Possible light issue?

DirtyDogs446

Well-Known Member
They seem to be overwatered from the RH
High RH needs high heat and high light intensity coupled in order to achieve optimal growth rates.
Make sure you are optimal not in the VPD chart, but in terms of phase of growth, you can start pushing them now as they have some leaf to absorb.
At this stage I set RH to 70-80%
And temp to 29-31c.
Intensity of lights always 100% but I use HIDs so in leds this might be different as different boards and diodes have different impacts at this and that heights and intensity.
Yesterday I turned down the rh and raised temp slightly today they are perky thank you for all the info1000002836.jpg
 

DanKiller

Well-Known Member
Yesterday I turned down the rh and raised temp slightly today they are perky thank you for all the infoView attachment 5370511
Indeed looking better, don't give any nutes now, it seems like it's messing with your medium balance a bit.
Remember, aside from VPD, which shows you what temp is good for what rh and the opposite, all plants grow better if you give them better conditions.
People post VPD but they don't understand that optimum conditions are constant, and according to the VPD charts, I can grow them at 20c with low rh and my VPD will be considered good, but it won't make them grow better or faster.
The rules of the jungle are simple
Things grow faster and better with high heat high humidity.
 

Delps8

Well-Known Member
With using the app on my phone and comparing it to what the manufacturer has said the ppf should be at what distance it is very very close. I moved the light high as it could go yesterday haven't been home sense today I will go over the vpd scale you gave me
Good to hear! That's a great way to get things dialed in.

Now that the issue has been diagnosed as a nutrient issue, how about giving your plants more food?

Re. "very very close" - is "good enough". The goal is to get the grower in the ballpark and then they can adjust as needed. An Apogee is calibrated to 5%±. A light meter+conversion factor (which is how Photone works) may be a more inaccurate because there's 5%±, in the case of the Uni-T, as well as, perhaps, the conversion factor being off. But that's fine because even if it's, say, 10% off, that's only 100µmol at high light levels.

I usually take light readings daily and, with the plant at it's current size of about 2' x 2' x8", I take nine samples.

These data are from yesterday. It's a Growcraft X3 at 292 watts. The plant is in day 44 and the schedule is 24/0. The canopy looks level but, looking at the numbers, it looks like the light is crooked and/or the canopy is lower in the back left and rises to front. And there's a difference of 150µmol± between those two spots.

It's like raising kids - just give them the best conditions you can and watch them grow.

1708012867531.png

Now that I think about it a bit, we do vivisect them and then burn them so perhaps the "kids" analogy isn't quite right…
 

Phytoplankton

Well-Known Member
I don't see a darn thing wrong with them. Let them adjust to their new home, they'll be fine. VPD is vastly overrated IMHO, look at outdoor plants, the VPD swings wildly and they do just fine.
 

Phytoplankton

Well-Known Member
Boron shortage. Should get better with root growth, your plants were real close to topping themselves though.
A Boron shortage in HF soil is highly unlikely, in fact any commercial soil should be fine. Happy frog doesn't have nearly as much NPK as FFOF, so after about 2 weeks you'll need to start a nute regime. .
 

Delps8

Well-Known Member
VPD out of range can cause significant issues. This YT video might provide insight.

One key issue is that as transpiration increases, water uptake increases and, in turn, the amount of nutrients in the plant increases and that can lead to nutrient imbalances. The plant will keep the same % of water, over time (it has to or it would burst), the primary mechanism being by opening the stomata and allowing the water to escape. That helps cool that plant.

But what happens to the chemicals that came in with the water? If it can't use them quickly enough, that will tend to create an imbalance. Perhaps that's what happened here?
 

DanKiller

Well-Known Member
VPD out of range can cause significant issues. This YT video might provide insight.

One key issue is that as transpiration increases, water uptake increases and, in turn, the amount of nutrients in the plant increases and that can lead to nutrient imbalances. The plant will keep the same % of water, over time (it has to or it would burst), the primary mechanism being by opening the stomata and allowing the water to escape. That helps cool that plant.

But what happens to the chemicals that came in with the water? If it can't use them quickly enough, that will tend to create an imbalance. Perhaps that's what happened here?
You can be outside VPD as long as you keep basic rules in veg / flower.
Like @Phytoplankton said, VPD is overrated as it confusing growers.
Look at nature and you will understand everything, the hot humid amazon jungle for veg, and the cold, low humid of malana mountains for flowering ;)
But in reality we want yield aswell as density and other stuff that heat and rh contribute to.
So it should be more balanced at flowering especially as it's the crunch time, both for budding and trichomes (quality).
 

Hollatchaboy

Well-Known Member
Vpd can be a limiting factor. Sure you can absolutely grow good weed outside the optimal vpd range, but....... could it of been better had it been grown within range?

A plant is going to express its traits best, when all it's demands are met.
 

DirtyDogs446

Well-Known Member
I don't see a darn thing wrong with them. Let them adjust to their new home, they'll be fine. VPD is vastly overrated IMHO, look at outdoor plants, the VPD swings wildly and they do just fine.
When I started growing in 2018 I never even heard of vpd now it's a thing lol but I am trying to be in decent range now that I know they are looking good now just needed to adjust
 

Cboat38

Well-Known Member
FFHF doesn't need any nutes at this point. Water only for now.
I was hoping someone would say that, the op is doing too much for it be a seedling. You got to keep it simple that soil has enough nutrients in it to last until it’s first transplant, shit I use fox farm soil and I don’t top dress until I see my first stigmas lol…. but for real
 
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