First grow in 15+ years. Got some nice Strawberry OG Cookies autoflowers. Im a little over week in. I have the AC Infinity 2x4 grow tent/system.
First issue was the humidity so I got the cloudforge humidifier to increase. I was in the 40%-50% range. Needed to up it during the seedling and veg state. The range for seedlings should be between 70-80 Temp and 60-70% RH. We’ll, then I learned about VPD. My VPD in this stage should be about 0.6-0.8. To get there, I have to set my Temp at 83° and RH around 75%.
So, is it ok to be outside the Temp and RH range, if the VPD is where it needs to be?
This is all new to me. Last time I did this, LEDs were just coming out. Autos were trash. And VPD wasn’t in my vocabulary. Just invested I’m this system and wanted to see better results that 15 years ago.
Any help would be great. I don’t know if I should just go back to focusing on Temp and RH or keep aim at VPD. It sounds like VPD is the the difference between good and great. So that’s what I would like to do. But if I’m hurting my girls trying to get there, does it make sense? They look happy. I just would like to know of RH/Temp matter as much if your VPD is good… thanks in advance!
I don’t run auto’s but I think this question is more about VPD. General rule of thumb is you should throughly know your temp and RH at all times of day and night in your garden. After a run or two focusing on the temps and RH fluctuations day and night you will see on a VPD chart how difficult it is to keep these parameters in check for VPD constantly. The good news is if you keep proper recommended temps and RH day and night and avoiding the lights off RH spikes you will find your VPD is actually in tolerance of recommend range. Another thing to consider is that’s leaf surface temps for VPD not garden temps. You need to actually get an inexpensive infared heat gun from Home Depot or whatever. The leaf surface temp is the reading your after to properly monitor VPD.
Also those temps and RH levels that high 83 and 75 are going to require CO2 and would still be very concerning for all but the most skilled gardeners. I wouldn’t recommend such advanced techniques for best success work your way up to high temp high humidity. Things go south quickly with those numbers. We like to stay below 60 RH and lowest temp you can manage really. 75 to 80 degrees is hard enough to manage.
I really appreciate this response. I actually had a IR gun delivered last night. That changed everything! With the leaf offset now in place. I’m at a nice 77 temp and 64 RH. VPD at 0.7 for my seedlings going into veg. It’s perfect. I know I’m a beginner but I am a research nerd and I I’m going for it! I’ll keep this post update to show progress. Also, I used AC infinity set up so it’s easy to focus on VPD with my limited experience. I’m a perfectionist haha I want the best possible. I think I finally got it, the IR gun and leaf temp was a GAME CHANGER. thank you!!!
I know I’m a beginner and should keep it more simple. But I have a good understanding of alot of things. I’m doing the sunrise/sunset setting now. I know the views on this are mixed. But I’m all about organic and mother nature. Even if it doesn’t do anything I’m not losing alot time valuable light time. It’s 6 minutes for sunrise and 6 for sunset. 12 minutes total. I also have some UV lights. Again the views are mixed on this. I’m not using them expecting a change in finaly product. It’s more about the help keeping everything clean and sterilized. Not using them yet. Will use them when I get closer to flower. Just a few minutes in the morning and night. Nothing overkill. If I didn’t mention, I’m using purple cow soil. I used 1 gallon decomposing fabric with the veg mix. Put that in a 5 gallon with the flower mix. Right now I’m not adding additional nutes. Just purple cow supercharger (sugars and stuff) and liquidlife (bacteria fungi). I use a mix containing both for soil watering. Occasionally I use just the supercharger for foliage spray. Things look great! I’m stoked! This is so far beyond the primitive shit I had 15 years ago. I do have organic nutes to add in my water if it looks like the soil doesn’t have enough at any point. The idea was that the root will probably grow in the 1 gallon during seedling and veg and make their way into the flower soil as they approach flower. I’ve read soil nutrients can be used up in 45 days. So this give me 45 days with veg mix and 45 days with flower mix and by the end the girls should be ready to harvest
Wow… you are jumping in bolth feet cheers !!! Sounds a lot more inline with recommended environments. You are definitely diligent. That will help you along they way !!!
