Do your plants keep dying? You're not alone, and it's probably not your fault.
Most plants fail because of one problem: light. Too little and they slowly starve. Too much and they burn out. Blackthumb gives you a Light Score for every plant and location in your home so you finally know what's going on.
— LIGHT SCORE CALCULATOR
Stop guessing. Enter your light readings (in lux, fc, or PPFD) and Blackthumb calculates your plant's Daily Light Integral (DLI) — the actual amount of usable light it receives each day. See instantly whether your Monstera is getting enough light in that corner, or if your grow light is doing its job. Compare against your plant's ideal range and get a clear "too low / in range / too high" rating.
Track natural light and grow light separately. See a confidence score that improves as you log more readings. Powered by real plant science, not vague color zones.
— CARE REMINDERS THAT ACTUALLY WORK
Set reminders for watering, fertilizing, rotating, misting, pruning, repotting, pest treatment, and health checks — for any plant or location. Snooze what you need to, perform what's due, and never wonder "did I water that one?" again.
Sub-reminders make your care routine smarter: set a fertilizing reminder that automatically triggers every 3rd time you water. No manual tracking needed.
— ORGANIZE BY SPACE, NOT JUST SPECIES
Your plants live in specific places — a bright windowsill, a dim shelf, a grow tent. Blackthumb organizes around locations (Living Room, Bedroom, Balcony) so you can see everything in a space at once and manage care by room.
Create collections to group plants however makes sense to you: new cuttings, wishlist, plants to watch, seasonal rotation.
— FULL CARE HISTORY
Every watering, every fertilizer, every repot — logged with notes. See your plant's complete care timeline at a glance and spot patterns before problems start.
— FREE TO START, PREMIUM WHEN YOU'RE READY
Blackthumb is free to download. Start tracking your plants immediately. Upgrade to Premium for unlimited plants, unlimited locations, all reminder types, and the Light Score Calculator.
Built for people who kill plants — and want to stop.
https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
the app is great but many common flows like recording light etc take way too many clicks and hopping between UIs. the app needs a UX designer touch. happy to revisit the rating hopefully soon when they got fixed.
Developer Response
Thank you for the feedback. UI is definitely something we are actively working on. Hope you stick with us while we improve.- Lee & Cal.
Essential app for plant hobbyists!
Toolovesyou
These are the types of developers we need to support!!This app has it all! There’s reminders and logs for fertilization, watering, repotting, pest treatments, and tons of other stuff! It also has a built-in light meter, and details about how much light each plant in your collection needs. It will give you advice based on your inputs! I have been using it for 1 day and have already made changes in where my plants live in my house.Very impressive and intuitive with many functionalities, all in one user-friendly app :) Usually to get these tools you have to download separate apps for each one or different physical products! Also, two weeks free for the light insights is really really cool. It keeps this knowledge accessible to all plant hobbyists at any level and breaks the idea that you need expensive tools to grow your plants well. Good on the developers <3 I will recommend this to all plant lovers I know!
Developer Response
Thank you so much, we're glad your enjoying the app so far.-Lee & Cal
Great app by a great dude
Wok The Builder
Love the videos. Wish there wasn’t a paywall for the light reading, but it’s not that bad and I totally get why you have it.
Horrible
aryankapur88@
Don’t use all good things locked behind a payway 1 starrrrr
## Select last watering date when adding new reminder
## Increased DLI meter accuracy
## UI fixes
Version 1.2.1
The developer, Lee Griffith, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
Seller
Lee Griffith
Size
64 MB
Category
Lifestyle
Compatibility
Requires iOS 15.1 or later.
iPhone Requires iOS 15.1 or later.
iPad Requires iPadOS 15.1 or later.
iPod touch Requires iOS 15.1 or later.
Mac Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.
