VPD, temp and Humidity using quantum boards during veg and flower.

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Tommy_Green

Tommy_Green

14
3
Hi all,

I'm a noob and on the first grow. It's been a great journey so far. Can't believe how much I love it! I'm amazed at how much there is to learn and constantly checking what info I'm using is right and relevant for me.

I recently got 2 x Quantum 480 watt boards with no IR or UV just the 600 nm diodes. They are Bright!!!!

I was following old school HID guides for temp and Humidity. I was growing with 2 x HID 400's and one small 250 HPS while waiting for the LED's to arrive. It's far brighter but not much less power usage.

Recently I came across VPD. I've been referring to the the https://docs.google.com/spreadsheet...q_6Mkpd3yJwedSZ3kfxuK0ZVI/edit#gid=1898379675

I've been following some tips from spectrum king vids which have been interesting.

Currently my simple smart humidity and temp sensor is saying 27 C and 70 humidity. Giving me a VPD of 1.3 - I was previously at a higher Humidity but was concerned about being too hot and and humid when referring to tips from grower without LED's. According to the chart increased Humidity will bring me back to VPD of 1 which I believe is to be the ideal for veg for LED? I've been searching for some solid referneces but seeing these boards are pretty new... Maybe that's why it's hard to find.

I've got an infrared laser gun coming to measure the leaves and parts of the tent to fine tune but love to know what works with these lights if anyone is able to chime in. Not having IR and UV atm (may look for some additional bulbs that can add that spectrum soon. But no IR means less heat.

Any tips on what to use for additional IR and UV? I may be getting a loan of an HMS to throw in during flowering. I opted to not have the IR and UV diodes added as they seemed more of a gimmick, especially the UV ones. I worked with UV photography and you need a lot for it do anything. Whether the small amount of UV from 8 diodes would add something is yet to be proven.

So currenlty what are people finding with these Boards? What's a good VPD, temp and Humidity for Veg and for flower? What leaf temp can I have and do I use that to determine how close I can have the lights to the canopy?

I'm doing a DTW, in coco and perlite and it's in a 4 x 8 tent. Watering with halo's every 3 hrs.

I'm not using C02 atm but am pumping in a heap of clean air into the room that houses the tent. Need to invest into a good c02 meter next grow....

I'm organising dehumidifiers atm to help control the humidity, especially for the flower stage. Borrowing a unit to dry the main room to see what that does but thinking I'll just get small quite unit in the tent as I'm after a quite environment once dialed in.

Cheers!!!!
 
threatco

threatco

594
93
Hi all,

I'm a noob and on the first grow. It's been a great journey so far. Can't believe how much I love it! I'm amazed at how much there is to learn and constantly checking what info I'm using is right and relevant for me.

I recently got 2 x Quantum 480 watt boards with no IR or UV just the 600 nm diodes. They are Bright!!!!

I was following old school HID guides for temp and Humidity. I was growing with 2 x HID 400's and one small 250 HPS while waiting for the LED's to arrive. It's far brighter but not much less power usage.

Recently I came across VPD. I've been referring to the the https://docs.google.com/spreadsheet...q_6Mkpd3yJwedSZ3kfxuK0ZVI/edit#gid=1898379675

I've been following some tips from spectrum king vids which have been interesting.

Currently my simple smart humidity and temp sensor is saying 27 C and 70 humidity. Giving me a VPD of 1.3 - I was previously at a higher Humidity but was concerned about being too hot and and humid when referring to tips from grower without LED's. According to the chart increased Humidity will bring me back to VPD of 1 which I believe is to be the ideal for veg for LED? I've been searching for some solid referneces but seeing these boards are pretty new... Maybe that's why it's hard to find.

I've got an infrared laser gun coming to measure the leaves and parts of the tent to fine tune but love to know what works with these lights if anyone is able to chime in. Not having IR and UV atm (may look for some additional bulbs that can add that spectrum soon. But no IR means less heat.

Any tips on what to use for additional IR and UV? I may be getting a loan of an HMS to throw in during flowering. I opted to not have the IR and UV diodes added as they seemed more of a gimmick, especially the UV ones. I worked with UV photography and you need a lot for it do anything. Whether the small amount of UV from 8 diodes would add something is yet to be proven.

So currenlty what are people finding with these Boards? What's a good VPD, temp and Humidity for Veg and for flower? What leaf temp can I have and do I use that to determine how close I can have the lights to the canopy?

I'm doing a DTW, in coco and perlite and it's in a 4 x 8 tent. Watering with halo's every 3 hrs.

I'm not using C02 atm but am pumping in a heap of clean air into the room that houses the tent. Need to invest into a good c02 meter next grow....

I'm organising dehumidifiers atm to help control the humidity, especially for the flower stage. Borrowing a unit to dry the main room to see what that does but thinking I'll just get small quite unit in the tent as I'm after a quite environment once dialed in.

Cheers!!!!

Hello,

Sounds like you are on the right track.

The laser temp gun is helpful for getting an idea of the difference in the leaf surface temp, and the nearby air temp. In practice I find I don't need to use it a lot. My leaves are always 2c cooler than the air as long as VPD is in a good range and the lights are not too close. So I don't check that every day, more once in a while just to confirm it's still right.

With that in mind, I will link the chart I use. Same thing, but maybe a little easier on the eyes, and it's for 2c difference.



1591992983958



Since I have been following this chart, I have noticed much happier plants.

