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The Ultimate Vapor Pressure Deficit (VPD) Guide

"Why devote an entire guide to VPD?" you might ask. The answer is that the vapor pressure deficit (VPD) is extremely important for growing plants.

VPD helps you identify the correct range of temperature and humidity to aim for in your grow space. With VPD you can achieve the best results while avoiding pest and environmental problems. VPD also controls plant transpiration rates, stomata opening, CO2 uptake, nutrient uptake, and plant stress.

If you master VPD, you master your environment, and become a better grower.

VPD Chart Maker and Calculator

VPD Chart Maker and Calculator

VPD and Indoor Growing

Indoor growing comes with huge advantages. You get to have control over the environment that your plants grow in. Environment is one of the essential “knobs” you can twist in order to get better results in your grow, and VPD is the key part of that formula.

Take the Guesswork Out Of VPD

VPD Chart Maker and Calculator

Learn how to dial in your grow room's environment using VPD.

    Sign up to receive our customizable VPD chart maker and calculator, product info, giveaways, and discounts.

    Peter Koverda

    Peter Koverda

    Co-founder and CTO at Pulse

    12 Responses

    Bill Myers

    Bill Myers

    September 09, 2021

    Looks like a decent chart but I have to log into my Google account to be able to use it? That’s a deal breaker for me so thanks but no thanks.

    Anything that needs Google or F**kBook to run is a non-starter in my books. I avoid that and other spyware as much as humanly possible.

    Demeter

    Demeter

    September 09, 2021

    Why do you use 238.3 in this formula when Tetens uses 237.3? https://en.wikipedia.org/wiki/Tetens_equation

    SVP = 610.78 x e^(T / (T +238.3) x 17.2694))

    Alex

    Alex

    September 09, 2021

    Hello, I tried to convert the formula into a tiny C code, but when I execute it the resulting number is far off from the result of your VPD calculator.. Thanks for your help! The code(Online compiler): https://onlinegdb.com/4DwArRBpy

    Fadderall

    Fadderall

    September 09, 2021

    Something seems amiss. The first page of the spreadsheet gives Air and Plant VPD. Which number are we supposed to use with the chart maker? Also, I have tried various number configurations including picking numbers on the chart that should be 1.0 VPD and the calculator always shows over 2.2 plant VPD and ~.2 Air VPD. Neither number looks correct.

    Can you help me figure out what I am doing wrong? Is it Plant or Air VPD that we are concentrating on?
    Thanks

    Andrew

    Andrew

    September 09, 2021

    Will my grow room running co2 and being at a higher temp because of this change my range ? My room is dialed in to 84 degrees and 45.8 giving me a 2.2 vpd . Does running co2 change the vpd range similar to how it raises the temp recommendations ?

    Jim

    Jim

    June 10, 2021

    When running co2 do you increase vpd?

    Peter Koverda

    Peter Koverda

    June 30, 2020

    Hi Justin, here’s a link to the dew point guide: https://hello.pulsegrow.com/dew-point

    gazoo

    gazoo

    June 30, 2020

    Is there a Color breakdown for the zones
    Example for VEG There is the Green zone with a brighter yellow zone before and after.
    Curious Is the first yellow zone for maybe EARLY VEG and the second Yellow after the green zone
    for Late Veg. I ask because I have other charts that are set up that way ?

    Thanks in advance

    Robert Hayden

    Robert Hayden

    June 30, 2020

    How do you measure VPD without taking IR readings of your leaf temp?

    Thomas davis

    Thomas davis

    June 30, 2020

    Like to buy the chart an in the near future get the device . thankyou

    Carlo

    Carlo

    March 16, 2020

    I find it strange that in the VPD chart on the x axis 0 is on the right and on the y axis lower numbers are on top.
    Both axes should be the other way around.
    But the story as a whole is very interesting.
    Thank you.

    Justin

    Justin

    March 13, 2020

    Can’t find dew point page can you send me a link

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