App comparisons — your questions answered

Growli is the broadest fit for beginners because it handles identification, watering reminders, symptom diagnosis, and daily seasonal briefings in one conversational interface — there's no learning curve to figure out which feature to use when. Greg is a strong simpler alternative if your collection is small and indoor-only. PictureThis is the easiest pure identifier.

Growli's free core tier (identification + basic care) is the most useful free tier for active gardeners. The Old Farmer's Almanac is free with a small premium tier and is excellent for US weather and planting calendars. PlantNet is genuinely free for raw plant identification, though it doesn't include ongoing care features.

Growli is the only app on this list with native RHS hardiness rating support, UK Met Office weather data, and frost dates calibrated to UK regions. Most other gardening apps are US-leaning, which means UK gardeners spend time mentally converting USDA zones and US frost dates. If you garden in the UK, install Growli first.

From Seed To Spoon is the deepest US vegetable planning app, with companion planting, crop rotation, and frost-date-aware sowing schedules. Growli is more general-purpose but handles vegetables alongside ornamentals and indoor plants — better if you want one app rather than several.

Yes — Growli is built as a combined identifier plus AI gardening assistant. After identification you can ask follow-up questions, log your watering, get a daily morning briefing with weather and tasks, and receive frost alerts. PictureThis and Greg each cover part of this, but Growli is the only one combining all three in a conversational interface.

PictureThis has the largest trained species catalogue and is consistently strongest on ornamentals and houseplants. PlantNet (covered in our plant identifier comparison) is the strongest free option, especially for wild and native species. Growli's identification matches PictureThis on common species and is improving monthly on the long tail.

Try the free tiers first. For most home gardeners, the free tier of Growli plus the free tier of PictureThis or PlantNet covers 80% of what you'll need. Pay for a subscription only if you find yourself blocked by paywalls on features you actually use — most often that's symptom diagnosis (Growli Plus), advanced light measurement (Planta), or unlimited identifications (PictureThis).

For most common houseplant problems and standard vegetable timing, yes — modern AI gardening apps match expert recommendations from horticulture extension services for the typical case. For commercial-scale damage, suspected viral or fungal outbreaks across multiple plants, or unusual species, your local university extension service or the RHS Advisory in the UK will catch nuances an app misses. Growli is calibrated to recommend escalation when confidence is low.

It depends on the job. For pure watering schedules and a polished reminder UI, Planta leads. For AI-driven care advice on a smaller collection, Greg is strong. For a full assistant that combines reminders, conversational symptom diagnosis, a daily morning briefing, frost alerts, and native US + UK localization, Growli is built for that. Most growers run one care app plus one identifier.

Yes. Vera by Bloomscape is free end-to-end as a Bloomscape marketing channel, and Growli has a genuinely usable free core tier covering identification, basic care reminders, and single-plant logs. PlantNet (an identifier rather than a care app) is also completely free. Most other plant care apps offer a trial period and then convert to a paid subscription.

Vera by Bloomscape and Growli's free core tier are the two most credible fully free options for ongoing plant care in 2026. Vera leans on a curated species library and reminders; Growli's free tier covers identification and basic reminders, with conversational diagnosis and frost alerts on the paid Plus plan. PlantNet is the strongest free identifier if care features are not required.

For watering reminders and species-specific guidance, yes — most apps reliably nudge users to water on schedule and prevent the most common overwatering or underwatering mistakes. For symptom diagnosis, results vary widely. Static FAQ-style diagnosis (used by most apps) misses cases because overwatering, light stress, and pests overlap visually. Conversational diagnosis (used by Growli) narrows causes by asking clarifying questions and tends to land closer to the right answer.

Add each plant to the app with its species, pot size, and light conditions, then follow the watering and feeding schedule the app generates. Photograph any symptoms as they appear so the diagnostic flow has visual context. With Growli specifically, the daily morning briefing surfaces the tasks for that day across the whole collection, and frost alerts arrive 24 to 48 hours ahead of cold nights for outdoor pots.

Vera by Bloomscape is the most complete fully free plant care app in the US — funded as a marketing channel rather than a subscription product. Growli has a free core tier covering identification and basic reminders, with paid features for conversational diagnosis, frost alerts, and offline mode. Genuinely free apps are rare in the category because adaptive scheduling and AI care advice carry real compute cost.

Most plant care apps are houseplant-first and treat outdoor gardens as an afterthought. Growli covers both — indoor and outdoor, US or UK — with native frost alerts for outdoor pots and beds, USDA zone and RHS hardiness rating support, and weather-aware reminders. From Seed to Spoon is the specialist for US vegetable gardens. For mixed collections, Growli is built for that case.

