Temps with laser temp gun

[westpoint]

My ac infinity digital temp guage is reading 81f right next to seedlings. My laser temp gun is reading 74f on my seedlings leaf. What do I go off of? Thanks.

 

[J232]

Lst will be lower then ambient with led and higher with hid, how much can vary. Go with laser on the leaf imo.

 

[Jjgrow420]

That ^^

 

[calvin.m16]

Depends what you're referencing. Air Temperature is different than Leaf Surface Temperature (LST). LST goes with VPD calculations.

The Ultimate Vapor Pressure Deficit (VPD) Guide

"Why devote an entire guide to VPD?" you might ask. The answer is that the vapor pressure deficit (VPD) is extremely important for growing plants. VPD helps you identify the correct range of temperature and humidity to aim for in your grow space. With VPD you can achieve the best results while...

pulsegrow.com

 

[blueberrymilkshake]

Depends what you're referencing. Air Temperature is different than Leaf Surface Temperature (LST). LST goes with VPD calculations.

The Ultimate Vapor Pressure Deficit (VPD) Guide

"Why devote an entire guide to VPD?" you might ask. The answer is that the vapor pressure deficit (VPD) is extremely important for growing plants. VPD helps you identify the correct range of temperature and humidity to aim for in your grow space. With VPD you can achieve the best results while...

pulsegrow.com

Everytime I log on I get homework

Brb

Edit: some of the article's comments are interesting lol

 

[Jjgrow420]

Vpd. Lol

 

[DrOgkush]

Lst. Think of yourself in the Sun on high uv index days vs low days. Cooler temps. But hotter to the skin. Your vpd is like for example Florida humidity and heat. Feels a lot worse than it really is. 80 feels like a 100. But in California temps are identical but with much less humidity and 80 degrees feels amazing.
Kinda similar if you relate it towards plants. The lst is very important. Your humidity/IR/energy all affect your LST

 

[calvin.m16]

Lst. Think of yourself in the Sun on high uv index days vs low days. Cooler temps. But hotter to the skin. Your vpd is like for example Florida humidity and heat. Feels a lot worse than it really is. 80 feels like a 100. But in California temps are identical but with much less humidity and 80 degrees feels amazing.
Kinda similar if you relate it towards plants. The lst is very important. Your humidity/IR/energy all affect your LST

I've found airflow plays a huge role in Leaf Surface Temperature too. Not enough airflow especially on the top of the canopy can cause some buds/leaves to get mighty hot especially under 1000w DE HPS..

 

[DrOgkush]

I've found airflow plays a huge role in Leaf Surface Temperature too. Not enough airflow especially on the top of the canopy can cause some buds/leaves to get mighty hot especially under 1000w DE HPS..

Yes. I didn even mention that.

 

[westpoint]

Just seems like it a 9 degree difference sometimes. So as long as my leaf temp stays under 80 im good? What if room temp is 90? Just a example.

 

[DrOgkush]

Just seems like it a 9 degree difference sometimes. So as long as my leaf temp stays under 80 im good? What if room temp is 90? Just a example.

Your lst is under 80 with an ambient air temp of over 90F ?

 

[calvin.m16]

Just seems like it a 9 degree difference sometimes. So as long as my leaf temp stays under 80 im good? What if room temp is 90? Just a example.

You want to keep your leaf surface temperature below 80 to be safe.. You can push it but every plant is different. A happy Air Temp or LST for all cannabis plants is 75 °F lights on 68 °F lights off veg or bloom in my personal experiences with LED , Fluorescent and HPS grow rooms..

 

[westpoint]

Your lst is under 80 with an ambient air temp of over 90F ?

No tent tent is 83, leaf temp 71.