Can someone look at these values (temp, rh, vpd) and tell me if they look good?

[chuey316]

I am building an automated system and I'm working on a few code tweaks. I think I may have it now, but I'd like for people far more knowledgeable at cultivation than myself to see if the values that my system calculated for these 4 Afghan Kush in a 3x4 tent with 3x3 being used to grow under a 400w MH for veg, and 400w HPS for flower look good, or If i need to make some edits to the dynamic scaling code.

VPD is prioritized during veg, with RH caps in place, and RH is prioritized in flower. The system will operate a heater, humidifier, and dehumidifier to keep the values in range, and each value will drift between the two numbers, meaning that if the temp hits the lower value, the heater will come on and shut off at the higher value. Then the temp would slowly drift back to the lower value and the process would repeat. Same for RH/VPD.

Vegetative Stage (4 weeks)​

Veg Week 1:
Day Temp: 77–81°F
Day Humidity: 70–75%
Night Temp: 70–74°F
Night Humidity: 65–70%
VPD: 0.81–1.14 kPa

Veg Week 2:
Day Temp: 75–79°F
Day Humidity: 65–70%
Night Temp: 68–72°F
Night Humidity: 60–65%
VPD: 0.94–1.28 kPa

Veg Week 3:
Day Temp: 74–78°F
Day Humidity: 60–65%
Night Temp: 68–70°F
Night Humidity: 55–60%
VPD: 1.04–1.41 kPa

Veg Week 4:
Day Temp: 73–77°F
Day Humidity: 58–62%
Night Temp: 68–70°F
Night Humidity: 55–60%
VPD: 1.08–1.38 kPa

---

Flower Stage (10 weeks)​

Flower Week 1:
Day Temp: 74–78°F
Day Humidity: 57–62%
Night Temp: 64–68°F
Night Humidity: 55–60%
VPD: 1.08–1.45 kPa

Flower Week 2:
Day Temp: 74–77°F
Day Humidity: 55–60%
Night Temp: 64–67°F
Night Humidity: 53–58%
VPD: 1.15–1.57 kPa

Flower Week 3:
Day Temp: 73–76°F
Day Humidity: 53–58%
Night Temp: 63–66°F
Night Humidity: 51–56%
VPD: 1.20–1.62 kPa

Flower Week 4:
Day Temp: 72–76°F
Day Humidity: 50–55%
Night Temp: 63–66°F
Night Humidity: 49–54%
VPD: 1.28–1.72 kPa

Flower Week 5:
Day Temp: 72–75°F
Day Humidity: 48–53%
Night Temp: 62–65°F
Night Humidity: 47–52%
VPD: 1.32–1.80 kPa

Flower Week 6:
Day Temp: 71–74°F
Day Humidity: 46–51%
Night Temp: 62–65°F
Night Humidity: 45–50%
VPD: 1.40–1.89 kPa

Flower Week 7:
Day Temp: 70–74°F
Day Humidity: 44–49%
Night Temp: 61–64°F
Night Humidity: 43–48%
VPD: 1.43–1.95 kPa

Flower Week 8:
Day Temp: 70–73°F
Day Humidity: 41–46%
Night Temp: 61–64°F
Night Humidity: 41–46%
VPD: 1.40–1.95 kPa

Flower Week 9:
Day Temp: 69–72°F
Day Humidity: 39–44%
Night Temp: 61–64°F
Night Humidity: 39–44%
VPD: 1.38–1.95 kPa

Flower Week 10:
Day Temp: 68–72°F
Day Humidity: 37–42%
Night Temp: 61–63°F
Night Humidity: 37–42%
VPD: 1.35–1.95 kPa

 

[trygrowup]

I think they mixed up the temps - last week of veg - start week of bloom

 

[chuey316]

I think they mixed up the temps - last week of veg - start week of bloom

Good catch. I tried to modify the code but the best I can get it is to output the same temp for week one of flower as week 4 of veg without throwing off the numbers later in flower. Going to keep tweaking a bit though.

