What numbers does everyone keep for vpd during flower

So beautiful @BigCat420 hopefully mine is up to that standard.

I smoke for ptsd so that’s great to hear!

Feel free to follow my post if you’d like. I strongly suggest looking into hellraisers posts. Even tho he is no longer on the forum he still has a lot of knowledge that can be absorbed by others and shared to help others

I usually don’t like pure sativas as they give me anxiety so that’s why I’m only growing 1 plant so I can see how I like it . I actually got them free with my order from ethos getting end game seeds from North Atlantic seed co, I got mandarin cookies free as well . They are m/f so hopefully those are female. The green crack is feminizd

Absolutely I’m trying to get my skills on lock. I look through old post to learn . I’m def following your stuff, that’s why I tag you in most of my questions . Love what your doing @BigCat420 !

@matty777 thanks man i really appreciate that! I love growing and i love helping people. I truly enjoy helping others solve their problems because for all i know it could be something i run into down the road and then i know how to deal with it and relay that info to others so we can keep it going full circle! Love this forum, the people on it, and just glad i can do what i love and continue to learn more while helping others!

Well said. What he said… :point_up_2::+1:t2::v::sunglasses:

I’m right there with you. I tried keeping VPD dialed in perfectly for a minute. What I found was that when temperature and humidity are in the commonly accepted ranges for veg or flowering the vpd is in recommend range or close enough. My lights on temp gets a little hotter sometimes, but my numbers are basically right there with yours. Amazing what proper airflow can do for a grow. Exhaust fan wide open, two small fans blowing up between the plants and an oscillating fan on one side gives plenty of airflow for my 2x4. I have another ac infinity oscillating fan still in the box if I decide I need more airflow.

Exactly… what he said!

I feel the same way and am grateful for this forum, like I said it’s a good time to learn to grow .



Should I defoliate more? What’s everyone think?


Beneath the canopy

I just don’t want to overdo it .

Day 21 and 42 is defoliation days if your following that schedule. If it were me id pluck a couple of the bigger fan leaves up top so your bud sites can get more light other than that your plants look great brother!

Thanks man!

Thats exactly what I thought as well

No problem! Glad to help!

Great read !

Look at the Leaf VPD target ranges in the top right corner of the dimlux charts.

One thing to know about the static charts is that each one only covers one offset value/ the difference between the leaf temp & the air temp. You could be looking at a 0f offset chart or a -20f offset chart when you need a -5f offset chart. If your chart offset doesn’t match your actual offset, then it is not giving you your Leaf VPD numbers. Subtract air temp from leaf temp to get your offset. Then you can pick the right chart. I would also suggest checking the offset after that to see if you need to move to different charts along the way.

I use an IR temp gun for leaf temps. Quickly I found charts to be slow & a pain to use, so I use a calculator that lets me enter in my air temp, leaf temp & RH to find Leaf VPD. Also makes it a lot easier to see how changes affect the Leaf VPD number.
Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights

  • Calculator says 1.13kpa Room VPD using 70f & 55% RH, so something seems off there. How are you getting your number?

  • If you are trying to hit Leaf VPD targets using only air temp & RH to get a VPD number, then that is not what you want to be doing. You’ll end up tuning your Room VPD, & most likely your Leaf VPD (the real target) will end up being way off.

:point_up_2: I see I’m not the only one. As long as I keep 76-80/60% in veg and 70-78/50% in flower seems to work for me :love_you_gesture: