GreauxFast
Active Member
In my second week of flower, starting to stretch a bit. Canopy is even at the top. Any suggestions on distance from light with aluminum diffuser?
400 Watt HPS distance
- Thread starter GreauxFast
- Start date
Markshomegrown
Well-Known Member
You need to keep the hood 10"-12" above the canopy. (if the bulb is horizontal)
Markshomegrown
Well-Known Member
I have used air-cooled hood too, you don't want a 400w HPS any closer than 10"It's going to depend on the heat. An air cooled hood makes a big difference.
GreauxFast
Active Member
I’m good there, walk in closet well ventilated, 80-85 high and 73’s lowsIt's going to depend on the heat. An air cooled hood makes a big difference.
Markshomegrown
Well-Known Member
Have you lot used a lux meter? and seen the drop-off at 14" and the lux at 8" from a 400w HPS in a horizontal reflector?
you don't want the lux less than 40k or more than 80k
( just added) I have seen that chart on the net for the last 10 years, I think the lux is from a vertical 600w, magnetic ballast
you don't want the lux less than 40k or more than 80k
( just added) I have seen that chart on the net for the last 10 years, I think the lux is from a vertical 600w, magnetic ballast
Last edited:
Midwestsmoker419
Well-Known Member
I have run 600w inches from the tops.
Markshomegrown
Well-Known Member
I used to do this, yes I pulled a crop but It took years for me to realize the damage I was doing to the plants, bleach leaves, white buds, edges of the fan leaves turning up, purple stems, the plants were stressed and I didn't know why, though it was everything but the light.
Now I know.
hotrodharley
Well-Known Member
Those temperatures are fine for LED. Not so much with HPS.
vostok
Well-Known Member
distance from plant depends much on your local air temp for that
I like to leave a temp gauge at top most leaf height and raise or lower accordingly
leave it sit for 15-30mins aim for 77f -25c tho I like 30c
good luck
Markshomegrown
Well-Known Member
So in the winter, you would keep the hood 10" above the plants and in summer you would keep the hood 20" above the plants?
If this keeps the canopy temps in range
Midwestsmoker419
Well-Known Member
I have only had leaves start to show signs of bleaching. I then checked with a meter and raised slightly until there was no more bleaching. Some strains can handle more intense light then others.
Markshomegrown
Well-Known Member
You're right "Some strains can handle more intense light then others" the plants have developed ways to protect themselves from the extra light, they use more water and food to achieve this, just because the plant can handle the extra light without any bleaching doesn't mean they will benefit from the extra light, my flower room like most the other flower rooms on here are not going to be perfect and we all make lots of mistakes while vegging and flowering the plants off, if we give the plants just enough food, light and water at the right time, the plants will look more healthy and this will result in higher crop sizes for the average grower.
calvin.m16
Well-Known Member
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Markshomegrown
Well-Known Member
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and checked the amount of lux the plants are receiving, with a 600w hps, 19" above the canopy, my plants are receiving between 40k to 55k (new bulb)that's about 500 - 750umol/s/m2
Adjust-a-wing-reflector (middle setting), I can dim my lights down to 400w and check the lux, I guess it's around 15-20k(259 umol/s/m2).
Star Dog
Well-Known Member
For getting the bulb/reflector close a parabolic reflector is great but there's a light spread penalty being closer with either orientation, horizontal bulbs throw the heat down, vertical bulbs throw heat out more horizontally.
Of course it's hot but not skin removing hot.
660w hps
As mentioned above your ambient temperature plays a part in how close you can get the fitting, I used a thermometer in the canopy then moved on to using the back of my hand, 28/29c is ok if the ambient temp is around 25c... I've found.
Of course it's hot but not skin removing hot.
660w hps
As mentioned above your ambient temperature plays a part in how close you can get the fitting, I used a thermometer in the canopy then moved on to using the back of my hand, 28/29c is ok if the ambient temp is around 25c... I've found.
Markshomegrown
Well-Known Member
I have been tempted to get one of them, all of the light reflected from the hood back down to the canopy, could keep a 1k HPS(vertical) 12" above the canopy.