250W or 400W HPS light

Stuck on a light/growspace/plants problem.

Right now I have 6 plants and growspace ~1,5m2 = 50sqfeet.

And I need help for light. Which to choose:

1) 250W HPS TS, 35000 lumens, growing area 0,9m2

or

2) 400W HPS TS, 60000 lumens, growing area 1,2m2

Could I grow good yield with 250W in my growspace or I need 400W light? Will use light with reflector!

Thanks a lot for your help,

Mari.

Just get the 400 you will be happy.

Well I have been having the same problem lately. Trying to set up my veg box. However I read a few different sources that say 250w run about the same temp as 400w (with in 5 deg of each other) I would say if you have heat problems go for the 250w but if heat is not your biggest problem go for a 400w in a 6"cool tube running at least a 265cfm fan and that would be great for your area. or possibly a 250w with a light mover and a ScrOG set up. That might be the shit

JollyGreen420 said:

Well I have been having the same problem lately. Trying to set up my veg box. However I read a few different sources that say 250w run about the same temp as 400w (with in 5 deg of each other) I would say if you have heat problems go for the 250w but if heat is not your biggest problem go for a 400w in a 6"cool tube running at least a 265cfm fan and that would be great for your area. or possibly a 250w with a light mover and a ScrOG set up. That might be the shit

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50sq ft get a 400w. im running one in my closet. make sure make sure make sure you VENT properly. For best result have fresh air blowing in from an exhaust fan (best result when hooked up to your reflector) and one high cfm (170-200cfm) fan sucking the air out and letting it out of the room or better yet hooked up to the duct work of ur house or apt. Your plants and light need fresh air coming in and hot air and smell going out. Anyways best of luck

400w. Period.

Thanks for help,

Then I will choose 400W HPS light!

I will use with this reflector:


One hot air out vent 365m3/h with termostat:



1) Fresh air in, what kind of vent I could use? I'm thinking to use 2 x PC vents (44.71 CFM; size 12cmx12cm), would that be enough?


Thanks a lot for your help,

Mari.

You would probably be better off with an active intake because those CPU fans will bring in less air than the inline fan you would be using. I use a 300+ CFM fan with a 4 inch passive intake and the temps are great

What are the dimensions of the room? 1.5 square metres or 1.5m on each side? Neither way equates to 50sq ft, I'm just wondering where you got this figure from.
If it is 50sq ft, then a single 400w is nowhere near enough. Optimum light levels are 7-10,000 lumens per sq ft, so you are looking between 6-9sq ft. Plants will grow with 3000 lumens/sq ft but you'll be much more impressed if you can give them more.

I was debating between the 250w HPS and 400w HPS Grow System too. I'm also growing 6 plants and the size of my grow space (a closet) is very simiiar to yours. In the end, I chose the 400w HPS System because I wanted my plants to get enough light.

It's been almost a week with the new lights...and I totally agree with switchone. Having a proper exhaust system is vital. Even if its just a fan blowing the air out of the grow space. I'm cheating a little bit, cuz I've been using my 12,000 BTU A/C unit to cool my entire room. Withouut the exhaust fan or A/C unit, my temps would definitely be in the 90's. But with the A/C (10-12 degree impact) and the exhaust fan (2-5 degree impact), my temps are 74-80. Obviously, my electricity bill will be a bit more running a 1280w A/C unit...but I tried a proper exhuast system that ran out from my air cooled reflector and I couldn't get the same results when compared to my A/C unit.

Hey, thanks for your help!

Will go for 400W light, hope the plants will grow like crazy with it.

the max yield you can get with a 400 watt is 400 grams which is a little less than a pound i always go with 600 or 1000 watts

sa1asjok3r said:

the max yield you can get with a 400 watt is 400 grams which is a little less than a pound i always go with 600 or 1000 watts

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the max yield? thats just a rough figure for people to reach. Its very possible to get 500 gram, not easy, but its more likely that someone recieves only 300 gramms. all about the genetics and the green thumb.

That sounds wrong if 400w = 400g, or it's for one plant?

But you can push up to >600g in m2.

One last question about grow space,
I will grow 10 plants (The Church and The Doctor) and with my grow space (1525x1525x1525cm) will be enough? I hope that tight space won't effect yield.

Thanks for your help,

Mari.

The 400w = 400g is based on the assumption that a good grower can get 1g/w out of a grow, but this is by no means a maximum, and is not necessarily achievable, depending on the strain..
I assume those measurements were in mm, which would give roughly 25sq ft, more than enough space to grow 10 plants. A 400w will cover an area between 2.5x2.5' to 3x3', and you might just squeeze 10 plants in there, but you will need to flower quite early to stop them getting too big and shading each other.
The space won't affect the yield, it's the amount of light you put in there. General consensus is that a 1000w will cover a 4x4' primary growing area, with an extra foot around the edge of secondary lighting.
I would suggest getting the biggest light you can afford to run and keep cool. I have a similar sized space as my flower room, but I only grow in a 3x3 area under a 600w, with 6-8 plants at a time doing a perpetual grow. I usually get 40-50g per plant, and harvest 2 every fortnight.

One last question, could you post the right temperature and the right humidity, which I need for growing.

Temps should be between 75-80 degrees..............


Or just look in the FAQ: https://www.rollitup.org/view.php?pg=faq&cmd=article&id=582

Hairy Bob said:

https://www.rollitup.org/view.php?pg=faq&cmd=article&id=582

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Hey, thanks for the link!