I have a hermie. Don't know what to do or to expect.

FirstCavApache64

Well-Known Member
With my light spectrum 60,000 LUX is 1,069 ppfd. 70,000 is 1250 ppfd. Here's a link with some helpful conversion factors to convert lux into ppfd depending on the spectrum of your light.

Just enter in your light as close as you can and it with give you a ballpark of ppfd. The only real way to get accurate numbers is with a quantum meter but lux will give you benchmarks that you can apply to get close enough in my opinion. I guess it's possible if you put the light super close to the plants it would raise leaf surface temp but every grow I've done my leaves have been roughly 3° cooler than ambient. These are healthy leaves I'm checking though. Due to a heat wave in VA the last few days my VPD has been around 1.6 and the plants are taking it fine. I'm giving them extra water and food as they're running wide open throttle in week 6 of flower.
 

RookieMuffin

Well-Known Member
Yep, replace your batteries and have a look but just assume 2-3f less than ambient for now. They’ve got a month to go yet at least, if you can keep them alive that long. The lux meter might also be talking smack, so I’d cross reference with the manufacturer guidelines on hanging height to see if the readings make sense. What lights are they?
spiderfarmer SF 4000.... they were a little under the recommended 18 inch but thats still 1400ppfd on 100% based on their ppfd map.... and since my light was closer than 18 inch it was even more .... on 12 inch their ppfd map says max 1900 ppfd.... so yeah it was a lot!! I think i fried them....

What do you think are the chances of recovering? How much should i dim them down? I think i should dim a lot for them to recover right...?
 

bubblescrogs

Well-Known Member
In my vegging tent the thermometer read same leaf temp as room temp... so yeah I think the thermometer is working fine... maybe the leafs are so hot because they dont transpire anymore because the leafs are very dry and crisp... what do you think?
I think it’s a symptom rather than a cause. Get the light dialed in first before worrying about vpd. If you’ve got some head room, move them right up for a few days and see if they start to recover (those fried ones never will) and start feeding again.
 

RookieMuffin

Well-Known Member
With my light spectrum 60,000 LUX is 1,069 ppfd. 70,000 is 1250 ppfd. Here's a link with some helpful conversion factors to convert lux into ppfd depending on the spectrum of your light.

Just enter in your light as close as you can and it with give you a ballpark of ppfd. The only real way to get accurate numbers is with a quantum meter but lux will give you benchmarks that you can apply to get close enough in my opinion. I guess it's possible if you put the light super close to the plants it would raise leaf surface temp but every grow I've done my leaves have been roughly 3° cooler than ambient. These are healthy leaves I'm checking though. Due to a heat wave in VA the last few days my VPD has been around 1.6 and the plants are taking it fine. I'm giving them extra water and food as they're running wide open throttle in week 6 of flower.
I've used this site too but when I compare it to the ppfd map of the manufacteurer it doesnt add up... Mnaufacteurer says 1900ppfd and the website says 1000-1200 ... so who should i trust...? I think the manufacteurer ppfd map is closer to the real ppfd sinc ethey have measured it with this exact lamp right..? and based on that i have fried the shit out of them with the 100% setting...
 

RookieMuffin

Well-Known Member
I think it’s a symptom rather than a cause. Get the light dialed in first before worrying about vpd. If you’ve got some head room, move them right up for a few days and see if they start to recover (those fried ones never will) and start feeding again.
Ok so you say dimming the light down (or raising the light) was the right decision? I've dimmed them to about 60% i think (idk right now because lights are off i cant look)

I check the EC all the time... so now i should just wait till the EC is falling again instead of raising? and if its falling they started eating again.... I hope they will recover...
 

bubblescrogs

Well-Known Member
Ok so you say dimming the light down (or raising the light) was the right decision? I've dimmed them to about 60% i think (idk right now because lights are off i cant look)

I check the EC all the time... so now i should just wait till the EC is falling again instead of raising? and if its falling they started eating again.... I hope they will recover...
I’d probably move them further away if you can, rather than just turning them down. You might still be getting hot spots if they are really close. What EC are you running (and what medium)? I’d say lift them as far away as you can and set the strength based on manufacturer measurements to get around 900.
 

