Cannabis cultivation · iOS & Android · Coming soon

A master grower in your pocket.

A mobile app for serious cultivators. AI-generated grow plans, photo-based diagnosis, environment analysis from your AC Infinity controller, and smart reminders that never miss a day. No accounts. No subscriptions. Your data stays on your device.

Get the app → How it works
Servers 0
Your data On device
Typical cost ~$2/mo
Subscriptions None
01 · What it is

A cultivation tool built by a grower, for growers who care about the craft.

Master Grower is what you reach for instead of a spiral notebook, a half-forgotten spreadsheet, and a Reddit tab open in the background. It tracks your grow, reminds you what to do, analyzes your environment data, and gives you a master cultivator to text when something looks off.

It's built for indoor, outdoor, and greenhouse growers running autos or photos, in coco or soil or living soil, with hand-watering or autopot or DWC. The AI knows your exact setup because you told it once.

  • → Guided grow wizard Answer a handful of questions, get a complete grow plan with daily targets, tasks, and supplies — researched and synthesized by Claude.
  • → Photo diagnosis in chat Snap a yellowing fan leaf, get a diagnosis back in seconds with the full context of your system, not generic advice.
  • → Environment analysis Import your AC Infinity CSV exports. The app scores each day against phase targets and flags drift that matters.
  • → Smart notifications Daily task batches, weekly digests, critical-task flags, in-shade snooze actions. Never miss a feed day.
02 · What's inside

Four features that do the real work.

The surface area is intentionally small. Every feature exists because it moves the grow forward.

Grow Wizard

Generate a complete grow plan in 90 seconds.

Six pages of questions about your cultivar, setup, medium, feed, and IPM. Claude researches each strain, synthesizes it all, and builds a grow file with phase targets, daily tasks, and a supply list. One tap to import.

Cultivation chat

A master grower who already knows your setup.

Global chat for general questions. Grow-specific chat with full context: strains, phase, targets, last seven days of environment data, recent journal entries. Send a photo, get a diagnosis. If action is warranted, it offers a one-tap task to add.

Environment analysis

Your AC Infinity data, actually read.

Import daily CSVs from your controller. The app scores each day against phase targets with a weighted 0–100. Dual analysis runs two AI passes — last 24 hours and the rolling seven days — so a recent problem isn't averaged away.

Smart notifications

Reliable reminders, no busywork.

Daily task batches by grow, weekly Sunday digest, critical-task flags, per-task time overrides, and shade-action snoozing (30 min / 1 hr / 3 hr / Tomorrow / Done) without opening the app. Notifications survive reboots.

The home screen

A quiet instrument panel for every grow.

Every active grow gets a card. Day count, days left, supplies to buy, tasks done. The instrument strip shows your current-phase targets — temp, RH, VPD, DLI — in the same uppercase mono the app uses everywhere, because numbers belong in monospace.

Tap the strip to see readings; tap a card for the full detail view with tasks, supplies, journal, and environment tabs.

03 · Privacy by architecture

Your grow lives on your device. The AI calls go straight to Anthropic with your key.

Cannabis is still federally illegal in the U.S. Growers have legitimate reasons to care where their data sleeps at night. Master Grower is built so the answer is simple — and so the parts that aren't simple are at least honest.

"There is no Master Grower server. There is no account. There is no middleman between you and the AI."

Grows, tasks, journal entries, photos, chat history — all of it lives only on your phone. The only network traffic the app ever makes is direct HTTPS to Anthropic, authenticated with your own API key, when you actively use an AI feature. Nothing else leaves the device.

Where your data actually goes.

The full picture, drawn honestly. Two boxes, one connection, no third box.

Your device
Lives here, stays here
  • Grow files & tasks
  • Journal entries
  • Photos
  • Chat history
  • Environment CSV imports
  • Your API key
Anthropic API
Only when you tap an AI feature
  • The prompt you sent
  • Curated grow context
  • Any photo you attached
  • Not used for training
  • 7-day log retention
  • No third parties
⬤ No Master Grower server

There's nothing in the middle.