 

[trygrowup]

My 10 cents is i don't think you gonna use it that much. It looks like it's meant for a specific strain.

I would think there is a big difference form indica to sativa and the mix is also never the same.

But as guidelines maybe? I know very little about humidity, temp and VDP

 

[MrSativa]

late flowering vpd swing from1.35 to 195 is way to big

 

[Vick_Vinegar]

Man you guys get way too caught up in obsessing with numbers and overthinking shit.

Makes me so glad Ive never had to sit around plotting numbers and graphs for everything and just grew plants instead lol.

 

[WinJr63]

Check this out, very nice I use it .

Im running around 77f 67rh to stay around 1.10 vpd

 

[Brother_Antioch]

Man you guys get way too caught up in obsessing with numbers and overthinking shit.

Makes me so glad Ive never had to sit around plotting numbers and graphs for everything and just grew plants instead lol.

"obsessing with numbers" is what can turn a good grow into a great grow. It's not for everyone, true.

 

[chuey316]

My 10 cents is i don't think you gonna use it that much. It looks like it's meant for a specific strain.

I would think there is a big difference form indica to sativa and the mix is also never the same.

But as guidelines maybe? I know very little about humidity, temp and VDP

It can be used for any strain. You just input the starting and ending temp/rh/vpd numbers for veg and flower and it automatically calculates each week on a sliding scale, while attempting to keep the values in the optimal ranges. You can manually adjust as well if you wanna run a bit warmer, or drop the temp in late flower etc. I mainly made it to get the conditions as near to ideal as possible, without constantly having to go and make manual adjustments. Each week can be tweaked or just set manually depending how a strain or pheno reacts as well.

It should pretty much do everything that the 5 digit commercial systems can do and then some. At least once I get a few bit of code ironed out.

 

[chuey316]

Check this out, very nice I use it .

Im running around 77f 67rh to stay around 1.10 vpd

Thanks. The values from this chart are included in the code.

 

[chuey316]

Man you guys get way too caught up in obsessing with numbers and overthinking shit.

Makes me so glad Ive never had to sit around plotting numbers and graphs for everything and just grew plants instead lol.

I'll admit I am a perfectionist and I definitely obsess a bit, but this isn't about a grow really. It's about getting my software right, but to do that I need to rely on people who know far more than me when it comes to proper conditions, who they should change week to week, etc.

 

[trygrowup]

Ahh there you see. I don't know much about it as i said. Also i didn't realize you could adjust it like that.

Sounds better now

Thanks for clarifying

 

[chuey316]

I forgot that I coded in VPD stage‑based control. I ran the calculation again and this is what I got. Still starting off flower a bit warmer than it ends veg, but I haven't touched the veg code yet. Focusing on one at a time. Anything still jump out as out of the proper/optimal ranges for flower?

Flower Week 1:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 2:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 3:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 4:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 5:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 6:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 7:
Day Temp: 68–72°F
Day Humidity: 40–45%
Night Temp: 61–63°F
Night Humidity: 40–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.0–1.2 kPa

Flower Week 8:
Day Temp: 68–72°F
Day Humidity: 40–45%
Night Temp: 61–63°F
Night Humidity: 40–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.0–1.2 kPa

Flower Week 9:
Day Temp: 68–72°F
Day Humidity: 38–43%
Night Temp: 61–63°F
Night Humidity: 38–43%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Flower Week 10:
Day Temp: 68–72°F
Day Humidity: 38–43%
Night Temp: 61–63°F
Night Humidity: 38–43%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

 

[chuey316]

If the values in my post above are still not good, can someone please copy the post and edit them so I know what conditions to get this thing to return? Would appreciate it. Thanks.

 

[Grownsince95]

I forgot that I coded in VPD stage‑based control. I ran the calculation again and this is what I got. Anything still jump out as out of the proper/optimal ranges?

