Halide 5ft above seedling canopy

Hi Guys,

Am in a bit of a fix. Your experienced advice would be greatly appreciated. Here is what I'm woking with,

OG Kush
DWC
400 MH- 18/6
PPM 330-500pm
7 Plants
Nutes AN Jungle Juice series + Sensi Cal Mag + Voodoo Juice
Ph 5.6-5.8
Tropical climate 80-97F RH- 68%
Transferred from coco starter plug to bare root.
Home- Steel grow cabinets qyt 2
Previous Home - 4ft Height cabinet
Current Home - 6ft Height cabinet


I've got a couple of 3 week old seedlings in a grow cabinet under a 400 watt MH. Its placed 5 ft above the plant canopy. With an running A/C stable temps at 70-72F RH 45%- Light

They were initially placed in a smaller cabinet about 3 feet above the canopy. No A/C- ventilated with standard intake and exhaust fans. Some of my seedlings were wilting and looked sad. Noticed slow growth as well. I consulted through posting my concerns and some well known members replied and said the problems were due to the high temps- 88-97F.

So I moved them into the taller grow cabinet few hours ago.

Both light fixtures cannot be raised or lowered in both cabinets.

My question is should I increase my wattage from a 400 watt MH to a 1000Watt MH since the light source is further away? Also, will they perk up in their new environment.

Thank you!!

Seedlings. If it were me I would keep the light where you have it. Get the temps to 78% see how they respond to that. Raise the plants up to the light if need be. Others may have better advice for you.

Get the light as close as you can keeping the temps in range. I can get mine about two feet off them in a cool tube.

above for the Halide, right is for HPS ....both inches, something for you to work by, ....just add a factor of raising it another 33%, keep temp tool close.

good luck

Bose said:

Seedlings. If it were me I would keep the light where you have it. Get the temps to 78% see how they respond to that. Raise the plants up to the light if need be. Others may have better advice for you.

Click to expand...

Thank you so much, Bose for your quick response !!

Big Thanks Kiwipaulie!! Will do that as well!!

Mamba01 said:

Thank you so much, Bose for your quick response !!

Click to expand...

Some good advice from above posts. @vostok well lead you in the right direction. Good luck

Thank you for this very helpful chart Vostok! Wow got some work to do!

The problem you are having is you need to dial things in and keep it stable!
Try this out untill you get the hang of things,
For seedlings aim for 75-80f at 55-75% rh
After 4th node go for 72-77f at 50-65% rh
In flower go for 70-75f at 40-50% rh

You can start the MH at 3-4ft with seedlings, but drop it an inch every few days untill you find a sweet spot for growth without heat stress/light bleaching and take note of how much quicker the soil dries so you dont accidentally over/under water. If you cant raise/lower the lights then you better get some bricks or something to raise the pots lol

Good luck

*edit -use the chart vostok posted!

SPLFreak808 said:

The problem you are having is you need to dial things in and keep it stable!
Try this out untill you get the hang of things,
For seedlings aim for 75-80f at 55-75% rh
After 4th node go for 72-77f at 50-65% rh
In flower go for 70-75f at 40-50% rh

You can start the MH at 3-4ft with seedlings, but drop it an inch every few days untill you find a sweet spot for growth without heat stress/light bleaching and take note of how much quicker the soil dries so you dont accidentally over/under water. If you cant raise/lower the lights then you better get some bricks or something to raise the pots lol

Good luck

*edit -use the chart vostok posted!

Click to expand...

Agreed! SPLFreak808,

Thank you so much for this incredibly helpful temp guidance!

Had started them out kinda wacky, Just finished rearranging their new set up. Not going to fidget with them anymore! Gonna leave them be. Until progressive growth is seen. And new roots forming. Yeah , just got crafty and used all my damaged DWC buckets lol!

My new set up for visual reference. A big thanks to you all for your outstanding guidance!!

Mamba01 said:

My new set up for visual reference. A big thanks to you all for your outstanding guidance!! View attachment 3683018

Click to expand...