It depends on the job. For pure watering schedules and a polished reminder UI, Planta leads at around £35-40 per year. For AI-driven care advice on a smaller indoor collection, Greg is strong at £30-35 per year. For official RHS advice, RHS Grow is the canonical UK option (free basics or £58 RHS membership). For a full assistant that combines reminders, conversational symptom diagnosis, a daily morning briefing, frost alerts, and native UK localisation with RHS hardiness ratings, Growli is built for that at around £24 per year. Most UK gardeners run one care app plus one identifier.

Yes. RHS Grow has a usable free tier funded by the Royal Horticultural Society as part of its public-facing services. Growli has a genuinely usable free core tier covering identification, basic care reminders, and single-plant logs. PlantNet (an identifier rather than a care app) is also completely free. Most other plant care apps offer a trial period and then convert to a paid subscription.

RHS Grow basic tier and Growli's free core tier are the two most credible fully free options for ongoing plant care in 2026 for UK gardeners. RHS Grow leans on the RHS's curated species library and reminders; Growli's free tier covers identification and basic reminders, with conversational diagnosis and UK frost alerts on the paid Plus plan. PlantNet is the strongest free identifier if care features are not required.

For watering reminders and species-specific guidance, yes — most apps reliably nudge users to water on schedule and prevent the most common overwatering or underwatering mistakes in UK conditions. For symptom diagnosis, results vary widely. Static FAQ-style diagnosis (used by most apps) misses British-specific cases like the autumn central-heating shock, peat-free compost behaviour, and UK tap-water fluoride damage. Conversational diagnosis (used by Growli) narrows causes by asking clarifying questions and tends to land closer to the right answer for UK plants.

Add each plant to the app with its species, pot size, UK light conditions (north-facing window, sash-window draught, central-heating proximity), then follow the watering and feeding schedule the app generates. Photograph any symptoms as they appear so the diagnostic flow has visual context. With Growli specifically, the daily morning briefing surfaces the tasks for that day across the whole British collection, and UK frost alerts arrive 24 to 48 hours ahead of cold nights for outdoor pots.

RHS Grow is the official UK-native app from the Royal Horticultural Society, with native British species coverage and RHS hardiness ratings. Growli has native UK localisation built in from launch — RHS hardiness ratings, British weather and frost forecast integration, peat-free compost guidance, and UK retailer references (B&Q, Patch Plants, RHS Plants, Dobbies, Notcutts). Most other apps are US-leaning and require manual translation of advice.

Most plant care apps are houseplant-first and treat outdoor gardens as an afterthought. Growli covers both — UK indoor and outdoor — with native frost alerts for outdoor pots and beds tuned to the British forecast, RHS hardiness rating support, and UK weather-aware reminders. RHS Grow is the specialist for traditional British garden plants. For mixed UK collections, Growli is built for that case — created by Justas Macys and Nojus Balčiūnas to handle the specific British failure modes (central heating, peat-free compost, late frosts) that US-leaning competitors miss.

It depends on the job. For raw species identification, PictureThis leads on catalogue size and PlantNet leads on free, science-backed accuracy. For ongoing plant care and symptom diagnosis, Growli is built around conversational follow-up — describe symptoms in plain English, get a ranked diagnosis, and receive a daily morning briefing. Most growers end up running one identifier (PictureThis or PlantNet) and one care assistant (Growli or Greg).

PictureThis and PlantNet are the two strongest in 2026. PictureThis has the larger trained catalogue and a faster, more polished UX, but locks most features behind a subscription. PlantNet is free, open-source, and backed by a French research consortium — it is particularly strong on wild and native species. For cultivated houseplants, PictureThis still edges ahead on accuracy.

PlantNet is the strongest fully-free option. It is backed by a citizen-science research consortium, has no paywall or ads, and is transparent about confidence scores. Seek by iNaturalist is also free and better for biodiversity logging. Growli has a free core tier covering identification and basic care, with conversational diagnosis on the paid plus plan.

Growli is built specifically for symptom diagnosis. Photo-only apps return a species name and a static FAQ page; Growli asks clarifying questions — soil moisture, recent repot, watering history, light conditions — and ranks the most likely cause by your specific answers. PictureThis and Greg have diagnostic features but neither supports a multi-turn dialog.

Growli leads on disease and symptom diagnosis because it treats it as a conversation rather than a single photo lookup. Common causes — overwatering, light, pests, fungal disease — overlap visually, so a multi-turn dialog matters more than the photo itself. For commercial-scale or fast-spreading disease, escalate to your local university extension service or the RHS Advisory.

PictureThis is strongest on ornamental flowers and cultivated varieties thanks to a larger trained catalogue. PlantNet edges ahead on wild flowers and native species because of its research-grade citizen-science dataset. For mixed use — flowers in your garden plus the care that goes with them — Growli combines identification with seasonal advice tied to your climate.

