Need help - 600W HPS - Too bright?

I posted in the newbie forum yesterday, no response. Trying again here.
I have a 600W HPS in a sun system hood in a 4x4 tent over a scrog.
I had the lights 14" above the canopy during veg (MH) and flipped to flower and HPS and the center mass of the canopy started turning a lighter green.
I figured light burn so I backed off the lights to 18" and it seemed to continue so now I'm up to 20"

So now I'm just trying to figure out if I'm really looking at light burn or a nutrient problem. I don't want to pull the light so far back that it reduces yield.

Canopy-
This was two weeks ago when I first moved the light up to 18"

This is now



Some of the leaves have progressed from lightening to full on looking bleached.



The buds are looking nice now though, I'll be at 5 weeks tomorrow.

I’ve had HPS 400W at 40cm-45cm above canopy so I think you can put yours at 50-55 but from what I see at your last photos everything is good. Check temps at canopy lvl

Yeah, for about to start week 5 they do look just fine. Anyhow... what are they growing in, and what are you feeding them, and as for the light, is that a open hood, or a cooled closed hood, and what lamp are you using, brand name?

Ryuazki said:

I’ve had HPS 400W at 40cm-45cm above canopy so I think you can put yours at 50-55 but from what I see at your last photos everything is good. Check temps at canopy lvl

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Ok, so 14" is 35 cm - I was going on temps at the canopy level and not thinking of light intensity.. My canopy temps are usually under 80f (26c) So heat's not a problem. From mixed sources it didn't seem out of the ordinary to be 12-14" from canopy with temps in check. Many sources I've seen said 16" for daylight equivalent; I'm at 20" now to be safe

piratebug said:

Yeah, for about to start week 5 they do look just fine. Anyhow... what are they growing in, and what are you feeding them, and as for the light, is that a open hood, or a cooled closed hood, and what lamp are you using, brand name?

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I have an air-cooled sun system hood and a vivosun 600w HPS bulb. Growing in pro-mix hp. Feeding General Hydroponics flora series following their drain to waste schedule. I added Koolbloom and Floranectar when flipped to flower. There are two plants in 7 gallon fabric pots. I need to water 2-3 a week, about 3 gallons each pot. Runoff PH has been around 6.

My daylight tent temps are 75-80 and RH of 42%; Critical mass is the strain, shorter flower timeline ~50-55 days - I'm at day 34 now so I only have a week or two before I start flushing.

My current plan, in case there's any nutrient lockout, is to flush them next time with double the water. Then 1/2 dose feedings the next two. that should bring me to week seven, then maybe one more feeding and then just flushing.

This is my first grow but to me it looks the trichomes are already starting to turn white; so I think I maybe only have 2 weeks. I took some closeups with my phone through a loupe:

Actually now that I see the pictures like this I can see they're still clear, so I have some time yet.

They look Nitrogen deficient. 12-18” is fine for an air cooled 600w if temps are in check. I would take it another 2.5-3 weeks at least.

I'd wait some weeks.. 3 to be safe.
Take pics and post here next time you think about chopping
The good ol peeps on riu will help

Critical Canuck said:

Actually now that I see the pictures like this I can see they're still clear, so I have some time yet.

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You have a LONG way to go. Hairs will be 95-100% orange before you should even start looking at trichs. As far as you light goes, I run a similar setup and i keep mine up high so that there is more even coverage of the entire canopy. No reason to blast the center and have everything on the outside starve for light. Commercial growers keep their light 3 feet or more above the canopy.

I try to keep my 600 watt light 20 inches above the canopy. Maybe 18" as the buds grow and reach for the light.

If it's too close or too hot during the last half of flower my buds will get too hot, and foxtail and get a puffy, loose structure. This can give them the hay smell, or make them unhealthy and allow mold to take hold inside the fat top buds. So be careful.

I agree with the other guys that you've got a while to go yet. If you're 5 weeks in you could have another 4 weeks left, easily.

Except for that yellowing it looks like you're doing a solid job. Your screen looks pretty full and your canopy is nice and even. Good Job!

Critical Canuck said:

I posted in the newbie forum yesterday, no response. Trying again here.
I have a 600W HPS in a sun system hood in a 4x4 tent over a scrog.
I had the lights 14" above the canopy during veg (MH) and flipped to flower and HPS and the center mass of the canopy started turning a lighter green.
I figured light burn so I backed off the lights to 18" and it seemed to continue so now I'm up to 20"

So now I'm just trying to figure out if I'm really looking at light burn or a nutrient problem. I don't want to pull the light so far back that it reduces yield.

