I am a rookie, but I bought a ballast and 1000w hps at an electrical supply house (for electricians), I paid 125 for the ballast and 30 for the bulb, had to do the wiring myself. I grow lettuce and tomatoes indoor, have many problems b/c I am a rookie, but they grow like mad and set fruit under that light. My experience has been great with the light. I'll send you pics and how to's for the wiring if you want. Note, I don't think home depot carries what you want.

Thanks. They have the bulbs, but not the ballasts, Around $25-30 for 400W metal halide or HPS

The initial lumens and lumen maintenance on the MH bulbs from Home Depot is quite bad. These bulbs are often universal burn which doesn't help either.

Look into pulse start metal halide. You can order a bulb online for about $30. You can order a pulse start ballast kit for about $55.

Google "pulse start metal halide" or "pulse strike metal halide" for more info.

Regards,

Rokal

Lumens are not what you care about when growing plants. Lumens are based on a scale that's exactly the opposite of what plants are interested in. The lumen scale weighs green extra high and counts red and blue very little. Plants do little with green light but are very efficient with red and blue light. For example, low-pressure sodium bulbs are the highest luminous efficiency bulbs available. But grow plants with them and they'll end up chlorotic; it's all yellow-orange light.

In general: if you want your plants to leaf up, go for the highest kelvin temperature you can. If you want them to fruit, go for the lowest kelvin temperature you can. If you use HID/MH/HPS, invest in an electronic ballast; it's well worth it. CFLs aren't quite as efficient as HIDs, but they do work if you get enough of them, as powerful sa you can. Lower up-front costs, certainly.

I'm not sure if there's much difference in the bulbs between the two. I'd say the plants probably don't care much either, but that's just my guess.

I'm actually kind of surprised that lermer hasn't found this thread yet. He lives for the opportunity to say "ceramic metal halide"...

Im currently using a standard sylvania 400w mh from the home depot. no noteworthy decrease in performance from the pricey eye bulb it replaced (due to budget, of course )

They work fine how do you think people found out that hps worked so well to grow plants buy using the orginnal ones from home depot Ive grown with a hortlox side by side with a off name brand from home depot and saw very little deffernce

You need to get a grow light 600w because it puts out more lums per watt then any other watt light. Even with a 600w hps system you will only get about 25 sqft of grow area so keep that in mind.

Well a 1000 watt will put out more lumens than a 600 watt light will, and a 1500 watt light will put out even more than that. I don't understand why you would recommend (say "You need to get") a 600 watt over a 400 watt when there is no mention of the type of plants being grown, nor any mention of the square feet of grow area. At least in the resent posts from this year, and not the ones from 2009.

1000watt= 150000 lumens at most. 150 lumens per watt
600=95000. 158.333 lumens per watt

Doesnt sound like much?

2 600w hps= 190000 lumens
1 1000w hps= 150000

for 200 more watts you gain 40000 lumens

Note: a 250w hps putts out 28500 lumens

Do the math.
O wow this post is old.

First there are can be vast differences between manufactures, so those numbers might be right from one manufactures, that doesn't mean they are even close for another. Second even if someone winds up getting bulbs that match those figures, that doesn't mean that a 600 watt bulb, or multiple 600 watt bulbs are the best choice for every situation. Other considerations include heat buildup, electrical costs to run the wattage, equipment costs (especial the ballast), the actual amount of space and plants being grown, the type of plants and the light requirements of the plant etc. etc. etc..

So to simply say that a 600 watt bulb is the best value, and bulb to get for every situation is a bit off. Even if every bulb manufacturer had the same specs on their bulbs as all the rest of the manufactures in the planet (witch simply isn't the case).

Those extra 200 watts equal 1/3 more electrical cost as well, not to mention the added electrical cost for more ventilation because there will be 1/3 more heat from it also. If the extra wattage isn't needed, that's wasted money, as well as wasted lumens in my eyes.

Fact is a 1000w system is as much as a 600w system up front cost. 600w cost that much for a reason.

10-600w hps= 950000 lumens and 6000 watts
6-1000w hps= 900000 lumens and 6000 watts

Not that much but still substantial.

I am just stating that 600w lights save on power. A 1000w is an american thing lol (less upfront cost). Go look into europe and see what they use it is mostly 600w for a reason it saves power. more lums per watt.
Look at 2-1000w vs 3-600.
3-600w@1800watts=285000 lums
2-1000w@2000watts=300000 lums

Now that I look at that. It is not much considering you to buy all those 600w hps systems.