Is a 400 watt light enough?

C

ChicagoReaper

Hey guys,

First crack at growing super hots. Was wondering if a 400 watt light will be enough? It's less than a 4x4' grow area. Doing 4-6 plants depending on space.

Also read that pepper plants don't care if it's HPS or MH... Is this true? If so I am going to use MH to reduce heat. Right now I'm using a 600 watt HPS and it's way too warm.
 
I used a 400 watt HPS this season for seedlings in a 4x4 area. They shot up. Are you talking about full time under the lights for your plants, or just until they go outside?

I had no heat issues. If I'm not mistaken, MH runs hotter than HPS. You'll find it's debatable whether one type of bulb is better than the other. The guy at my local hydro shop said it's really splitting hairs, i.e., little to no difference for peppers.
 
A guy grew this with a 400w hps:
Even though it's outside at the moment, it was only recently transferred and grew that big in a tent with another plant to boot.
 
I don't have pepper experience with 400w hps but I do have experience growing many other things indoors with a 400w hps such as citrus, tomatoes, cucumbers, strawberries etc and I'm pretty certain peppers will do great under that light.. Just watch the heat(inline fan will fix the heat issue) and distance from the tops of the plants and you will be good..
 
I have an inline fan. I read somewhere that pepper plants don't care if it's MH or HPS because they don't have a definite flowering or veg stage.

Is this true? I would op for MH if that's the case. Less heat
 
I was always under the impression that MH ran hotter than HPS...anyways one thing I learned recently is MH bulbs actually increase the nutrient uptake of the plants under them, so if you go for MH make sure you keep up a good fert regimen.  I'm pretty sure you are correct when you say that pepper plants don't have a definite vegetative or flowering stage, but I do know that the type of light you use will help influence the plant under it (i.e. plants under a HPS are going to produce more than those under a MH bulb).  I used a 250w HPS to OW some plants and that kept them producing all winter, when it came time to start seedlings I switched over to a 250w MH and it seemed to work just fine if not almost too well.  I'm not sure if it's because I started seeds a bit early this year or if it was caused by the MH, but the seedlings grew up so fast that I had to pot them out early because they had used up all the nutes in the 3" containers they were in.  This year I have both a 250w and 600w system at my disposal both HPS and MH so I'll experiment and see if the effects increase using 600w.
 
Just my 2 cents
 
400 will be fine for that space, but you are better off working on a cooling system with your money and continue to use the 600.  They run about the same temp watt for watt(MH vs HPS)  and 600 is 50% more light, your plants will appreciate that.
 
 
sreinhard88 said:
I was always under the impression that MH ran hotter than HPS...anyways one thing I learned recently is MH bulbs actually increase the nutrient uptake of the plants under them, so if you go for MH make sure you keep up a good fert regimen.
 
Not really true.  The plant growth habit is the only thing that is changed with the different lights.  Nutrient uptake remains the same based on the same amount of plant mass.
 
 I'm pretty sure you are correct when you say that pepper plants don't have a definite vegetative or flowering stage, but I do know that the type of light you use will help influence the plant under it (i.e. plants under a HPS are going to produce more than those under a MH bulb).  
 
HPS will not produce more than MH.  They will produce the same given the same conditions and light outputs..  A CFL grow or fluro tubes will do the same as well.  Now the big difference with this is HPS produce more usable light than MH for the same wattage.  It is negligible but the difference is still there.  
 
I used a 250w HPS to OW some plants and that kept them producing all winter, when it came time to start seedlings I switched over to a 250w MH and it seemed to work just fine if not almost too well.  I'm not sure if it's because I started seeds a bit early this year or if it was caused by the MH, but the seedlings grew up so fast that I had to pot them out early because they had used up all the nutes in the 3" containers they were in.  This year I have both a 250w and 600w system at my disposal both HPS and MH so I'll experiment and see if the effects increase using 600w.
 
Just my 2 cents
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There is far more to get into with this topic but all the answers are out there in this forum.  Another HUGE thing to remember is nearly all of the available "grow" lights are directed at one single crop and chilies are not that crop.  The habits of both plants are entirely different and regimens should be as well.
 
MH definitely burn cooler... I've been an indoor grower for 6 years. HPS is quite a bit warmer watt to watt.
Grow lights are definitely not geared for one specific plant or there would be a million different types of lights. It's all about spectrum! What does this certain plant like in the spectrum?