Canopy-
This was two weeks ago when I first moved the light up to 18"
View attachment 4649590
This is now
View attachment 4649591


Some of the leaves have progressed from lightening to full on looking bleached.

View attachment 4649592 View attachment 4649598 View attachment 4649599

The buds are looking nice now though, I'll be at 5 weeks tomorrow.

View attachment 4649600

Click to expand...

I would consider investing in one of these. The hood you have directs light almost straight down- you want a nice large even canopy spread. Look around for used ones, people sell them for 50-100$ around me all the time.

I'm concerned about bud rot, PM, etc.. There are a lot of leaves in the canopy and the buds can be pretty tight together in some spots.
my RH is at 40% and there are two fans under the canopy and the one bar fan over top. Assuming 3 weeks to go should I even consider removing leaves at this point? Does this look ok or is it still too bushy?



I think I made the mistake of tucking too late, there wasn't a lot of stretch after flipping to flower. So unfortunately most of the bud sites didn't have a lot of vertical growth above the canopy before flowering. I'll see what I get out of it, my first attempt so as long as I get something decent in the end.
Everything is stripped below the net.. Except for the odd popcorn bud just at the canopy level. Figured I'd just leave them there since they're getting light, not sure if it's worth it or not though.

Critical Canuck said:

I'm concerned about bud rot, PM, etc.. There are a lot of leaves in the canopy and the buds can be pretty tight together in some spots.
my RH is at 40% and there are two fans under the canopy and the one bar fan over top. Assuming 3 weeks to go should I even consider removing leaves at this point? Does this look ok or is it still too bushy?

View attachment 4651900

I think I made the mistake of tucking too late, there wasn't a lot of stretch after flipping to flower. So unfortunately most of the bud sites didn't have a lot of vertical growth above the canopy before flowering. I'll see what I get out of it, my first attempt so as long as I get something decent in the end.
Everything is stripped below the net.. Except for the odd popcorn bud just at the canopy level. Figured I'd just leave them there since they're getting light, not sure if it's worth it or not though.

View attachment 4651899

Click to expand...

I definitely would not remove any more leaves until harvest. I think 3 weeks is a bit optimistic.... 4-5 sounds more likely.

JoeBlow5823 said:

I would consider investing in one of these. The hood you have directs light almost straight down- you want a nice large even canopy spread. Look around for used ones, people sell them for 50-100$ around me all the time.

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Yeah that would be nice, can't seem to find anything like that around here or online.. I'm in Canada so options are a bit more limited.

Critical Canuck said:

Yeah that would be nice, can't seem to find anything like that around here or online.. I'm in Canada so options are a bit more limited.

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I would raise the one youve got then.

JoeBlow5823 said:

I definitely would not remove any more leaves until harvest. I think 3 weeks is a bit optimistic.... 4-5 sounds more likely.

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Ok, cool.. I'm just going by the Critical Mass 6-8 weeks guideline, starting week six tomorrow. They'll be ready when they're ready I guess.
I have the light up at 20" now.

I would defoliate. I don't like when leaves are bunched up on one another. The plants transpire and leaf on leaf contact makes it harder for the transpiration to evaporate.

NukaKola said:

I would defoliate. I don't like when leaves are bunched up on one another. The plants transpire and leaf on leaf contact makes it harder for the transpiration to evaporate.

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I'll take another look tomorrow to see if there are any leaves that are too crowded and not getting enough air flow. I won't remove anything unless it's obvious that it should be.

Critical Canuck said:

I'll take another look tomorrow to see if there are any leaves that are too crowded and not getting enough air flow. I won't remove anything unless it's obvious that it should be.

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Just check where the leaves are overlapping and touching and make sure there is no moisture build-up. If you have good ventilation and RH isn't too high you should be fine.

May I ask you how did you solve watering-runoff. Do you have some systems?

Bukvičák said:

May I ask you how did you solve watering-runoff. Do you have some systems?

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I see that you have some boxes under the pots, but not sure if you have only 2 plants or 4...? I always have issues with watering plants at the back when went scrog in whole tent. I have tried p-scrog on each plant separate but not sure if flowers being stressed when moved for watering and putting back under the light in different position where it was before. Do not know what costs more work, if normal or individual, so thinking about get back to normal but still looking for a solution how to simply figure out watering and collecting runoff in “hand“ watering system.