some plants hate light?

Splinter7

Splinter7

Well-Known Member
coreywebster said:
Try upping your temps 5 degrees and see what happens.

Also I thought you wrote you'd changed your lighting?
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i always ran leds for the last 8 years. last grow i changed to QB style lights S33 from ACI. ~270w at 100%, right now running 157w at 60%. was running at 127, same problem. last grow i was successful wit this light during veg, but all the high pct indica plants didn't like the light. sativas/hybrids loved it. this wilting thing is new to this light for some strains apparently.

what does higher temps do? i had it at 82 for while when the lights were lower...no venting then. it got hot when i cranked up the light and i started venting the heat. last time i ran a dedicated AC for the room to get input temp low. plants loved it, except the indicas.

VPD is 1.55, humidity is low at 45%. would higher humidity help?
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
Splinter7 said:
i always ran leds for the last 8 years. last grow i changed to QB style lights S33 from ACI. ~270w at 100%, right now running 157w at 60%. was running at 127, same problem. last grow i was successful wit this light during veg, but all the high pct indica plants didn't like the light. sativas/hybrids loved it. this wilting thing is new to this light for some strains apparently.

what does higher temps do? i had it at 82 for while when the lights were lower...no venting then. it got hot when i cranked up the light and i started venting the heat. last time i ran a dedicated AC for the room to get input temp low. plants loved it, except the indicas.

VPD is 1.55, humidity is low at 45%. would higher humidity help?
Click to expand...
As to whether more humidity would help or not, generally you don't need to be so low in veg, or early veg. I try to start my seedlings around 70% and keep them in the low to mid 60's for flower. I aim at 81-84f degrees during lights on (when factoring in a LST of -2f degrees that means 79-82f) and for lights out 75f-78f. That places me in the range of .9-1.3 for VPD.

...But then when I have seedlings, they're under 200PPFD for the first week then up to 300-350 for the next week or two before I ramp it up for rest of the grow.
 
Splinter7

Splinter7

Well-Known Member
LeastExpectedGrower said:
As to whether more humidity would help or not, generally you don't need to be so low in veg, or early veg. I try to start my seedlings around 70% and keep them in the low to mid 60's for flower. I aim at 81-84f degrees during lights on (when factoring in a LST of -2f degrees that means 79-82f) and for lights out 75f-78f. That places me in the range of .9-1.3 for VPD.

...But then when I have seedlings, they're under 200PPFD for the first week then up to 300-350 for the next week or two before I ramp it up for rest of the grow.
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i have exhaust. so, when i add a humidifier it doesn't do anything to the RH. if i stop the exhaust it gets hot...over 90f. i am not fully in control of the RH when i control temp. your ppfd schedule seems normal. that's sort of what i would have done. my last grow i tried to keep it as cold as possible because it helps keep the plants short. it worked. this time, they are stretching....that is very different. heat is higher since no AC running in the room. humiidity is higher than last time...it was 35-40% b/c of the AC. when i was running the humidifier with no exhaust i was at 0.9 to 1.1 vpd. now it's too high. how are you controlling all of this? or, is it just happenstance? i live in the south. there is no sub 70 temp unless you want a 500 dollar electric bill. it's 85 outside and i keep my house a bout 8 degrees cooler than anyone i know. i actually ran 69 house temp during that last grow...it was pricey. maybe setting a humidistat controller on the exhaust circuit would work? i have two of them i use for drying.
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
Splinter7 said:
i have exhaust. so, when i add a humidifier it doesn't do anything to the RH. if i stop the exhaust it gets hot...over 90f. i am not fully in control of the RH when i control temp. your ppfd schedule seems normal. that's sort of what i would have done. my last grow i tried to keep it as cold as possible because it helps keep the plants short. it worked. this time, they are stretching....that is very different. heat is higher since no AC running in the room. humiidity is higher than last time...it was 35-40% b/c of the AC. when i was running the humidifier with no exhaust i was at 0.9 to 1.1 vpd. now it's too high. how are you controlling all of this? or, is it just happenstance? i live in the south. there is no sub 70 temp unless you want a 500 dollar electric bill. it's 85 outside and i keep my house a bout 8 degrees cooler than anyone i know. i actually ran 69 house temp during that last grow...it was pricey. maybe setting a humidistat controller on the exhaust circuit would work? i have two of them i use for drying.
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Look into a system where you've got more control over your fans. I don't have AC but do have fans that are triggered by either temp or humidity and ramp up or down accordingly and it's worked like a charm and allows me to use a small humidifier in the tent as well as both an intake and exhaust fan.
 
