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Average VPD

Cougar672

Cougar672

New member
Hello wise ones.
Most of the time i struggle to maintain an appropriate VPD hour to hour. Typically it is higher than desired with the light on, and lower than the target when lights are out. However, the average VPD for each day is usually pretty close to the sweet spot. The VPD never gets to an extreme high or low. I'm sure my plants would be better with a perfect VPD 24/7, but can anyone comment on how badly the VPD swings could effect the plant development?
 
wide range or varying VPD causes bud abortion and nutrient deficiencies during the fruiting/flowering phase. VPD changes as the cultivar matures and will speed up and increase yield if maintained at proper levels. fairly easy to control yet can be expensive also. Victory loves preparation
 
Hi, Cougar.
I'll nominate you for being one of the "wise ones". That you regularly hit your VPD targets illustrates your grow skill. I would guess many forum participants do not even know what VPD is.
Given that, why? Extra yield? (How much?) Better bud? (In what way?)
My real point is cannabis is a weed and grows like one. I grow in a 20' x 10' x 6.5' polytunnel green house and VPD varies quite a bit. Same with my 8' in ground monsters getting close to harvest. I always get plenty (yield = more than I can use) of good to great bud (better = lots of THC and can smoke another bowl if wanted). Good genetics helps.
I originally agonized over all kinds of things - pH, nute burn, etc - until I finally realized that when I get the basics correct, the plants are fully capable of taking care of themselves AND me. 😎
 
My VPD varies maybe +/- 10% either side of ideal just with dehumidification in a 10 to 20 minute window with full climate control...temps vary very little, maybe +/- 0.5⁰C but humidity changes quickly, all before late flower stage. At late flower stage dehumidification runs non stop which takes out all variance and the VPD remains pretty solid and doesnt vary much at all with humidity low 40s to high 30s at harvest time.

It doesn't adversely effect yields or quality as long as I can maintain the average Im chasing. It may even be a little beneficial to have some variance.

Good airflow throughout the canopy especially for air changeover in the buds is extremely important as temps inside buds will go too high without good airflow which will negatively impact density, yield and potency.
 
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Thanks everyone for the responses.
Allotrope1000 I'm not actually one of the wise ones, just getting lucky on this current grow. Due to circumstances current grow is in my garage in Connecticut. Turns out to be better than my basement, where I struggled with heat in the summer and dryness in the winter.
Bluey Thanks for your insight. I don't have the sweet set up you do but I do what I can within my limits. I currently have 1 weak fan on my canopy and have been procrastinating on adding another because I've been lazy to clean it. I'll do that after the lights come on.
Happy growing and happy smoking.
 
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