400w CMH vs. 1000w MH

[partcleguy]

Hey guys, I'm finally finishing up a new tent set-up, a GL120 basically 4'X4'X6', and I have a magnum xxxL 6" hood and 1000w switchable ballast/bulb ready for flowering. I plan on using a 400w CMH to flower under, but with the size of the grow-space, it doesn't seem like enough light. I plan on germinating about 10 seeds to cull down to 4 nice ladies so I will have to fit about 9-10 plants under the hood during veg.

Would it be better to start with the 400w CMH and then switch to a 1000w MH in the last week of veg/first week of flower, or to stay with the 400w CMH and hang a few 23w CFLs around the outside?

As an alternative, I could probably bolt another socket on an L-bracket and run the wires through the ducting so I could add a second 400w CHM, but I don't really wanna buy another 400w ballast if I don't have to...

BTW, if I went with the 1000w MH I would probably lean towards getting a cheap bulb unless that makes all the difference...

 

[B. Friendly]

if you're willing to spend some dow on cooling then you can do it. But know a 1000watt MH is good for vegging but get a switchable digital ballast so you can run HPS for flower.

anyways the cheapest cooling system is abut $250. Get a garbage can, submersible pump(you'll need a on/off float if you don't remember to fill your tank), and this cheap chiller:
http://www.amazon.com/gp/product/B002B91QBA/ref=oss_product

 

[partcleguy]

Thanks for the feedback, but I forgot to mention I'm going to be running hand-watered coco so no need to worry about rez temps.

I have a switchable ballast so I have the option of MH/HPS, I am def. going to do HPS in flowering.

So I'm still wondering are MH bulbs/spectrum so inferior to CMH bulbs that it would be better to just stick with a 400w CMH throughout all of veg or to switch to a 1000w MH in the last week of veg/first week of flowering??

 

[cyat]

I've used all three. Cmh imho are no better than anything else. They run just as hot as any other 400. I would never use cmh again. I prefer 1k hps overall , but mh are just as good if not better than cmh. cmh are very over hyped.The same guy who promotes them is the same guy who sells them. That's a biased forum. I bought 14 from the guy , took forever to get them, and they came weeks apart.Mogul sockets were damaged and cheap , which he never replaced. pita too , and so many cords.

 

[partcleguy]

Ok, so that's one vote for just switching to a 1000w HPS or MH during the last week of veg.

Anyone else? I would think that although CMH bulbs are supposed to have a better spectrum/PAR output (I use the Phillips retrofit CMH bulbs), just the sheer wattage and output from a 1000w MH would provide enough PAR wattage to do better than a 400w CMH right? Plus just a better footprint...

Anyone else?

 

[partcleguy]

Bump

 

[Bob Jones]

I'm running 2x 400w CMH in my veg area which is about the size you're talking about. They're both mounted in one large size Adjust-A-Wing reflector at opposite ends. It works great, the plants really do well and it's about the right amount of light for the area. One 400w would definitely not be enough.

Either use two of the 400's or go with a 1000.

 

[FoCo(No.Co)]

I've used all three. Cmh imho are no better than anything else. They run just as hot as any other 400. I would never use cmh again. I prefer 1k hps overall , but mh are just as good if not better than cmh. cmh are very over hyped.The same guy who promotes them is the same guy who sells them. That's a biased forum. I bought 14 from the guy , took forever to get them, and they came weeks apart.Mogul sockets were damaged and cheap , which he never replaced. pita too , and so many cords.

I love love love my 400W CMH. I'm thinking you must have picked a bad source and ended up with less than optimal equipment.

After experimenting with CMH for a few months, I gotta say, I will never buy any other kind of light again...

Ok, so that's one vote for just switching to a 1000w HPS or MH during the last week of veg.

Anyone else? I would think that although CMH bulbs are supposed to have a better spectrum/PAR output (I use the Phillips retrofit CMH bulbs), just the sheer wattage and output from a 1000w MH would provide enough PAR wattage to do better than a 400w CMH right? Plus just a better footprint...

Anyone else?

When picking lights, Watts per Square foot(W/ft.^2) is what you want to consider. During veg, 15-25 W/ft.^2 of HID light is perfectly adequate. During flower(which requires more energy), 40-75 W/ft.^2 is ideal under normal conditions.

With your 400W CMH, you will be at 400W/16ft.^2=25 W/ft.^2, which is at the high end of ideal for veg

With the 1000W MH, you will be at 1000W/16ft.^2=62.5 W/ft.^2, which is in the high end of perfect for flower.

IMO, buying a HPS bulb for your 1000W ballast will not be worth the increase in lumens becuase you are already in the high end of the ideal power range for the size of your canopy. Also, I swear MH bulbs produce more colorful, fragrant and resinous flowers.

 

[FoCo(No.Co)]

One 400w would definitely not be enough.

A 400W CMH will most definately produce dense vegitative growth in a 16 square foot space...

These plants were vegged under one 400W CMH in a 24 square foot space-

 

[partcleguy]

Wow! Thank you so much- that's the kind of feedback I was hoping for! I already have several 1000w HPS (Hortilux Super HPS) bulbs so I plan on using those and I'll probably just keep some blue spectrum CFLs in the cab for at least a little balanced spectrum.

 

[scurred]

I got my CMH from a industrial lighting company in my state. Nothing was wrong with it. Not sure on the results though, because I havn't used it.

 

[FoCo(No.Co)]

Wow! Thank you so much- that's the kind of feedback I was hoping for! I already have several 1000w HPS (Hortilux Super HPS) bulbs so I plan on using those and I'll probably just keep some blue spectrum CFLs in the cab for at least a little balanced spectrum.

Oh I see, I didnt understand that you already had an HPS bulb.

Here is the spectrum for the super HPS, as you can see there is already quite a lot of blue light produced by that bulb. You will probably just barely be able to keep the 1000W lamp cool enough anyway and adding CFLs just isnt worth bothering, in my humble opinion that is.

Good luck with the grow duder.