What Is GrowVPD Pro?

GrowVPD Pro is a free, offline-first app for Android and iPhone that gives you everything you need to manage indoor grows. It combines a VPD chart, a full grow diary, PPFD light guide, nutrient calculators, plant disease identification, equipment profiles, and smart device automation — all in a single app. No account required, no internet needed for core features.

Whether you are a first-time grower or a seasoned cultivator with a multi-tent setup, the app scales from simple daily logging to automated climate control with Tuya / Smart Life and Mars Hydro devices (AC Infinity and other brands are implemented and being verified with growers who own them).

Download and First Launch

GrowVPD Pro is coming soon to Google Play and the App Store — see how to get the app. On first launch you will see a short onboarding walkthrough that introduces the main features. You can skip it if you prefer, but it is worth the 30 seconds.

The app works entirely offline. You only need an internet connection if you want to connect smart devices or share data.

The 9 Tabs Explained

The tab bar at the top of the screen gives you quick access to every section of the app. Here is what each tab does:

  1. VPD — Interactive VPD heatmap chart. Enter temperature and humidity to see your VPD value, color-coded by growth stage. Supports Bluetooth sensor input and smart device integration.
  2. PPFD/DLI — Light meter (using your phone’s light sensor, a Pro feature) and a PPFD reference guide. Shows optimal light levels for each growth stage.
  3. Automation — Connect smart devices, create rooms and tents, set automation rules, and monitor your environment in real time. The free version covers one tent, three devices and one rule; Pro removes the limits.
  4. Diary — Your grow journal. Log entries — weekly, daily or by the hour — with temperature, humidity, VPD, pH, EC, nutrients, photos, and notes. Track multiple grows simultaneously (the free version keeps one active grow).
  5. Templates — Pre-built and custom grow templates. Start a new grow from a template to save time.
  6. Calculator — Nutrient calculator for your bottles, adjusted per growth stage, plus soil mix, living soil, yield and fan size (CFM) calculators.
  7. Plant Guide — Visual guide to plant health, deficiencies, diseases, and training techniques.
  8. Equipment — A database of lights, tents, fans and other gear, with an equipment advisor and a setup builder.
  9. Settings — Smart devices and sync, theme, language (11 available), units, PIN lock, biometric security, and backup and export options.

Setting Up Your First Grow

Head to the Diary tab and tap the "+" button to create a new grow. Setup takes four short steps:

  1. Plant — Give your grow a name you will recognize, like "Tent A - Spring 2026", enter the variety you are growing, say where it grows (indoor, outdoor or greenhouse), and optionally pick a grow template and how many weeks each stage will run.
  2. Space — Select your growing medium (soil, coco, hydro, etc.), how you water, and the pot size.
  3. Feeding — Pick a manufacturer’s feeding plan, or tick the bottles you have at home.
  4. Gear — Choose your light (LED, HPS, CMH, etc.), tent, fans, filter and humidity control.

The grow starts on the day you create it. Once created, your grow appears in the diary list. Tap it to start adding entries.

Tip: Use the Templates tab to start from a pre-built grow plan. Templates include stage durations, week-by-week targets for VPD, temperature, humidity and light, and tips for every week.

Adding Your First Entry

Inside your grow, tap the "+" button to add an entry; for quick readings on a particular day or hour, use Add data in that week’s section. The entry form includes:

  • Temperature and Humidity — Enter your readings. The app calculates VPD automatically.
  • Growth Stage — Select the stage, from germination to harvest. Your readings are compared with the targets for that stage.
  • pH and EC — Track your water or nutrient solution quality.
  • PPFD — Log your light intensity reading.
  • Nutrients — Record what you fed and how much.
  • Photos — Attach photos directly from your camera or gallery. Take regular photos to build a visual timeline.
  • Notes — Freeform text for anything else: observations, changes, reminders.

After saving, you will see the entry in your grow timeline with the VPD value highlighted in green when it is inside the target range for that stage, blue when it is too low and red when it is too high.

VPD Chart Basics

Switch to the VPD tab to see the interactive heatmap. The chart shows VPD values across a range of temperatures and humidity levels:

  • Green cells = 0.4–1.2 kPa, the range for young plants and vegetative growth.
  • Blue cells = VPD too low (under-transpiration, risk of mold).
  • Orange cells = 1.2–1.6 kPa, the flowering range.
  • Red cells = VPD too high (over-transpiration, plant stress).

Tap any cell to see its exact temperature, humidity, and VPD value. The outlined band on top of the colors is the target for your plant’s stage; it follows the grow in the tent you select at the top of the chart.

If you have a Bluetooth temperature/humidity sensor, the chart can read live data and show your current position directly on the heatmap.

Connect Smart Devices (Optional)

If you use Tuya / Smart Life or Mars Hydro devices (AC Infinity, Spider Farmer and other brands are implemented and being verified with growers who own them), head to the Automation tab or Settings > Smart devices to link your devices. Once connected, you can:

  • See live sensor readings on the VPD chart
  • Automate fans, humidifiers, and lights based on VPD rules
  • Auto-capture timelapse photos from Tuya cameras

Automation works in the free version for one tent, three devices and one rule; Pro removes those limits. Check out our Tuya connection guide or Mars Hydro connection guide for step-by-step instructions.

Tips for Beginners

Start with a template. Templates give you a proven schedule to follow. You can always customize later.
Check VPD daily. Consistent VPD is more important than hitting a perfect number once. Aim for stability within the green zone.
Take photos every day. It feels unnecessary at first, but a visual history is invaluable for comparing grows, diagnosing problems, and tracking progress.
Log nutrients and pH. When something goes wrong, having historical data makes troubleshooting much faster.

That is everything you need to get going. The best way to learn the app is to use it — create a grow, log a few entries, and explore the tabs. The interface is designed to be self-explanatory, and every feature is accessible from the main navigation.