The Gee Spot - You Finally Found It

[Gee64]

Here are my current numbers. Warm, moist, and low enough light that the little rootballs can keep up. 6 degrees of difference. As they grow taller they will get closer to the light and leaf temp will rise.

Once they start to take off I will slowly increase light intensity until I get a 2 degree difference, but it may take me 3 weeks or more to get there. Right now they need to grow roots, not leaves. In 6 more weeks they will be tall enough for flower for sure, and maybe too tall, so I'm in no hurry to grow anything but roots.

 

[Gee64]

@Thirvnrob I want to show you a 2 part scenario, to emphasize why you should only make adjustments later in the day.

Lets say at 10 hours in you have this, and you are 5 weeks into flower. Things are perfect. Then tomorrow you wake up and run to the grow and do a check at hour 1, and you see this

The tent got colder overnight as it always does, so the plant raised it's temperature to keep it's vpd almost exactly the same.

If all you saw was a leaf hotter than the air, your reaction would be to panic and turn the light down, but as the day goes on it will steadily improve back to picture 1. Air temps will rise, transpiration will restart, and leaf temps will cool.

The target of 1.4 is the target of the fastest time of the day. Not the target to run at all day long. So you react to things after 10 hours or so. Make sense? This is really important or you can screw them up.

 

[Thirvnrob]

I don't mind at all, go grab a coffee

VPD works best when leaf temp is 2 degrees cooler than the air. Thats the temp differential that transpiration transpires best at. Vpd should also never be run higher than the stage the plant is at. The stage the plant is at is dictated primarily by how well the rootball can supply the plant with food and water.

So when you adjust vpd, never run it high enough to cause the plant to run faster than the rootball can handle. That part is on you to determine, so slow and steady until you start to reach a limit is best. Big adjustments will bite you.

If you go faster than the rootball can handle you get an instant deficiency because you are photosynthesizing faster than the rootball can provide the photosynthesis department, so the photosynthesis department, instead of slowing down, starts drawing nutes from the leaves. Fry them and the grow is in trouble.

I give you all this warning 1st because light is what primarily determines the difference in temp between the leaves and the air. You DO NOT want to give your plant too much light ever, unless you are in the last 2 weeks of the grow where hermies can't hurt you. Light is the easiest tool to use to cause hermies.

So for you at 81F air, 78F leaf, and 65%RH, the easiest way to raise vpd is to lower humidity but..... A 2 degree difference would be nice too. So if your plants are still getting taller I would live with the 3 degree difference and the plant will grow into the light and it will move to a 2 degree gap. After that you may have to either raise the light or turn it down a bit.

If stretch is over I would turn up the light a little bit. Sometimes 50ppfd more is enough. Then wait until 10 hours of lights on tomorrow to assess the adjustment and react to that. Not before unless you see danger.

Then once the 2 degree dif is established I would lower RH to increase vpd and as flower progresses I would lower the air temp as well, all slowly and incrementally to make sure you never run the plant too fast for the rootball. I try never to go over 1.45, even in deep flower. One glitch and it could over rev and fry leaves or cause hermies.

If you get to 76F air, 74F leaf temp, and 48RH, your vpd is 1.4 which is perfect, and you aren't at risk of mildews and rot.

Check vpd any time you like, but never adjust unless the lights have been on for 9 or 10 hours. You want to know how fast they are running when going top speed.

If you speed them up in the morning, they may over rev in the afternoon.

Checking vpd at various times of day is pretty cool. You see what happens when you water. You see what state they are in when they 1st wake up. You see what state they are in when they are thirsty.

If your leaves mysteriously get hot, she probably needs a drink. Check that before you turn the lights down. If she is running slow chances are you just finished watering, that sort of thing.

Then when you learn the plants cycles you see advantageous and disadvantageous times of day to give water, or to prune.

Why water or prune when she's running hard. Why not water or prune when she's running slow in the morning.

Now when you have her running properly AND your not interupting her during peak work hours, she can photosynthesize more in a day. That right there is your target.

So if you make an adjustment and she stresses, you have reached a limit. You need to wait for the rootball to catch up, or you have simply found the genetic limits.