Blue brother

Blue brother

Well-Known Member
How are you measuring ur vpd? I’d get an ir thermometer on that leaf to see what’s really going on. But still imo 1.55 is way too much, I’d wanna be under 1 at that stage. Also ur method of going from soil to hydro terrifies me lol but each to their own
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
Blue brother said:
How are you measuring ur vpd? I’d get an ir thermometer on that leaf to see what’s really going on. But still imo 1.55 is way too much, I’d wanna be under 1 at that stage. Also ur method of going from soil to hydro terrifies me lol but each to their own
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Agree. I like the Pulse charts for veg and flower...1.5 puts you outside the 'comfort zone'. But definitely knowing your LST so you can accurately calculate your VPD is important. Because that changes the end calculation.
 
Splinter7

Splinter7

Well-Known Member
Blue brother said:
How are you measuring ur vpd? I’d get an ir thermometer on that leaf to see what’s really going on. But still imo 1.55 is way too much, I’d wanna be under 1 at that stage. Also ur method of going from soil to hydro terrifies me lol but each to their own
Click to expand...

Guvee wifi meter real time. It's usually colder with laser thermometer. The soil to hydro works fine. There isn't a lot of dirt/coco....about 4oz and 20pct of it is already perlite. It's just like a jiffy or doing perlite only, just rooting. I used to break up the root ball but transplant recovery took longer.
 
coreywebster

coreywebster

Well-Known Member
Splinter7 said:
i always ran leds for the last 8 years. last grow i changed to QB style lights S33 from ACI. ~270w at 100%, right now running 157w at 60%. was running at 127, same problem. last grow i was successful wit this light during veg, but all the high pct indica plants didn't like the light. sativas/hybrids loved it. this wilting thing is new to this light for some strains apparently.

what does higher temps do? i had it at 82 for while when the lights were lower...no venting then. it got hot when i cranked up the light and i started venting the heat. last time i ran a dedicated AC for the room to get input temp low. plants loved it, except the indicas.

VPD is 1.55, humidity is low at 45%. would higher humidity help?
Click to expand...
It's pretty common to run higher temps to keep that leaf surface temp up.

Weirdly in flower I dont have to worry
But when I used to veg with LED I'd have to be 82-85 to get plants thriving.

I use CMH or MH for veg because it's just less effort in winter.

Anyhow, if you set your temps higher your fans would be slower and your RH would be a bit higher. Fairly confident you'd see happier plants
 
Splinter7

Splinter7

Well-Known Member
LeastExpectedGrower said:
it can be calibrated but there's no offset available in the app to deal with LST, unless that's just been added. I have one, but don't use it these days since the AC Infinity app does have a LST offset to calculate accurate VPD.
Click to expand...

i had always thought air temp didn't make a lot of sense for vpd. hadn't heard of this until now., but you can absolutely adjust temp according to leaf temp differential. it's not going to be constant across the tent and may need adjustment if you change anything, so getting close directionally should be fine...it's just ball park if you are at 1 you are lower than if you are at 1.5. i don't see the advantage with ACI, is it doing something dynamically? an offset that is static doesn't seem any better than the offset/calibration in the govee i have.
 
Splinter7

Splinter7

Well-Known Member
coreywebster said:
It's pretty common to run higher temps to keep that leaf surface temp up.

Weirdly in flower I dont have to worry
But when I used to veg with LED I'd have to be 82-85 to get plants thriving.

I use CMH or MH for veg because it's just less effort in winter.