No account, no sign-in, no telemetry, no analytics, no crash reporting, no ad SDKs. We can't see your data because there is no "we."

⬤ Your key, your budget

You hold the only key that unlocks AI.

Generate it in Anthropic's console, paste it in once, set your own spending cap. Revoke it and the app makes zero further API calls — instantly.

⬤ Anthropic's API terms

No training. 7-day logs.

API submissions are not used to train models, are retained for seven days, then deleted. Zero Data Retention is available for enterprise. Verified April 2026.

Want zero network traffic of any kind? Don't enter an API key. Task tracking, notifications, journal, environment charts, and grow file import/export all work fully offline. The AI features simply stay dormant until you decide otherwise.

04 · Get started

Three steps. About ten minutes, including a $5 Anthropic top-up.

01

Install the app.

Download Master Grower from the App Store or Google Play. The apps are currently being prepared for submission — check back soon, or follow the eyebrow above for status.

02

Get an Anthropic key.

Sign up at console.anthropic.com, add $5 of credit, generate an API key named master-grower.

03

Paste, verify, grow.

In Settings → Claude API, paste the key and tap Verify. A minimal test call confirms it works. Then open the wizard and build your first grow.

Download on the App Store Soon Get it on Google Play Soon
05 · What it costs

The app is free. You pay Anthropic directly, about the price of a coffee per month.

There's no subscription, no pro tier, no paywalled features. You pay Anthropic for the AI tokens you actually use — nothing more.

The app itself Free download from App Store / Google Play
Freeno in-app purchases
Grow plan generation One wizard run, one full grow
~$0.35per grow, once
Cultivation chat Roughly 20 messages per week
~$1.60per month
Environment analysis Weekly CSV import + AI review
~$0.04per month
Typical monthly total For an active grower running 2 grows
~$2–5direct to Anthropic

Set a spending cap in the Anthropic console. The app's Settings → API usage tab breaks down your spending by feature so you always know exactly where your tokens go.

06 · Questions worth answering

The things everyone asks first.

Why bring my own Anthropic API key?

Two reasons. First, it keeps the architecture honest, there's no Master Grower server in the middle adding latency, markup, or another database to be breached. Your prompts and photos go straight from your phone to Anthropic.

Second, it puts you in control of cost and access. You set the spending cap. If you ever want the app to stop calling Anthropic, you revoke the key and that's the end of it, no subscription to cancel.

What does Anthropic actually see when I use the AI?

Whatever you send in that specific call, your prompt, the curated context the app attaches (current grow, phase, targets, recent journal), and any photo you've explicitly attached. That's it. No location, no device ID, no analytics payload.

Per Anthropic's commercial API terms, that data isn't used to train their models, is retained for seven days, then deleted. Zero Data Retention is available under enterprise agreements.

What if I never enter an API key?

The app still works. Task tracking, notifications, journal, environment charts, AC Infinity CSV imports, grow file import/export — all of it runs fully offline with zero network traffic. The AI features simply stay dormant until you give them a key.

Why does it cost so little per month?

Because the app is careful with tokens. Chat context is curated — strain, phase, targets, recent observations — not a full dump of your state. Cheaper Claude models handle routine work. Opus is reserved for the one task where quality matters most: generating your full grow plan.

Settings → API usage shows you a per-feature breakdown so you can always see where your tokens are going.

When will the apps actually be available?

The Android version is feature-complete and the iOS build is being prepared on the same codebase. Both are headed for App Store and Google Play submission. The status indicator at the top of this page is the source of truth.

Is the source code open?

No. The app is closed-source for now. Privacy doesn't depend on open source — it depends on architecture. Master Grower has no backend, no telemetry, and no account system, which means there is structurally no place for your data to leak from on the app's side.

From the developer

I built Master Grower because I got tired of running a grow on three apps, two notebooks, and a tab full of half-remembered Reddit threads. The app I wanted didn't exist, so I made it. It's the tool I use on my own grows, every day. If something's broken or missing, that's because I haven't run into it yet and I'd like to hear about it.

— A grower, an indie developer