“Free plant app” can mean four different things: fully free, free download with limited tools, a permanent scan allowance, or a short subscription trial. Those are not equivalent.
Disclosure: PlantGrail publishes this guide and makes PlantGrail - AI Plant Scanner. Features and US prices were checked against official App Store listings on October 15, 2026. Offers differ by device, country, and date.
What is actually free?
| App or tool | Free model | Best use | Important limit |
|---|---|---|---|
| PlantNet | Free app | Identifying plants and contributing observations | Not a disease diagnosis or reminder app |
| PlantGrail web plant doctor | Free web tool | Symptom-based diagnosis starting point | Does not inspect a photo |
| PlantGrail - AI Plant Scanner | 3 free AI scans that never expire, plus 3 free follow-up questions per result | Photo diagnosis and identification, follow-up questions, My Garden, care calendar | Premium $7.99/month or $39.99/year after a 7-day free trial |
| PictureThis | Free download with paid features/offers | Identification and broad care suite | Verify current trial and renewal screen |
| Planta | Free download with premium features | Schedules and collection care | Advanced tools and plans may require subscription |
| Greg | Free download with premium plan | Watering guidance and community | Official listing describes an annual plan and trial |
Best fully free identifier: PlantNet
PlantNet is the most defensible answer when “free” means no care subscription. It identifies plants, supports citizen-science observations, maps findings, and can capture images offline for later identification.
Its boundary is equally important: PlantNet is not a houseplant diagnosis or care-scheduling product. Use it to answer “what is this?” rather than “why are these leaves turning yellow?”
Best free diagnosis starting point: PlantGrail’s web tool
The PlantGrail web plant doctor is free and does not require a login. It asks about symptoms and ranks plausible causes from the information you provide.
Because it is not analyzing a camera image, you need to describe the evidence accurately. Check leaf position, soil moisture, lesion texture, pest signs, and recent care changes before choosing an answer.
Best permanent app allowance: PlantGrail - AI Plant Scanner
PlantGrail - AI Plant Scanner includes three free AI scans that do not expire, and you can start scanning without any setup. Each result also comes with three free follow-up questions about that plant. It is a limited permanent allowance, not an unlimited-free promise. Premium is $7.99 per month or $39.99 per year with a 7-day free trial (US App Store, October 15, 2026), and adds unlimited scans and 100 follow-up questions per month.
Three scans are useful for testing whether the workflow helps you gather better evidence. They are not intended to replace a free identification database or an unlimited reminder system.
Free download is not the same as free care
PictureThis, Planta, Greg, PlantIn, Plantum, and Blossom can all be downloaded without paying upfront. Their listings also show in-app purchases or subscription plans. A product may allow a limited action, show a trial, or reserve major features for premium access.
Before accepting a trial:
- Read the trial duration on the final Apple purchase sheet.
- Note the renewal price and billing period.
- Check whether the feature you need is included before subscribing.
- Set a reminder before the trial ends if you are still evaluating.
- Do not assume deleting the app cancels a subscription.
Best free app by job
I need to identify a mystery plant
Start with PlantNet. Use multiple photos, including flowers, leaves, stem, and overall habit when available. A common houseplant cultivar may still need confirmation against a reliable botanical source.
My plant is sick
Start with the free PlantGrail diagnosis tool. If you want a photo-based check, use one of the three free scans in PlantGrail - AI Plant Scanner.
I forget to water
A phone calendar or free reminder app can be enough. Set a reminder to check the plant, not automatically water it. Fixed watering dates cause trouble when light, temperature, pot size, or season changes.
I want a complete collection system
Expect premium tradeoffs. Planta, PictureThis, Greg, and similar products invest in schedules, profiles, community, and ongoing services. Compare the current free limits and annual cost rather than searching for an unlimited product that may not exist.
Privacy still matters in a free app
An app can cost nothing while collecting data. Review the Apple privacy section for tracking, linked data, location, photos, identifiers, and usage. Apple notes that these labels are supplied by the developer and are not verified by Apple, so treat them as disclosure rather than an audit.
PlantGrail’s “no account required” statement means you can start without creating an account. It does not mean no technical or diagnostic data is processed.
Frequently asked questions
Is PictureThis completely free?
It is free to download, but its App Store listing includes paid plans and in-app purchases. The exact free experience and trial offer can change.
Is Planta free?
Planta is free to download and offers premium plans. Check which schedule, diagnosis, and collection features are available in the current free tier on your device.
Is there a free app with unlimited diagnosis?
We did not find a defensible unlimited diagnosis promise among the major products reviewed. PlantNet is unlimited for identification, which is a different task. PlantGrail’s web symptom tool is free, and the PlantGrail app includes three free AI scans that do not expire.
Can I trust a free diagnosis?
Price does not determine accuracy. Trust depends on whether the relevant evidence is visible, the app explains uncertainty, and you verify the result before treatment.
Continue comparing plant apps
- Start with the complete plant care app comparison.
- Compare plant identification apps with care tips when naming the plant is the first job.
- Compare plant community and care-tracking apps when reminders, journaling, or discussion matter most.
- Read the plant diagnosis app comparison for sick-plant workflows and their limits.
Bottom line
Use PlantNet when you need free identification, PlantGrail’s web tool when you need a free diagnostic starting point, and the PlantGrail app when you want photo scans with follow-up questions and a clear three-scan free allowance. Treat trials as paid products with a delayed first charge, and always verify what the checkout screen says.