Please try not to run her right on the edge. You only need to be in the ballpark. If you can keep her in the ballpark for the entire duration of flower, you will have amazing colas. If you over rev her once you will lose far more than that little extra you were trying to squeeze out.

The state of your rootball just got more valuable. You can't use more light if the rootball can't supply. Make sure it's NEVER the weakest link and you will need extra jars for harvest.

Are you in flower? If so, how far in? Got some pics?

Day 46 of veg. Flipping in two weeks.

 

[Gee64]

Nice! Are those Sips? Organic or synthetics?

 

[Thirvnrob]

Three 10 gallon sips & one 5 gallon, all LOS. I was supposed to compare one of each in my own (The Rev's) mix vs. a store bought LOS, but I had a brain fade & planted both double Chocolate (on the right) in my mix & both Acapulco gold in the store bought mix. I really regret that mistake based on the difference between the two. I don't know if its soil or genetics that's responsible for the difference in size...

 

[Gee64]

Day 46 of veg. Flipping in two weeks.

Sweet!
I know AG is a sativa but I'm not sure about the Double Chocolate. It looks skookum though. Does it have kush genetics? That could explain it's stout size/shape.

How are you finding Los and SIP's working together? Have you harvested a LOS SIP grow yet?

 

[Gee64]

Maybe I need a different gun. I don't see how it could measure RH...

as long as it gives you a leaf temp, thats all you need from it. Your weather station supplies the rest. The app will do the math for you.

 

[Gee64]

Here is my ideal vpd targets. I say ideal because every day is different, but you need to stay in the ballpark.

Today is a good example of that. I should be at 75F,73F,65RH but we have El Nino screwing with our weather and it's much warmer than usual, so I need to compensate for that, and I transplanted yesterday so I need to compensate for that.

So I am dealing with heat, which means lower RH, and I transplanted so I lowered the light a bit for a few days to let the transplant settle but I still want a .85 value if I can get it, so I went 79F,73F,60RH.

79F is due to crazy ambient temps, 73F is me lowering the light until the leaf temp worked in the formula, and 60RH is what I am stuck with until the weather straightens itself out.

So 79F,73F,60RH=.74 which is a bit low, but the transplant needs that for 2 or 3 days, so it worked out pretty well.

Once I see vigor I will adjust to get back on target. 77F,75F,65RH is target in a week but with the transplanting I won't force them there until they are ready. Once they get established it will be pretty easy to get them back on target

So in a perfect world, here is my VPD schedule. No date means a mid-week adjustment.

When they are young I don't stress if I can't get the 2 degree difference, its the VPD value I want, so you can compensate by adjusting air temp and/or RH to get your value.

If your target is far away DO NOT try to get there in a day. Make adjustments every 3 or 4 days and if you need to move 2 RH points instead of 1, or move air temp 2 degrees instead of 1, catch up that way over the course of a couple weeks. As long as you have a solid 2 degree diff in the last week of veg so you are ready for the demands of stretch. You are good.

If leaf tips start serrating and your numbers are good, chances are your fan is too high causing excessive transpiration.

As your VPD value climbs you should also see an increase in water needs. So be ready for that. So you don't need your light on high enough for a 2 degree difference until they are really growing strong, so be careful with the light settings.

As the plant grows, light will be adjusted almost daily, but in very small increments. Don't overlight what the rootball can handle. Light is for flower time when the rootball is adequate.

Think of your VPD value as suction, because thats what it is. The dry atmosphere sucks moisture from the ground and thru the plant until it exits out the stomata, bringing food with it. Light intensity needs to match this so all the food gets used. A 2 degree difference between leaf and air temps is the ideal difference for maximum transpiration.

Sucking too hard sounds like trying to drink the last half inch of a milkshake thru a straw. That noise is a deficiency at the weakest link, which is usually rootball adequacy.