Flower Week 1:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 2:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 3:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 4:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 5:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 6:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 7:
Day Temp: 68–72°F
Day Humidity: 40–45%
Night Temp: 61–63°F
Night Humidity: 40–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.0–1.2 kPa

Flower Week 8:
Day Temp: 68–72°F
Day Humidity: 40–45%
Night Temp: 61–63°F
Night Humidity: 40–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.0–1.2 kPa

Flower Week 9:
Day Temp: 68–72°F
Day Humidity: 38–43%
Night Temp: 61–63°F
Night Humidity: 38–43%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Flower Week 10:
Day Temp: 68–72°F
Day Humidity: 38–43%
Night Temp: 61–63°F
Night Humidity: 38–43%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

You don't measure VPD. You only need your controller to measure temp and rh then calculate VPD. Let's say for instance you set your target at 1.05, the system should look at the upper and lower limits you've set for temp (72°-78°) and rh (60-65%) and then decide what action to take.

You can have 1.05 vpd at 72° or 78° so what's different? The RH is 61% and 68%. 68 is outside our programmed acceptable range so 1.05 vpd at 78° is no bueno. The program would then trigger an exhaust fan or AC to reduce heat. It works both ways.

 

[WinJr63]

I am building an automated system and I'm working on a few code tweaks. I think I may have it now, but I'd like for people far more knowledgeable at cultivation than myself to see if the values that my system calculated for these 4 Afghan Kush in a 3x4 tent with 3x3 being used to grow under a 400w MH for veg, and 400w HPS for flower look good, or If i need to make some edits to the dynamic scaling code.

VPD is prioritized during veg, with RH caps in place, and RH is prioritized in flower. The system will operate a heater, humidifier, and dehumidifier to keep the values in range, and each value will drift between the two numbers, meaning that if the temp hits the lower value, the heater will come on and shut off at the higher value. Then the temp would slowly drift back to the lower value and the process would repeat. Same for RH/VPD.

Vegetative Stage (4 weeks)​

Veg Week 1:
Day Temp: 77–81°F
Day Humidity: 70–75%
Night Temp: 70–74°F
Night Humidity: 65–70%
VPD: 0.81–1.14 kPa

Veg Week 2:
Day Temp: 75–79°F
Day Humidity: 65–70%
Night Temp: 68–72°F
Night Humidity: 60–65%
VPD: 0.94–1.28 kPa

Veg Week 3:
Day Temp: 74–78°F
Day Humidity: 60–65%
Night Temp: 68–70°F
Night Humidity: 55–60%
VPD: 1.04–1.41 kPa

Veg Week 4:
Day Temp: 73–77°F
Day Humidity: 58–62%
Night Temp: 68–70°F
Night Humidity: 55–60%
VPD: 1.08–1.38 kPa

---

Flower Stage (10 weeks)​

Flower Week 1:
Day Temp: 74–78°F
Day Humidity: 57–62%
Night Temp: 64–68°F
Night Humidity: 55–60%
VPD: 1.08–1.45 kPa

Flower Week 2:
Day Temp: 74–77°F
Day Humidity: 55–60%
Night Temp: 64–67°F
Night Humidity: 53–58%
VPD: 1.15–1.57 kPa

Flower Week 3:
Day Temp: 73–76°F
Day Humidity: 53–58%
Night Temp: 63–66°F
Night Humidity: 51–56%
VPD: 1.20–1.62 kPa

Flower Week 4:
Day Temp: 72–76°F
Day Humidity: 50–55%
Night Temp: 63–66°F
Night Humidity: 49–54%
VPD: 1.28–1.72 kPa

Flower Week 5:
Day Temp: 72–75°F
Day Humidity: 48–53%
Night Temp: 62–65°F
Night Humidity: 47–52%
VPD: 1.32–1.80 kPa

Flower Week 6:
Day Temp: 71–74°F
Day Humidity: 46–51%
Night Temp: 62–65°F
Night Humidity: 45–50%
VPD: 1.40–1.89 kPa

