How close can a 400w hps be placed?

[Chicago-toker]

I recently have purchased a 400w hps light. It arrived in the 6th week of my NL flowering. I kept it about 20-24" from the plant. It did help for the final 3 weeks but was wondering if it is too strong to put closer. Going to start a holiday grow and want to get the most from my light. Thought I would check with other city dwellers on their distance with an hps. Thanks for the input.

Peace to the city............

[greenmonster714]

Hi chicagoT, I too have a 4 banger. Two as a matter fact....lol. My lamps are set in a perminate possition on my box. I grow with the scrog technique always so my screens is set at 20 inches from the lamp. It has always given me great results. I'd say your okay. gm714

[arouraindica]

i would say you want it as close as possible without heat becoming an issue.

i sused to run my 250W at around 5inches away, now its at about 8-10. The leaves grew bigger, the plant grew faster and the strethch was less when it was closer. (although im now on a 18vege rather than a 24hrs before)

[Stylez1877]

i'd say 18 inches is about as low as you want to go.

[chamez]

ive always heard anywhere between 16 and 20 for a 400 watt

[buzb8lvr]

With a fan blowing on it I can easily get within a foot. Unless you need a larger light footprint, I would keep it as close as possible without causing heat stress.

[Fugerty]

The secret to growing is to get the light as close as possible to the plants without burning them. A 1000 HPS badly positioned may only give the same LUMENS as a 400 HPS which is well positioned.

The closer you can get the 400 HPS to the plants the faster your plants will grow. There is no guide in inches to how close you can put your lamp as this has got to do with what type of REFLECTOR you have and if you have a Heat Shield in place. Some cheaper reflectors will get hot spots as the heat will not be disperced correctly. Get a good reflector and heat shield and your yields will speak for themselves. The SUPER HOVA or ADJUSTAWING are great reflectors giving much more lumens to your plants.

To get the optimumn distance put the back of your hand on top of the plants and move the light towards the plants. When your hand starts to get hot, Stop and that is a close as you can move the lamp without burning the plants.

[Rumpleforeskin]

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