Anyhow, if you set your temps higher your fans would be slower and your RH would be a bit higher. Fairly confident you'd see happier plants
Click to expand...

my fans run the same no matter what. only have the ACI lighting. i may try adding the humidistat controller to the system and see if things perk up. i hope it is just humidity, but i am already seeing an improvement in the plant i move out from under the light. still thinking the light is not liked.
 
LeastExpectedGrower

LeastExpectedGrower

Well-Known Member
Splinter7 said:
i had always thought air temp didn't make a lot of sense for vpd. hadn't heard of this until now., but you can absolutely adjust temp according to leaf temp differential. it's not going to be constant across the tent and may need adjustment if you change anything, so getting close directionally should be fine...it's just ball park if you are at 1 you are lower than if you are at 1.5. i don't see the advantage with ACI, is it doing something dynamically? an offset that is static doesn't seem any better than the offset/calibration in the govee i have.
Click to expand...
It gives a constant accurate VPD and logs/graphs it and also you get an accurate environmental temp and humidity reading. You can also program the controller to turn on/off humidifiers or dehumidifiers (or fans) based on VPD, so if that's a number that you're interested in, you can narrow it down pretty well.
 
Richard Drysift

Richard Drysift

Well-Known Member
Splinter7 said:
100% perlite. i start in organic soil...really small cup....like instead of a jiffy which always claims my claims seedlings as DOA.
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Splinter7 said:
ph was off in the soil ph, always is. ph is perfect now 5.7/5.8.

soil is wet in those pics from the day before.
there is a half gallon reservoir at the bottom.
tons of water.
they can't be overwatered. tested many times in this medium. you water 4x a day or 2x a week. doesn't matter.
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Probably is impossible to overwater in mostly just perlite but that doesn’t mean it’s a good choice of medium. If you simply added worm castings or an ewc aact to your organic soil mix you would not need ph perfect or much else other than water; maybe a fertilizer and/or mineral input. Just my advice but definitely has nothing to do with lighting. Plants don’t hate
 
Splinter7

Splinter7

Well-Known Member
Richard Drysift said:
Probably is impossible to overwater in mostly just perlite but that doesn’t mean it’s a good choice of medium. If you simply added worm castings or an ewc aact to your organic soil mix you would not need ph perfect or much else other than water; maybe a fertilizer and/or mineral input. Just my advice but definitely has nothing to do with lighting. Plants don’t hate
Click to expand...
i've done this for years and out perform my buddy's soil grows by over 2x. it works really well. 50g/sqft. 49 day veg. the advantage is work for how fast it grows. i used to do 5 gallon buckets and I could water once ever 5 days and get super fast grows. it was crazy. could go a week if needed or water ever 2 days. it didn't matter until late flower when it was ever 3 or 4 days. now in a 2g it's ever 2 to 4 day, but you can water or flush whenever you want. get the ppm back to tap water levels, then drop nutes again. super small amount of nutes too. i just mix half gallon per plant per water, about 2x per week on avg. costs nothing.
 
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Splinter7

Splinter7

Well-Known Member
LeastExpectedGrower said:
It gives a constant accurate VPD and logs/graphs it and also you get an accurate environmental temp and humidity reading. You can also program the controller to turn on/off humidifiers or dehumidifiers (or fans) based on VPD, so if that's a number that you're interested in, you can narrow it down pretty well.
Click to expand...

i have the first part. i just tested using a humidistat. i am not messing with that. i don't want an 90f tent. i ran a very cold tent last time and got squat plants. i need that. i have a height limit. tent is 5ft tall.
 
Blue brother

Blue brother

Well-Known Member
If the vpd is too great on the plant she will close her stomata in a last ditch attempt to stop transpiration which will stress her and you’ll get symptoms of light tox or over heat, and this is actually what is happening, the plant can’t use the light because it’s not transpiring so it displays light tox symptoms

not saying this is deffo what it is but just trying to rule some things out for you, and in future best practise is to have a lower vpd at this point, my plants get 1.5-1.8 during the most demanding phase of flower and even then I sometimes need to back off from 1.8
 
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