yes. actually if you can hit the high 70’s and low 80’s F in veg theyll grow faster. humidity for veg looks good.
yes.
yes in the sense that its ok. but hitting VPD while staying in a hot humid for veg is best.
both matter. tht target VPD will ensure good transpiration rate. so you have to hit that VPD preferably with the 80F and 75% Humidity - FOR VEG - (now for true VPD you have to measure leaf temperature btw, not just tent temperature)
all of this to tell you chill, dont worry, just make sure you have a hot humid room in veg (75-85F, 60-75RH) and youll be just fine. in veg growing faster is what youll get with ideal vpd and temp/rh range. so even if you dont hit it, youlld just see slower growth in general, not much else in terms of issues. again, talking veg.
For flower that will change your temps in flower will start highish (75-80F) and by the middle to end of flower your temps should be in the 70s range - ideally should not be higher than 77F but nearing 80-82+F isnt the worst. for flowering, your Humidity should be from 45-55, going higher you risk mold, while targetting a VPD of .8 to 1.2 nearing the end of flower. so you ensure good transpiration rate, and not going higher that 70’s F will ensure you keep those trichomes in good shape, and not going over 55RH will ensure you dont risk rot. (also very important, air circulation).
Can’t go outside unfortunately. I’ll yield less because of 12 minutes? 6 min sunrise and 6 min sunset? I just think mimicking nature would be ideal. But optimizing it obviously. All I meant was I use organic living soil with biolife mixed in my water adding good bacteria and fungi. I clarified alot of this in my other post further down the line. Maybe read that one and let me know! I did get and IR gun ans set the offset of vpd vs leaf surface temp and it made a huge difference. Can hit my vpd perfect and have my Temp and RH in the range for veg. Yes, I know flower it will change and I’m looking forward to it!
Thank you! While it’s my first time in along time. I love all the new tech and advances. When I get into something, I go all in. I read and research as much as possible before my grow. So I knew exactly what I was doing with my tent, lights, exhaust, humidifier, veg soil, flower soil, sugars, bacteria, fungi, RH, Temp, VPD, extra nutes if needed, cal mag, I’m ready. Was just struggling with VPD and the IR gun gave me my adjustment number and changed everything. I’m really happy. I want to see a good return on my investment. Obviously, there is more to learn as always. Just glad that IR gun fixed my biggest problem. Super happy now. They look happy.
Basic nature rules
If your temps are high, raise rh
If your temps are low, lower rh
Plants grow best at high heat and high rh, think amazon rain forest
Trichomes loves low rh (dryness) and high temps, but those two make a not good environment for growing, so for trichomes that’s different.
Mostly, it depends on the stage your at.
At 30c, 70-80 rh, you should see very fast growth.
That’s the solid parameters I aim for when I veg.
At flower I start strong staying for a week or two on 28-30c and 70-80 rh, after that when buds start to form I keep it on the lower end, at 28c ± with avg 40-60 rh.
Towards the end of flower you wanna go lower than 24c and be at 20-40 rh for best trichome results.
I’d use the IR gun to compare leaf temps to ambient (a sheet of white paper, held vertically at the level of the leaf works well. Just hold it up and aim your IR gun at it to get the ambient temp, then aim directly at the leaf to get the leaf temp.) You want your plant transpiring, which will drive the leaf temps down below ambient by a few degrees. If you don’t see a lower leaf temp, that basically means the rate of evaporation at the leaf is low, and the plant is unable to effectively move water. This means it’s not able to effectively move nutrients either, and that metabolism is slowed. My suggestion is to adjust one parameter at a time and see how it affects the difference between leaf surface temp and ambient.
Yeah I’m seeing about a 5 degree difference between leaf and ambient. Which I’ve read is common with LEDs. I adjusted my controller with a -5 degree offset and it’s at a nice 77° Temp, 58 RH, 0.8 VPD