Dec29 - Day9
73F,71F,65RH=0.79kPa
+1F=.82
+1F=.85 Jan 5 75F,73F,65RH
+1F=.87
+1F=.90 Jan 12 77F,75F,65RH
+1F=.94
+1F=.97 Jan 19 79F,77F,65RH Jan 19
-1RH=1.00 64RH
-1RH=1.04 63RH Jan 26
-1RH=1.07 62RH
-1RH=1.1 61RH Feb 02
-1RH=1.14 60RH
-1RH=1.17 59RH Feb09
-1RH=1.21 58RH Day56 Feb 14 FLIP
-1RH=1.24 57RH Feb21
-1RH=1.27 56RH Feb28
-1RH=1.31 55RH Mar06
-1RH=1.34 54RHMar13
-1RH=1.37 53RH Mar20
-1RH=1.41 52RH Mar27
-1RH=1.39 78F,76F,51RH Apr03
-1F,-2RH=1.41 77F,75F,49RH Apr10
-1F,-1RH=1.40 76F,74F,48RH Apr17
Apr24 Harvest

These are targets, but if I miss I won't stress the plant out too much trying to get back on track, I will adjust the plan and get them there in a week or so. Once you are in flower, maintaining ideal VPD becomes much more profitable. Having the roots and the environment ready for flip should be your real target. If the roots aren't ready, veg longer or be happy with a less than ideal harvest, but trying to force them to comply too quickly will cause grief.

 

[Carmen Ray]

vpdvpd

 

[Wastei]

How about a small camping stove? I have one that takes small twigs, pine cones, can operate on alcohol, etc. Puts out a wicked flame in the footprint of a coffee mug. You'd have to make it in smaller batches of say 1-2 gallons, but still doable. That's the sized batch I make.

I would personally just buy pure leonardite with 50% humic acid, the rest is typically carbon. If you want to save time and add both humates and carbon to your worm farm that is. Easily done and adds more positive input than straight carbon.

My two cents! Cheers!

 

[Azimuth]

I would personally just buy pure leonardite with 50% humic acid, the rest is typically carbon. If you want to save time and add both humates and carbon to your worm farm that is. Easily done and adds more positive input than straight carbon.

My two cents! Cheers!

What size particles is the Leonardite?

 

[Gee64]

TMSC - Day 17.

Wild Lady, in the center, has responded really well. She was stripped to bare roots and strapped down yesterday, and didn't flinch. All her branches have pointed upwards already and no wilting. Tough Gal.

Her clones are doing fine as well. The whorly in the bottom left is cool, I hope it roots .

The temperature probe for the heat mat under the cloner goes in here.

The ambient temp is actually a bit warmer at 77.3F, so the heat mat is off, but the heat mat will kick in during lights out when temps drop.

So now we wait. And hope. And test Durban Doobies like crazy, in the name of science of course .

Only 115 days to harvest, what could go wrong?

 

[StoneOtter]

I'm a whorly fan! They're special plants!

 

[Azimuth]

Wild Lady, in the center, has responded really well. She was stripped to bare roots and strapped down yesterday, and didn't flinch. All her branches have pointed upwards already and no wilting. Tough Gal.

Sounds like maybe she liked it.

Spicy!

 

[Gee64]

Sounds like maybe she liked it.

Spicy!

Hence the "Wild Lady" ...but still a Lady nontheless

 

[Scottay]

Thanks for sharing this info Gee. Rabbit hole stuff for me definitely!! Thanks for the above laugh too!! Gotta love hardcore plant porn right!?!?

 

[Gee64]

Is it really porn if the plant is an exhibitiinist?

 

[Gee64]

Thanks for sharing this info Gee. Rabbit hole stuff for me definitely!! Thanks for the above laugh too!! Gotta love hardcore plant porn right!?!?

Is it really porn if the plant is an exhibitiinist?

 

[Gee64]

TMSC - Day 18.

Everyone is doing well. I gave everyone a drink of fish ferts.

Day 2 for the clones and they still seem happy. No wilting.

They are fairly large cuts. 7" above the cloner, and 3" hanging below. This is one of the clone branch tops.

Here is the other.

Here's the triple.

And the double.

 

[Gee64]

The revegging begins. New green growth is pushing through the flowers.

Green bits poking out everywhere.

Both plants are starting to veg.

Here is the myco farm I started. It's used durban soil from the recent harvest, with dry basmati rice covering the surface, all sprayed moist in a tub, with a cover over it to keep it dark. It's about a week old.