Lets talk VPD in flower

What humidity are you running during flower?

What is the lowest temp you run?

What is the highest humidity you’ve ran until the end of flower and still passed testing or didn’t have any visible bud rot if you didnt test the flower?

I’m usually running (VPD/TEMP) 1.0/82-84f during stretch, 1.2/80-82f-mid, and 1.5-1.6/75-77f by the end of flower. Temps are lights on.

I run same night and day temps for stretch, roughly 5-8f less mid to end of flower. Thoughts?

I appreciate any feedback.


I have messed around with a bunch of different temps.

My favorite temp was 80*f for veg
75 and as low as 60 in flower.

Humidity i try to keep 60- 75% for veg and 50 to 40% for flower no root or anything.

I was getting 2oz for every gallon of soil used. I was growing in fabric pots. Did a variety of sizes

The room was in negative pressure.


@ChrisPotts are you running hid lights? Im running leds

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Old days home indoor grow 70-80 degrees never more then 70%-75% humidity

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Yeah spider farmer leds

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I like to keep plant temps around 80 @ 1-1.2 for veg/prop
Plant temps around 78 @ 1.3+ for flower

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I appreciate all the feedback! Keep em coming.

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Also if you could including what yield per light (16 sq ft) you are achiving with these conditions? Feel free to include any additional info you want to.

Im averaging roughly 2.25-3.25 per light (16 sq ft) depending on genetics using hlg scorpion diablos, ion 720 bar, fluence 2i, hlg diablo. All are capable fixtures.

Roughly 1000-1200 ppfd at the tops depending on which lights

Running c02 @ 1250 ppm

Nutes jacks 321 @ 2-3 ec depending on if im using blumat or dtw in coco

Running 1-3 plants per light in 3-7 gallon pots depending on plant size and number of plants per light.

Disclaimer: im just an amateur sharing some info and seeing what others are doing .YMMV

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