Id try and get that light lower. To me they are no longer seedlings.

Here's some seedling that will be two weeks old tomorrow. I'm running my 400w mh about two foot off, but that's in a cooltube hooked up to a 4" centrifugal fan.

My temps sit at 25-26c (77f) running at 650ppm

SPLFreak808 said:

The problem you are having is you need to dial things in and keep it stable!
Try this out untill you get the hang of things,
For seedlings aim for 75-80f at 55-75% rh
After 4th node go for 72-77f at 50-65% rh
In flower go for 70-75f at 40-50% rh

You can start the MH at 3-4ft with seedlings, but drop it an inch every few days untill you find a sweet spot for growth without heat stress/light bleaching and take note of how much quicker the soil dries so you dont accidentally over/under water. If you cant raise/lower the lights then you better get some bricks or something to raise the pots lol

Good luck

*edit -use the chart vostok posted!

Click to expand...

That is better than just posting a basic chart. The chart does not mention the near perfect airflow you need to pull off those closest distances. If a fan or timer fails, and the lights get a few hours beaming at that close a range?. It also does not warn you of growth, miss a day/half day check and they have grown into the ''too hot'' zone.

From what I've read the closer ranges burn off potency as well.

kiwipaulie said:

Id try and get that light lower. To me they are no longer seedlings.

Here's some seedling that will be two weeks old tomorrow. I'm running my 400w mh about two foot off, but that's in a cooltube hooked up to a 4" centrifugal fan.

My temps sit at 25-26c (77f) running at 650ppm

Click to expand...

WOW Your plants look gorgeous!!

Thanks for the correction. Noted! I was a bit careless after they sprouted. I did not transfer them into DWC until 2 weeks into their growth. In which I felt stunted them.

They were transplanted about a week back in these 5gallon DWC.

PPM 330-500

I think they are now in the process of recovering from heat stress and shock, hence the droopy and wilted lower leaves. New growth seems to look ok so far. Finger crossed. Hope they will pick up in another week..

Unfortunately, I am unable to lower the light source. Its mounted on the top of my cabinet.

Was considering going for a 1000watt MH to make up for the space gap??..

Mamba01 said:

WOW Your plants look gorgeous!!

Thanks for the correction. Noted! I was a bit careless after they sprouted. I did not transfer them into DWC until 2 weeks into their growth. In which I felt stunted them.

They were transplanted about a week back in these 5gallon DWC.

PPM 330-500

I think they are now in the process of recovering from heat stress and shock, hence the droopy and wilted lower leaves. New growth seems to look ok so far. Finger crossed. Hope they will pick up in another week..

Unfortunately, I am unable to lower the light source. Its mounted on the top of my cabinet.

Was considering going for a 1000watt MH to make up for the space gap??..

Click to expand...

Cheers. Its my first dwc run. Personally I think you need to get a shade and be able to lower your light, otherwise they will just stretch. Are you going to scrog them? You don't really have much height with those buckets sitting on the other ones.

kiwipaulie said:

Cheers. Its my first dwc run. Personally I think you need to get a shade and be able to lower your light, otherwise they will just stretch. Are you going to scrog them? You don't really have much height with those buckets sitting on the other ones.

Click to expand...

This my third DWC run and it was surprisingly successful the first White Widow. Second was a disaster Super Silver Haze. Now OG Kush. Right, will check it out. Am for sure going to scrog them. It's a 3ft space gap, Am going to look into lowering the light source asap. Cheers

Flowki said:

That is better than just posting a basic chart. The chart does not mention the near perfect airflow you need to pull off those closest distances. If a fan or timer fails, and the lights get a few hours beaming at that close a range?. It also does not warn you of growth, miss a day/half day check and they have grown into the ''too hot'' zone.

From what I've read the closer ranges burn off potency as well.

Click to expand...

Interesting point Flowki, Thank you for you input! So much to learn so many insights. Incredible!