3500 color temp?

[Porky101]

Nope! But up to 90°F would be probably okay. I would go for 85-86°F leaf temps with CO2 and 82-83°F without. The needed RH is already in a critical high range in the mid eighties. With lower RH/high VPD you need to lower the nutrient strength to avoid issues. Would be a balance act to keep the plants happy. But there is a rule of thumb. When VPD is 20% too high you need to lower the nutrient strength by 20%.

Im not arguing with you atall, but I would like to challenge this....my plants have grown just fine under HPS @ 90F ambient temps. Surely, if under LED, you can say that 95F under LED is = to 90F under HPS. The hps does warm the plant up a lot!!!

So ye....I will test further but when I think about it, it makes sense too me that with LED you can go "higher temps" than an HPS because the HPS makes the temps higher ANYWAYS?? around the plant? if you get what im saying!

Peace-

 

[goofy81]

I try to keep my VPD under 1.6 kilopascals. Currently due too environmental issues my VPD has been at 1.7 for the past three days. Plants dont seem to mind, they look happy. But I will try lower it once I get more equipment!

I can never get my VPD in that range. Even on best of days I can get about 1.2 but I know some greenhouses aim for 0.7-1.2. For the last 4 weeks it's been 0.4-0.7 and my plants are drinking 5 litres a day each atm! I have never observed any difference in plant drinking rate ( going by pot weight ) from 0.4kpa to 1.2kpa.
So are our "weeds" more resilient than we give them credit for?

Edit: Not everyone may experience similar results. I believe my ceiling fans help offset such a humid environments (based on no fact or evidence)

 

[Randomblame]

Im not arguing with you atall, but I would like to challenge this....my plants have grown just fine under HPS @ 90F ambient temps. Surely, if under LED, you can say that 95F under LED is = to 90F under HPS. The hps does warm the plant up a lot!!!

So ye....I will test further but when I think about it, it makes sense too me that with LED you can go "higher temps" than an HPS because the HPS makes the temps higher ANYWAYS?? around the plant? if you get what im saying!

Peace-

Yeah, this was not meant to argue with you, buddy. I messed up numbers...
I think so: When with HPS leaf temps are usually 2-3° higher than ambient and with LED's it's 1-2° less than ambient. With 92-93°F leaf temps ambient temperature should be already near 95°F.
It's good that you try to fathom where the limits are with LED and CO².
That's the only way to find out if its does well, harm them or not cares them. Especially for those who live in hot areas it would be good to know where the real limit is with LED and CO² and without.

 

[Randomblame]

I can never get my VPD in that range. Even on best of days I can get about 1.2 but I know some greenhouses aim for 0.7-1.2. For the last 4 weeks it's been 0.4-0.7 and my plants are drinking 5 litres a day each atm! I have never observed any difference in plant drinking rate ( going by pot weight ) from 0.4kpa to 1.2kpa.
So are our "weeds" more resilient than we give them credit for?

Edit: Not everyone may experience similar results. I believe my ceiling fans help offset such a humid environments (based on no fact or evidence)

Yeah, a too low VPD is less stressful than a too high. As long as the stomata stay open they should transpire enough. To stop transpiration it would need +90% RH like in a propagator.
0,7-1,2 is the optimal range for late veg/early bloom and if you keep it to the end you can easily compensate for that with a slightly higher ppm. At 1.6 they would probably need 6l with only 800ppm nutrient strength; with 1,2 they drink 5l but probably with up to 950-1000ppm.
In the end, both should lead to similarly good results.

Are you sure it's 0,4-0,7 in the last weeks? This would mean you have ~80% humidity in late bloom..?!

 

[Porky101]

Yeah, a too low VPD is less stressful than a too high. As long as the stomata stay open they should transpire enough. To stop transpiration it would need +90% RH like in a propagator.
0,7-1,2 is the optimal range for late veg/early bloom and if you keep it to the end you can easily compensate for that with a slightly higher ppm. At 1.6 they would probably need 6l with only 800ppm nutrient strength; with 1,2 they drink 5l but probably with up to 950-1000ppm.
In the end, both should lead to similarly good results.

Are you sure it's 0,4-0,7 in the last weeks? This would mean you have ~80% humidity in late bloom..?!

View attachment 4200616

View attachment 4200617

I know it sounds crazy,

funny thing is, I am running 90F, 75% RH and all the pests seem too have died out Plants are looking great. Having one of the hottest days on record and boy am I glad I invested in my LEDS, If I was still using my thousies I cant imagine the heat in there! the plants would have been toast.

I havent had rot in ages.

*My unrooted clones without humidity domes seem too be dying real fast in this heat

 

[goofy81]

Hey I've noticed a lot of dead bugs at high humidity too.

If you guys Google up "lies our father told us humidity" there is even a massive thread on experiences of growing with high humidity.

@Randomblame that's right dude 70-80% during flower even. It's almost impossible to get a room filled with half vegetation to low humidity levels.
My plants are already at the stage where I cannot adjust the lights without breaking branches!

 

[ttystikk]

I just got a bridelux strip led light built using the 3500k color temp and was wondering if anybody here is using that temp with success? I'm not sure what it might be but some seedlings have been under the light for about a week and still look weak so I brought out my old trusty 150 hps and they seem better after just one day. I'm wondering of I should have went with the 3000k temp instead.

Almost every light I have is 3500K. I'm very happy with the results.

 

[ttystikk]

Hey I've noticed a lot of dead bugs at high humidity too.

If you guys Google up "lies our father told us humidity" there is even a massive thread on experiences of growing with high humidity.

@Randomblame that's right dude 70-80% during flower even. It's almost impossible to get a room filled with half vegetation to low humidity levels.
My plants are already at the stage where I cannot adjust the lights without breaking branches!

I took a lot of heat for growing in 75% RH back in the day but the plants liked it.

I generally listen to the plants rather than people lol

 

[GBAUTO]

Hey I've noticed a lot of dead bugs at high humidity too.

If you guys Google up "lies our father told us humidity" there is even a massive thread on experiences of growing with high humidity.

@Randomblame that's right dude 70-80% during flower even. It's almost impossible to get a room filled with half vegetation to low humidity levels.
My plants are already at the stage where I cannot adjust the lights without breaking branches!

Have to agree, to a point...
On my indoor grows, it's not unusual for me to see room humidity over 70% but I never have any problems during flower because of the airflow in the room. Outdoors is another story. I live in the Smokies and fog is usually a daily occurrence. I routinely will have colas that develop bud rot-same high humidity conditions I have indoors but no airflow.

 

[Randomblame]

Have to agree, to a point...
On my indoor grows, it's not unusual for me to see room humidity over 70% but I never have any problems during flower because of the airflow in the room. Outdoors is another story. I live in the Smokies and fog is usually a daily occurrence. I routinely will have colas that develop bud rot-same high humidity conditions I have indoors but no airflow.

I usually use a shit load of McDonald's straws on my outdoor plants when it gets too late in october. I cut them in halves which I put in between the fattest buds. So that moisture inside can escape more easily with the wind.(chimney effect)
Looks crazy, like as they come with curlers from the hairdresser, lol! But as long as it helps ..