hood and you should be golden.

Click to expand...

600watts in 3x3 is not overkill if its cooled, i run a 1000w in a 5x5 room. thats 140,000 lumens for 10~ plants, 14000lumens/plant....... thats over kill.....

but seeing as a 600w puts out around 90,000 lumens over a 3x3 area, id way 6-8 plants your still breaking the 10,000 lumens/plant ratio needed for maximum flowering potential.

Thanks for the help, only reason I was looking at such a high wattage was because I saw one really rather cheap on eBay. I think a 250watt would be best.
Is there anything wrong with using low bay lights, rather than a proper grow light thing? I mean they use the same bulbs and all, only problem I see is that the ballast is built in, which increases heat, but I've got pretty good ventilation, and it can't be too hard to separate them *touch wood*. Thanks again.

Just to note 3x3 is 9 sq feet he only has aboput 3 sq feet of room. For 3 sq feet i think even a 250 would give great results and can get by with a 150. That said, there is not much difference in the price from 250 to 400 so i would go with the biggest you can cool just so you have room to expand if you ever decide to.