FirstCavApache64

Well-Known Member
I've used this site too but when I compare it to the ppfd map of the manufacteurer it doesnt add up... Mnaufacteurer says 1900ppfd and the website says 1000-1200 ... so who should i trust...? I think the manufacteurer ppfd map is closer to the real ppfd sinc ethey have measured it with this exact lamp right..? and based on that i have fried the shit out of them with the 100% setting...
I think the manufacturer probably has the highest possible numbers they can come up with to make the light more attractive and marketable. Learning to read the plants response to light changes takes time and experience. Raising it or lowering the ppfd by dimming it is always a good idea when you see signs of stress in the plant. It gives them a chance to recover.
 

RookieMuffin

Well-Known Member
I’d probably move them further away if you can, rather than just turning them down. You might still be getting hot spots if they are really close. What EC are you running (and what medium)? I’d say lift them as far away as you can and set the strength based on manufacturer measurements to get around 900.
It's hard to dial it in this way because 900ppfd at a given hight and percentage is a lot of variables.... I could get the light easy 32 inches (81cm) away from canopy... wouldn't that be to much?

And just hang it higher and dim it down? just to let them recover?

And what do you think about the vpd problem? Raise the RH while they are recovering to lower the VPD so they maybe recover better?

Im running at 2.0 EC right now. Before in vegging they were at 2.3 and they were eating very good... EC always stayed spot on 2.3 not lower not higher and they looked very healthy. Until i initiated flowering and increased light intensity....

Now i run them at 2.0 EC in DWC hydro. but the EC is rasing all the time since 1 month (maybe due to the high light intensity?) so i was just adding water to the res every day....
 

RookieMuffin

Well-Known Member
I think the manufacturer probably has the highest possible numbers they can come up with to make the light more attractive and marketable. Learning to read the plants response to light changes takes time and experience. Raising it or lowering the ppfd by dimming it is always a good idea when you see signs of stress in the plant. It gives them a chance to recover.
Ok so I will raise the light and dim it down so they can recover from the light stress... What do you say about 22 inch (56cm) from canopy and about 60% dimmed? Is it too high and dimmed too low or is that a good start to let them recover?
 

RookieMuffin

Well-Known Member
I don't know what happens to the potency and yield of the run if I raise the lamp to much and dim it too low... I don't want to make it "bad weed"
 

bubblescrogs

Well-Known Member
It's hard to dial it in this way because 900ppfd at a given hight and percentage is a lot of variables.... I could get the light easy 32 inches (81cm) away from canopy... wouldn't that be to much?

And just hang it higher and dim it down? just to let them recover?

And what do you think about the vpd problem? Raise the RH while they are recovering to lower the VPD so they maybe recover better?

Im running at 2.0 EC right now. Before in vegging they were at 2.3 and they were eating very good... EC always stayed spot on 2.3 not lower not higher and they looked very healthy. Until i initiated flowering and increased light intensity....

Now i run them at 2.0 EC in DWC hydro. but the EC is rasing all the time since 1 month (maybe due to the high light intensity?) so i was just adding water to the res every day....
Going by this I’d bump it up to 19” and leave it at 100%. Drop the EC too, some phenos will take that when they are healthy but if it’s not dropping 0.1ec every day or two, it’s too high. I’d be about 1.5 at this stage. But if it’s not dropping, it’s too high. https://cdn.shopify.com/s/files/1/0583/4522/6437/files/SF4000_chart_Insta_480x480.png?v=1642597455
 

RookieMuffin

Well-Known Member
I’d probably move them further away if you can, rather than just turning them down. You might still be getting hot spots if they are really close. What EC are you running (and what medium)? I’d say lift them as far away as you can and set the strength based on manufacturer measurements to get around 900.
This is the ppfd map of the manufacteurer. At 22 inch... so to get 900 ppfd at 22 inch it would be probably around 80% or so... what do you think?

hanging lights at 22 inch and 60% dimmed is too low ppfd? or what whould you recommend?
 