I've read that peppers don't have a definitely flower cycle, so my guess is mh will promote veg growth and HPS will promote flower development. Or would that just be with the light timing?
 
ChicagoReaper said:
I have an inline fan. I read somewhere that pepper plants don't care if it's MH or HPS because they don't have a definite flowering or veg stage.

Is this true? I would op for MH if that's the case. Less heat
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SichuaneseFoodFan said:
where do you see MH makes less heat than HPS?
 
thanks
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MH runs cooler. Trust us.
 
ChicagoReaper said:
MH definitely burn cooler... I've been an indoor grower for 6 years. HPS is quite a bit warmer watt to watt.
Grow lights are definitely not geared for one specific plant or there would be a million different types of lights. It's all about spectrum! What does this certain plant like in the spectrum?

I've read that peppers don't have a definitely flower cycle, so my guess is mh will promote veg growth and HPS will promote flower development. Or would that just be with the light timing?
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Run the MH. If for nothing else, your eyes will appreciate it. At around 40,000 lumens, you will have plenty of light for 16 sq.ft. HPS will give you more lumens, but you don't need them, and the red light is annoying. The pepper plants will both grow and bloom under the MH light. Look at the winter part of my glog this year. I run a 600 watt litght in a slightly larger space.
http://thehotpepper.com/topic/43217-jeff-hs-2014-glog-pube-pods-are-forming-hoot/?p=928649

plenty of light.
 
MH does not run cooler.  They are less efficient than HPS.  HPS convert more electricity to light energy therefore less heat.  MH convert less electricity to light energy therefore more heat.  It really is simple physics.
 
MH run hotter.
 
millworkman said:
MH does not run cooler.  They are less efficient than HPS.  HPS convert more electricity to light energy therefore less heat.  MH convert less electricity to light energy therefore more heat.  It really is simple physics.
 
MH run hotter.
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I 100% agree with your logic, but  you are talking about waste heat. Nor irritated heat from the lights electromagnetic waves. My grow room was warmer with the HPS bulb in there. Hands down.
And yes, HPS is more efficient. Quite a bit more actually. In the case of my 600 watt system, they are like 30,000 lumens apart.
 
Maybe it has something to do with the wavelength of light it puts off. But if the HPS is putting off 30,000 more lumens (600 watt bulb), that is more red spectrum light that is heating up everything it shines on. Remember electromagnetic waves contain quite a bit more than visible light.
We're probably splitting hairs between the difference in the statements "MH runs hotter" vs. "MH heats up my grow room more"
 
Yes, MH is less efficient and generates more waste heat, but the grow room is still cooler overall.
 
millworkman said:
I was always under the impression that MH ran hotter than HPS...anyways one thing I learned recently is MH bulbs actually increase the nutrient uptake of the plants under them, so if you go for MH make sure you keep up a good fert regimen.
 
Not really true.  The plant growth habit is the only thing that is changed with the different lights.  Nutrient uptake remains the same based on the same amount of plant mass.
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I believe I was the one that gave him this impression. It was in regard to bumping up from CFL to MH IIRC, as with similar wattages the MH will penetrate the canopy further and increase growth.
 
Either  MH or HPS  Does not matter. The heat needs to be exhausted either way is the important thing. They're both hid and create massive amounts of heat compared to cfl.
 
millworkman said:
MH does not run cooler.  They are less efficient than HPS.  HPS convert more electricity to light energy therefore less heat.  MH convert less electricity to light energy therefore more heat.  It really is simple physics.
 
MH run hotter.
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Es verdad, HPS is more efficient than MH and runs cooler.
 
Ceramic Metal Halide bulbs definitely run a lot cooler than HPS.

and here are some quotes from cannabis sites...
 
 
I actually run both a 400W MH and a 400W HPS at the same time (side by side) and can confirm that the HPS runs noticably hotter.
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But in magnetic ballast, its pretty much been common knowledge for a very long time that HPS burn much hotter them MH-
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The main source of 'heat' from an HPS lamp (that effects grow room temps) is the amount of dark surface area that is absorbing the infra-red from the lamp and radiating it to the room as heat.

MH (in most spectrums) have much lower outputs of infra-red and don't experience this effect as much.
 
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