Beeswings
Well-Known Member
But if you raise temps and raise humidity to match, VPD lowers....
Every Plant In Flowering Room Changed Smell
- Thread starter rockso15
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Hollatchaboy
Well-Known Member
That's a good thing. Iirc, it should be between 0.8-1.2, depending on where in the cycle the plant is at.
Beeswings
Well-Known Member
I actually worded it backwards lol but yeah somewhere around 1 is decent for veg and a little higher in flower.
rockso15
Member
So is rhe RH reading true or not? Do I need to figure out how miuch should I increase RH according to the temps? But if the rule of rhe thunb for flowering room is 18-26c and 40-50% RH how do I know if my VPD is off. Or are you telling me my humidity should oscilate with fhis 18-26c, if I understand correct only if my temps are identical at all times (i.e. with an AC) should I have my RH fhe same?I'm not real sure how I should explain it. If you like reading you could check this out.
But most seed companies and grow tent or accessories companies have articles that touch on VPD as well. Humidity measurements are relative to temperatures and if you increase temp you need to increase the relative humidity to maintain the same VPD. The stomata are like pores in the leaves that they breathe and transpire through. When it's too dry and to hot the stomata close up to try and conserve water so not to dry out and kill the plant right away. One biological function that indoor cannabis growers will benefit from knowing just a little about it.
Understanding VPD and Transpiration Rates for Cannabis Cultivation Operations
This article explores how vapor pressure differentials (VPD) affect transpiration rates in cannabis plants. Understanding of VPD at different temperatures and relative humidities, and its effect on this process, is important to gain maximum plant growth.www.cannabissciencetech.com
rockso15
Member
I will try to read into it, I am really too low on time to catch all the ropes with growing atm, forum is very helpful tho
UnknownRemedy
Well-Known Member
That rule came from a time when vpd wasn't really a well known thing. With a temp of 78f/28c and 50% rh you get a vpd around 1.6. You want your vpd to be somewhere around 0.8-1 kPa for a seedling, 1-1.2kPa in veg, and 1.2-1.4 kPa in flower.
Pulse has a vpd guide that should help you understand.
Hollatchaboy
Well-Known Member
Vpd is hard to maintain, without automation. I use ac infinity fans, and humidifier. Keeps my tent in vpd range 24/7, lights on and lights off.
Veg.
Flower
rockso15
Member
Thanks for the info, this is my first serious attempt to gro so I am currently very happy that I even managed to set up all the basics (you remeber the feeling I bet) but this is the piece of puzzle that I will not forget as my goal was hydro and automated setup in the future, but I was thinking soil is best for a newb. How much does the whole infinity setup go?
rockso15
Member
Thanks bro I will read into the pulse guide, really just starting so its all a bit too much but I will get there
Hollatchaboy
Well-Known Member
Depends on your grow space. I have 2 cloudline t6 fans (1 intake, 1 exhaust) and a cloudforge t7 humidifier. I have those running in a 3x3, using the Controller 69 pro+, to automate. The cubic ft. of your grow space, will dictate which, and how many fans you need, and what size humidifier you'll need. In my case I prolly spent $600 - $700.
Beeswings
Well-Known Member
I'm running a similar set up but Vivosun with there controller and lights and fans and the whole setup I think I have $800 into. Kind of a large investment but pays for itself fast if you're used to buying smoke. And I know what I'm getting and what it was grown with.
UnknownRemedy
Well-Known Member
Best of luck! I'm still learning as well, and I think I always will be so don't get discouraged by the information out there. Just keep tweaking things here and there until you get it just right.
Budzbuddha
Well-Known Member
Absolutely pee on it
ScroteCombover
Member
I've seen, over multiple grows/cultivars, that terps peak, change, then start to diminish in late flower. I've seen plants that smelled like pure loud strawberry, change to over ripe melon, then to vaguely sweet light on terps. I often pull 'early' for peak terps. Might be time.
amneziaHaze
Well-Known Member
hydro and soil are same difficulty just soil you visit less often and you guess whats inside it while water you visit almost every day and instruments tell you whats in it.if you want to do hydro i would recommend starting with it.soil will not help you learn anything for hydro.