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RookieMuffin

Well-Known Member
Going by this I’d bump it up to 19” and leave it at 100%. Drop the EC too, some phenos will take that when they are healthy but if it’s not dropping 0.1ec every day or two, it’s too high. I’d be about 1.5 at this stage. But if it’s not dropping, it’s too high. https://cdn.shopify.com/s/files/1/0583/4522/6437/files/SF4000_chart_Insta_480x480.png?v=1642597455
They were about 17 inch or so at 100% and that was too much so i think 19 at 100 is too much too... if we count in the high leaf temps due to light too close i think its still too close...

Manufacteurer ppfd map for 18 inch at 100% is this

Screenshot_2344GSE1.png

Your picture might be a old ppfd map?

This is the ppfd map of the manufacteurer.

Manufateurer also says PPE: 2.7umol/J

Ok so mid flower you would already lower the EC to 1.5?
 

bubblescrogs

Well-Known Member
The
They were about 17 inch or so at 100% and that was too much so i think 19 at 100 is too much too... if we count in the high leaf temps due to light too close i think its still too close...

Manufacteurer ppfd map for 18 inch at 100% is this

View attachment 5281814

Your picture might be a old ppfd map?

This is the ppfd map of the manufacteurer.
The one I posted is from a third party site who measures many lights. They tested it a year ago. It’s good to remember all the variables interplay ie. The light might be ok for a healthy plant that is dropping ec everyday. So back the light and ec right off for now until they improve and then you can start to dial them up a bit once healthy and starting to eat again

 

RookieMuffin

Well-Known Member
The

The one I posted is from a third party site who measures many lights. They tested it a year ago. It’s good to remember all the variables interplay ie. The light might be ok for a healthy plant that is dropping ec everyday. So back the light and ec right off for now until they improve and then you can start to dial them up a bit once healthy and starting to eat again

Ok. As soon as the light turns back on i will raise it to 22 inch and dim it to 80%. I will also lower the EC and see how they react to that. Ok?

Thanks for the link i will check it out right now.
 

bubblescrogs

Well-Known Member
Ok. As soon as the light turns back on i will raise it to 22 inch and dim it to 80%. I will also lower the EC and see how they react to that. Ok?

Thanks for the link i will check it out right now.
Sounds a plan. I’d be more worried about the EC to be honest. High vpd you want to run less EC because they are feeding harder. Drop it way down to like 1.4, bump the humidity a bit for a few days so they aren’t feeding so hard and see if they start to recover. I’ve run silly high ppfd with healthy plants and they didn’t fry, just weird foxtails, bleaching and nanas.
 

RookieMuffin

Well-Known Member
Sounds a plan. I’d be more worried about the EC to be honest. High vpd you want to run less EC because they are feeding harder. Drop it way down to like 1.4, bump the humidity a bit for a few days so they aren’t feeding so hard and see if they start to recover. I’ve run silly high ppfd with healthy plants and they didn’t fry, just weird foxtails, bleaching and nanas.
The RH raising would have been my next question thank you for also answering that lol. So I will also raise the RH a bit too so they have it a little easier. I did that some days ago in attempting to lower the vpd. it helped a little but if the light was still frying them theres no way only that would help lol.

Ok so I will drop the EC. Raise the light. Dim the light. Raise the RH for a few days. And we will see how that goes...

Thank you @ ALL for all your help and input! I will update here to see how that goes! Thanks a lot.
 

RookieMuffin

Well-Known Member
Sounds a plan. I’d be more worried about the EC to be honest. High vpd you want to run less EC because they are feeding harder. Drop it way down to like 1.4, bump the humidity a bit for a few days so they aren’t feeding so hard and see if they start to recover. I’ve run silly high ppfd with healthy plants and they didn’t fry, just weird foxtails, bleaching and nanas.
Lol without adding co2? I think the bleaching and nanas weed is for the trash then?
 

tstick

Well-Known Member
You gotta put yourself on a slower scale of expectations when it comes to plants. You can't keep piling on new things and changing everything around if you're not seeing overnight results. Every time you change something you might as well figure that you will have about a one-week setback before the plants start responding to any changes you have made.

Quite frankly...fuck all this VPD/EC/PPFD stuff -especially for inexperienced growers. It just makes gardening into a mathematics class to have to mix this, measure that, calculate this, etc. If you run a commercial business and have hundreds of plants to manage, etc., then yeah okay.

Keep it simple and slow your rate of expectations down.
 
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