We created VPD Charts with the mission to simplify vapor pressure deficit (VPD), making it easily understandable and useful for growers of all experience levels. Our goal is to ensure that VPD information is readily available and actionable, empowering everyone, from beginners to seasoned professionals, to optimize their growing conditions effectively.
Every grower hits a point where humidity and temperature readings alone stop being enough. You're adjusting, tweaking, troubleshooting — but without a number that combines both variables into something meaningful, you're always guessing.
VPD is that number. It exists in professional horticulture textbooks and commercial greenhouse software. But for most independent growers it was buried behind jargon, paywalls, or tools that required a spreadsheet to operate.
We built VPD Charts to fix that. No account. No paywall. No unnecessary complexity. Just the number you need and the context to understand it.
Growers deserve access to the same environmental data that commercial facilities use — without needing a software budget to get it.
VPD is not just a climate metric — it is a window into what your plant is actually experiencing. The same humidity reading at two different temperatures produces completely different results at the leaf surface. Understanding that difference is what separates reactive growing from intentional growing.
Our approach is to take the science seriously without making it inaccessible. Every calculation in our tool uses the Tetens formula — the same standard used in professional controlled environment agriculture.
We are not trying to simplify VPD into something it is not. We are trying to present it clearly so growers at every level can use it confidently.
Enter air temperature, leaf temperature, and relative humidity — get your VPD value instantly with a visual zone indicator and crop-specific guidance.
A pixel-rendered heatmap showing every temperature and humidity combination mapped to its VPD zone. Click anywhere on the chart to set your readings in real time.
Dedicated guides for cannabis, tomatoes, leafy greens, and more — with ideal VPD ranges by growth stage and practical, actionable targets.
Every piece of content is written to be understood the first time. No unnecessary jargon. No assumed knowledge. Just clear information that helps you decide.
VPD Charts was built for one type of person — someone who takes their growing seriously and wants accurate data to back their decisions. The scale does not matter.
Who want to stop guessing and start making precise environment decisions based on real numbers.
Managing changing conditions across seasons, daylight cycles, and variable weather patterns.
Who have already optimised their root zone and need the aerial environment to match the standard of their feeding programme.
Who need fast, reliable VPD data without expensive software subscriptions or lengthy onboarding.
Who wants to understand their environment at a deeper level — regardless of scale, crop, or experience level.
We built this tool around three principles that we think the existing options were missing.
We use established scientific formulas, not approximations. Leaf temperature is included in every calculation because ignoring it produces inaccurate results. We are not interested in tools that give comfortable answers — we want tools that give correct ones.
A tool you use every grow is worth more than a tool with every feature you never touch. We keep the interface fast and focused. Everything you need is visible immediately. Nothing is buried behind menus or settings.
Every guide and recommendation on this site is based on how VPD actually works — not on what is easiest to explain. We would rather give you a complete answer than a simplified one that misleads.
VPD Charts is an ongoing project — not a finished product.
Interactive real-time calculator with pixel heatmap, target mode, and crop selector.
Stage-by-stage VPD targets with practical temperature and humidity recommendations.
Peppers, cucumbers, herbs, and strawberries — with the same stage-by-stage depth.
A diagnostic tool that reads your inputs and suggests specific adjustments by stage and symptom.
A downloadable wall chart you can pin to your grow room and reference without a screen.
Some pages on this site include recommendations for measuring equipment, environmental controllers, and grow room tools. These recommendations exist because accurate VPD management requires accurate inputs — and we want to point you toward tools that actually work.
We are straightforward about this: some recommendations may include affiliate links. When they do, the cost to you does not change. Our editorial position does not change either. We only recommend tools we would use ourselves or that are genuinely well-regarded in the growing community.
You now know what we built and why. The best way to see if it works for you is to use it — enter your current temperature and humidity and see your VPD zone instantly.