The Importance of Hoods/Covers over Temperature and RH Sensors

[3cats]

There's an app called photone free for Android phones, install it and calibrate it against your light ppfd chart, it's pretty accurate and gets us in the ball park.

Light intensity rules everything else we just can't expect same hps yield giving lower light intensity with LEDs that's a fact.

The most important thing is light intensity, than it's Leaf surface temperature (air temps and RH too), co2, water content/drybacks, rootzone health, wind, nutrients.

and love.

I'm old you speak of things I know nothing about app? android I have a phone on the wall, I think its a Bell.

 

[Trash_2002]

and love.

I'm old you speak of things I know nothing about app? android I have a phone on the wall, I think its a Bell.

I'm in my 40`s but I'm pretty tech savvy tho hehehe do some research around you gonna learn pretty easy about ppfd ;-)

A 600w hps at 50cm with open hood (no glass),will give you around 1000ppfd
Optimum light intensity without co2 enrichment.

A common.645w bar style LEDs at 60cm will.give you around 900-1000ppfd depending on diodes used.

Every manufacturer will give you the ppfd chart for their light at some different distances for reference.

 

[3cats]

I'm in my 40`s but I'm pretty tech savvy tho hehehe do some research around you gonna learn pretty easy about ppfd ;-)

A 600w hps at 50cm with open hood (no glass),will give you around 1000ppfd
Optimum light intensity without co2 enrichment.

A common.645w bar style LEDs at 60cm will.give you around 900-1000ppfd depending on diodes used.

Every manufacturer will give you the ppfd chart for their light at some different distances for reference.

Too many numbers for an old guy , I'll wave my lux meter around and set my lights according to the numbers usually but once I figure I know it all I'm like fk it I'm too good for tools.lol I veg under t5's and only flower under my led's I've 3 se 3000 and an sf600. 2 in my 5x5 1 in my 3x3 and I intend on cutting 1 in half and add it into my 5x5 on both ends of the 2 already there. I've been using the 600 there but its not really a flowering light.

 

[Trash_2002]

Too many numbers for an old guy , I'll wave my lux meter around and set my lights according to the numbers usually but once I figure I know it all I'm like fk it I'm too good for tools.lol I veg under t5's and only flower under my led's I've 3 se 3000 and an sf600. 2 in my 5x5 1 in my 3x3 and I intend on cutting 1 in half and add it into my 5x5 on both ends of the 2 already there. I've been using the 600 there but its not really a flowering light.

SE3000​

you will probably want it at ~30-40cm from the canopy at peak flower to reach around ~750-900ppfd

 

[LoveGrowingIt]

Light isn't the only growth factor that affects yield. My take on optimizing growth is that all the growth factors contribute to optimizing yield and quality. I have been thinking about light, though, except it has been regarding shape of the tent and the positioning of the lights. I've noticed that a single plant grows very well in a square tent. My current theory is that the plant benefits from near equal reflectance off the sides. I have a ViparSpectra XS2000 in that 2x2 tent and probably will replace it for the next grow with an AC Infinity T22.

There's an app called photone free for Android phones, install it and calibrate it against your light ppfd chart, it's pretty accurate and gets us in the ball park.

I have the Photone app, but haven't calibrated it. Using the PPFD chart is a great idea. Do you set the light to 100% to calibrate the app?

I've never been able to run my lights at 100% without cooking the plant. 40% (or 90 watts at the outlet for a light rated at 240 watts) is about the maximum.

 

[Trash_2002]

Light isn't the only growth factor that affects yield. My take on optimizing growth is that all the growth factors contribute to optimizing yield and quality. I have been thinking about light, though, except it has been regarding shape of the tent and the positioning of the lights. I've noticed that a single plant grows very well in a square tent. My current theory is that the plant benefits from near equal reflectance off the sides. I have a ViparSpectra XS2000 in that 2x2 tent and probably will replace it for the next grow with an AC Infinity T22.


I have the Photone app, but haven't calibrated it. Using the PPFD chart is a great idea. Do you set the light to 100% to calibrate the app?

I've never been able to run my lights at 100% without cooking the plant. 40% (or 90 watts at the outlet for a light rated at 240 watts) is about the maximum.

For running higher than 900-1000ppfd co2 is recommended, I also don't go to 100% on my lights, 80% max without co2 (645w flexstar bar lights).

Yes I calibrate it with the lights at 100% at 60cm as my lights chart have the numbers for 24" witch is my target, calibrate it with the tent almost closed for better accuracy.

Yes as I said
"The most important thing is light intensity, than it's Leaf surface temperature (air temps and RH too), co2, water content/drybacks, rootzone health, wind, nutrients."

Light intensity being dialed is the number one factor for yield off course you have to have everything else dialed in following that.
More light at proper LST plants will drink more, eat more, use more co2, open more their stomatas etc etc, photosynthesis and cells expansion happens much faster, when we are pushing to "11" it's trickier too.

 

[LoveGrowingIt]

@Trash_2002 Thanks! I'll add calibrating Photone to my to-do list for between grows.

 

[Trash_2002]

One thing people often don't realize, me included, is that this more modern and accurate sensors with housings and etc, if they are installed without a hood under the lights the readings will be pretty far off from the reality, because of radiant heat coming from the lights heating the carcass and throwing off our readings over time.
View attachment 2039413View attachment 2039414View attachment 2039415
Without the hoods temperatures in f1 and f2 tents get to 29.5c , 3 degrees celcius off from the reality also RH will be much lower without the hood ( almost 8% lower without the hoods in my case), the effects are instantaneous and pretty severe.


This old school probes sensors, they have a different approach with the probe witch doesn't get too much heated with radiation, the area to heat is much smaller and usually its in the vertical position
but its still off by at least +1c then it should.
Now the reading from the internal unit (not the probe), will have the same effect, plastic will absorb heat and throw off temp and RH readings
View attachment 2039412


Jerry rig some hoods on your sensors, you will get much more accurate readings this way.
Cheers!

How Do You Measure Air Temperature Accurately?

To get an accurate reading, it’s important to avoid heat from the Sun.

www.nist.gov

Good read on measuring air temperature ;-)