My veg chamber stays between 28-31c, which I simply offset by keeping the humidity in there around 70%.

The risk of keeping it hot and humid is the chance of mold etc... But in my situation, the area is very clean and so far never been an issue.

My flowering tent stays around 24c, so my normal local humidity of 35-50 works fine.

It is handy being able to adjust the humidity in response to temperature, rather than always trying to keep the temp at a sweet spot.





On to the IR + UV debate.

I think it can be generally accepted that IR is more proved than UV to be beneficial.

My research and my own experience leads me to believe having some IR is critical to putting photoperiod plants to bed "quicker"

Watching my plants on timelapse, they know when it is almost bedtime and will sag 1 hour before lights out regardless of the environment. If I didn't have IR they would take an hour + in dark to go to sleep.

In my opinion, this allows for cycles like 13/11, and maybe more tolerance to things like light leaks.

UV, well a lot of people don't believe in LEDs being effective here. I am in the camp of "it's only 4 led's per board, just put them on there, it won't hurt".

But I do understand the argument to be made. If you want UV, you would go UVB from a fluorescent source. But practically speaking, who wants to wire and position a bunch of those in the grow space for coverage?

Not me.

I think so much is strain dependant that it is hard to get a concrete answer on the best approach.
 
Tommy_Green

Tommy_Green

14
3
Thanks @threatco for all the info! That chart helps a lot and gives me a better idea about VPD

I'm struggling atm to get the humidity down, having to do it via temperature control which sometimes means less fresh air. I'm flying blind with no C02 sensor either. Looking forward to know what I'm working with there too.

I'm looking into getting some small dehumidifiers. https://www.amazon.com.au/Dehumidif...2DB5HK1Y1PG&psc=1&refRID=PPHP332E62DB5HK1Y1PG

I'm hoping I can rig a wast pipe to it and just smart control it. I'm after a relatively quite operation and also these don't use much power.

How far do you have your boards from the plants generally? Atm I'm about 40-50 cm's. (need that infared laser gun!)

I wish I got the IR now.... I was considering to have them do IR instead of UV and IR. Hopefully I find a solution that works. I wanna see the difference now by having it.
 
threatco

threatco

594
93
Thanks @threatco for all the info! That chart helps a lot and gives me a better idea about VPD

I'm struggling atm to get the humidity down, having to do it via temperature control which sometimes means less fresh air. I'm flying blind with no C02 sensor either. Looking forward to know what I'm working with there too.

I'm looking into getting some small dehumidifiers. https://www.amazon.com.au/Dehumidif...2DB5HK1Y1PG&psc=1&refRID=PPHP332E62DB5HK1Y1PG

I'm hoping I can rig a wast pipe to it and just smart control it. I'm after a relatively quite operation and also these don't use much power.

How far do you have your boards from the plants generally? Atm I'm about 40-50 cm's. (need that infared laser gun!)

I wish I got the IR now.... I was considering to have them do IR instead of UV and IR. Hopefully I find a solution that works. I wanna see the difference now by having it.

Glad it was helpful.

A dehumidifier might be needed.

But some other options include increasing airflow with more CFM ventilation power.

More circulating fans.

Defoliation of the lower third.

Added benefit more co2 to the stoma that need it, while humidity goes down.

I hate taking up floor space, so depending on the situation, I might consider some of these options.
 
Tommy_Green

Tommy_Green

14
3
Very good point. Need to work on my CFM.

I'll now reposition my fans inside on high, currently have them on the plants to keep them swaying but see if I can play with position to get more movement of air and still have some sway. I probably need one more fan too.

I was hoping that my outake iso fan would be creating enough negative air pressure but perhaps not. Trying to work out if I need an intake fan (more noise). I did do this initially but it was creating positive pressure and therefore making things a bit smelly. A mate has told me about some quite low powered fans that could help insuring FAE is achieved. *Again need CO2 sensor but a drop in RH should indicate it's working providing the air outside the tent is lower than the tent. I have two temp and humidity sensors. My outside room is still pretty humid.

I'm also working on making sure my outside room has positive pressure.

Hopefully all these little tweaks means I can get away with those little dehumidifiers for final tweaks.

Lights off is when I get a massive rise in Humidity, still trying to work out how to combat that. Hoping better CFM inside and higher outside positive pressure with lower humidity will do the trick?
 
threatco

threatco

594
93
Very good point. Need to work on my CFM.

I'll now reposition my fans inside on high, currently have them on the plants to keep them swaying but see if I can play with position to get more movement of air and still have some sway. I probably need one more fan too.

I was hoping that my outake iso fan would be creating enough negative air pressure but perhaps not. Trying to work out if I need an intake fan (more noise). I did do this initially but it was creating positive pressure and therefore making things a bit smelly. A mate has told me about some quite low powered fans that could help insuring FAE is achieved. *Again need CO2 sensor but a drop in RH should indicate it's working providing the air outside the tent is lower than the tent. I have two temp and humidity sensors. My outside room is still pretty humid.

I'm also working on making sure my outside room has positive pressure.

Hopefully all these little tweaks means I can get away with those little dehumidifiers for final tweaks.

Lights off is when I get a massive rise in Humidity, still trying to work out how to combat that. Hoping better CFM inside and higher outside positive pressure with lower humidity will do the trick?

If you can't beat down the humidity, you could just up the temperature instead, if that is easier.

It will both lower humidity by increasing it's capacity to hold moisture, and will increase the plants tolerance to high humidity.
 
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