Flower Week 7:
Day Temp: 70–74°F
Day Humidity: 44–49%
Night Temp: 61–64°F
Night Humidity: 43–48%
VPD: 1.43–1.95 kPa

Flower Week 8:
Day Temp: 70–73°F
Day Humidity: 41–46%
Night Temp: 61–64°F
Night Humidity: 41–46%
VPD: 1.40–1.95 kPa

Flower Week 9:
Day Temp: 69–72°F
Day Humidity: 39–44%
Night Temp: 61–64°F
Night Humidity: 39–44%
VPD: 1.38–1.95 kPa

Flower Week 10:
Day Temp: 68–72°F
Day Humidity: 37–42%
Night Temp: 61–63°F
Night Humidity: 37–42%
VPD:

I forgot that I coded in VPD stage‑based control. I ran the calculation again and this is what I got. Still starting off flower a bit warmer than it ends veg, but I haven't touched the veg code yet. Focusing on one at a time. Anything still jump out as out of the proper/optimal ranges for flower?

Flower Week 1:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 2:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 3:
Day Temp: 75–80°F
Day Humidity: 55–60%
Night Temp: 65–70°F
Night Humidity: 50–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 4:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 5:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 6:
Day Temp: 72–76°F
Day Humidity: 48–53%
Night Temp: 63–67°F
Night Humidity: 45–50%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 7:
Day Temp: 68–72°F
Day Humidity: 40–45%
Night Temp: 61–63°F
Night Humidity: 40–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.0–1.2 kPa

Flower Week 8:
Day Temp: 68–72°F
Day Humidity: 40–45%
Night Temp: 61–63°F
Night Humidity: 40–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.0–1.2 kPa

Flower Week 9:
Day Temp: 68–72°F
Day Humidity: 38–43%
Night Temp: 61–63°F
Night Humidity: 38–43%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Flower Week 10:
Day Temp: 68–72°F
Day Humidity: 38–43%
Night Temp: 61–63°F
Night Humidity: 38–43%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Looks better.
I stayed below around 77f, once I saw the first pistil droped to 75f first time real grow didn't want to fry, lol

Happy Growing

 

[chuey316]

You don't measure VPD. You only need your controller to measure temp and rh then calculate VPD. Let's say for instance you set your target at 1.05, the system should look at the upper and lower limits you've set for temp (72°-78°) and rh (60-65%) and then decide what action to take.

You can have 1.05 vpd at 72° or 78° so what's different? The RH is 61% and 68%. 68 is outside our programmed acceptable range so 1.05 vpd at 78° is no bueno. The program would then trigger an exhaust fan or AC to reduce heat. It works both ways.

So vpd doesn't really matter so much as long as the temp and RH are in check, or am I misunderstanding? So would my values in the comment you quoted be acceptable?

I ran a few lines based on what I think you were saying, and had the system run a set range of temp and rh, and adjust as needed within those ranges, but never outside of them to achieve the most optimal vpd on the fly. This is what it came up with.

Flower Week 1:
Day Temp: 70–80°F
Day Humidity: 50–60%
Night Temp: 65–70°F
Night Humidity: 45–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 2:
Day Temp: 69–79°F
Day Humidity: 48–58%
Night Temp: 64–69°F
Night Humidity: 44–54%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 3:
Day Temp: 69–78°F
Day Humidity: 46–56%
Night Temp: 64–69°F
Night Humidity: 43–53%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 4:
Day Temp: 68–78°F
Day Humidity: 43–53%
Night Temp: 63–68°F
Night Humidity: 42–52%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 5:
Day Temp: 68–77°F
Day Humidity: 41–51%
Night Temp: 63–68°F
Night Humidity: 41–51%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 6:
Day Temp: 67–76°F
Day Humidity: 39–49%
Night Temp: 62–67°F
Night Humidity: 39–49%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 7:
Day Temp: 67–75°F
Day Humidity: 37–47%
Night Temp: 62–67°F
Night Humidity: 38–48%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Flower Week 8:
Day Temp: 66–75°F
Day Humidity: 34–44%
Night Temp: 61–66°F
Night Humidity: 37–47%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Flower Week 9:
Day Temp: 65–74°F
Day Humidity: 32–42%
Night Temp: 61–66°F
Night Humidity: 36–46%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.2–1.4 kPa

Flower Week 10:
Day Temp: 65–73°F
Day Humidity: 30–40%
Night Temp: 60–65°F
Night Humidity: 35–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.2–1.4 kPa

 

[chuey316]

Looks better.
I stayed below around 77f, once I saw the first pistil droped to 75f first time real grow didn't want to fry, lol

Happy Growing

Unfortunately I've got 4-5 months before I can start my next run. I have no AC in the basement and temps will be a bit too warm in late flower and drying if I start anytime soon so i'm just focusing all of my attention on building this automation system until I can start setting up in June/July. I love spending time with the ladies, but the main lady doesn't like it taking me away so much, so I'm going to use this to limit my time down there to trimming and watering. At least until I buy the pumps to set up auto watering as well since I have pot moisture monitoring coded in as well.

 

[WinJr63]

So vpd doesn't really matter so much as long as the temp and RH are in check, or am I misunderstanding? So would my values in the comment you quoted be acceptable?

I ran a few lines based on what I think you were saying, and had the system run a set range of temp and rh, and adjust as needed within those ranges, but never outside of them to achieve the most optimal vpd on the fly. This is what it came up with.

Flower Week 1:
Day Temp: 70–80°F
Day Humidity: 50–60%
Night Temp: 65–70°F
Night Humidity: 45–55%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 2:
Day Temp: 69–79°F
Day Humidity: 48–58%
Night Temp: 64–69°F
Night Humidity: 44–54%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 3:
Day Temp: 69–78°F
Day Humidity: 46–56%
Night Temp: 64–69°F
Night Humidity: 43–53%
Day VPD: 1.0–1.2 kPa
Night VPD: 0.8–1.0 kPa

Flower Week 4:
Day Temp: 68–78°F
Day Humidity: 43–53%
Night Temp: 63–68°F
Night Humidity: 42–52%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 5:
Day Temp: 68–77°F
Day Humidity: 41–51%
Night Temp: 63–68°F
Night Humidity: 41–51%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 6:
Day Temp: 67–76°F
Day Humidity: 39–49%
Night Temp: 62–67°F
Night Humidity: 39–49%
Day VPD: 1.2–1.4 kPa
Night VPD: 0.9–1.1 kPa

Flower Week 7:
Day Temp: 67–75°F
Day Humidity: 37–47%
Night Temp: 62–67°F
Night Humidity: 38–48%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Flower Week 8:
Day Temp: 66–75°F
Day Humidity: 34–44%
Night Temp: 61–66°F
Night Humidity: 37–47%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.1–1.3 kPa

Flower Week 9:
Day Temp: 65–74°F
Day Humidity: 32–42%
Night Temp: 61–66°F
Night Humidity: 36–46%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.2–1.4 kPa

Flower Week 10:
Day Temp: 65–73°F
Day Humidity: 30–40%
Night Temp: 60–65°F
Night Humidity: 35–45%
Day VPD: 1.3–1.5 kPa
Night VPD: 1.2–1.4 kPa

I would say yes VPD is important just as the DEW point is . Dew point should always be below your RH%.

 

[Phyto]

Don't live and die by VPD, it's a range. In the outdoors you can;t control it and the plants do just fine. Last summer I grew at 4000 ft elevation, in June-September the daytime temps ran from 70-95 degrees with 10-20% r/h. At night the temps were anywhere from 40 to 60 degrees with 70% r/h. Once Mid-September hit the daytime temps rarely got above 65 degrees with 20% humidity, at night 30 degrees with 70& r/h. I harvested in mid Oct, the two weeks before harvest the nightime temps were anywhere from 24 to 34 degreesm daytime in 50's. The morning I pulled them it was 18 degrees. The plants did fine, good harvest, good smoke.