PlantNet is the most credible option for trees and woody plants in the wild, with strong species coverage and conservative confidence scores. Seek by iNaturalist is a close second and feeds your observations into a real biodiversity database. PictureThis is faster but more focused on garden ornamentals than forest species.

Yes — Growli is built as a combined identifier plus AI gardening assistant. After identification you can ask follow-up questions, log your watering, get a daily morning briefing with weather and tasks, and receive frost alerts ahead of cold nights. PictureThis and Greg each cover part of this, but Growli is the only one combining all three in a conversational interface.

It depends on the job. For raw species identification, PictureThis leads on catalogue size at around £24.99 a year, and PlantNet leads on free, science-backed accuracy for British wild plants. For RHS-aligned UK gardening, RHS Grow is the official option. For ongoing plant care and symptom diagnosis with native UK localisation (RHS hardiness ratings, British weather, central-heating context), Growli is built for that. Most UK gardeners end up running one identifier (PictureThis, PlantNet or RHS Grow) plus one care assistant (Growli or Greg).

PictureThis is approximately £24.99 GBP per year on annual billing after the 7-day free trial in the UK App Store and Google Play UK, or roughly £6.99 per month on monthly billing. Pricing varies by region and promotional offers. By comparison, Growli Plus is approximately £24 per year, Greg Plus is approximately £30-35, and PlantNet and Seek are free.

PlantNet is the strongest fully-free option for UK gardeners. It is backed by a French research consortium (Cirad, INRA, INRIA, IRD), has no paywall or ads, is transparent about confidence scores, and is strong on European native species. Seek by iNaturalist is also free and better for UK biodiversity logging. RHS Grow has a free tier with limited features. Growli has a free core tier covering identification and basic care, with conversational diagnosis on the paid Plus plan.

Yes if you are already an RHS member — RHS Grow is included with membership and is the strongest UK-native option for advice on British natives, garden ornamentals, hedgerow species and traditional UK varieties. It includes the official RHS hardiness rating system and a ChatBotanist feature for member questions. If you are not an RHS member, the free tier is still useful for UK plant ID, but the full feature set requires the £58 per year RHS membership.

Growli is built specifically for symptom diagnosis with native UK localisation. Photo-only apps return a species name and a static FAQ page; Growli asks clarifying questions — compost moisture, recent repot, watering history, light conditions, central-heating switch-on date — and ranks the most likely cause by your specific answers. PictureThis and Greg have diagnostic features but neither supports a multi-turn dialog tuned to British conditions like the autumn central-heating shock or peat-free compost behaviour.

PlantNet is the most credible option for British wild flowers, hedgerow species, and trees thanks to a research-grade dataset built on European citizen-science records. RHS Grow is the official UK option and is particularly strong on garden ornamentals and British natives. Seek by iNaturalist is a close third and feeds your UK observations into iRecord and similar biodiversity databases. PictureThis is faster but more focused on garden ornamentals than wild species.

Yes — Growli is built as a combined identifier plus AI gardening assistant with native UK support. After identification you can ask follow-up questions in plain English, log your watering, get a daily morning briefing with British weather and tasks, and receive frost alerts ahead of cold nights tuned to the UK forecast. PictureThis and Greg each cover part of this, but Growli is the only one combining all three in a conversational interface with RHS hardiness ratings and UK retailer references.

Different jobs. RHS Grow is the official RHS app and is strongest on official RHS advice, British native species, and member benefits — best for traditional UK garden questions. Growli is a conversational AI assistant designed for symptom diagnosis, daily morning briefings, and frost alerts across a mixed indoor and outdoor collection — best when you want a back-and-forth dialog rather than an article. Many British growers run both: RHS Grow for official advice, Growli for in-the-moment diagnosis and reminders. Growli is built by Justas Macys and Nojus Balčiūnas with native RHS hardiness rating support, not bolted on.

The fastest route is a photo identification app — PictureThis, PlantNet, or Growli will return a species name in under five seconds on common houseplants with around 90 percent accuracy. If the result looks off, cross-check by leaf shape, growth habit, and any flowers, and post a photo to r/whatsthisplant for a human second opinion. Growli combines all three steps by asking one or two clarifying questions in the identification dialog, which catches cultivar and juvenile-form errors that single-shot apps miss.

For pure species identification on common houseplants, PictureThis has the largest catalogue and the fastest UI but locks features behind a paid subscription. PlantNet is the best free option and is credible on the most common indoor species. Growli is the best choice if you want identification plus a conversational care plan — it asks follow-up questions when the model is uncertain rather than guessing confidently. Most experienced growers run one identifier and one care app side by side.

Yes. PlantNet is fully free with no paywall and is the strongest free identifier on the market. Seek by iNaturalist is also free, but it is intentionally conservative on cultivated varieties and is better for wild species. Growli has a free core tier that covers identification and basic care; its conversational diagnosis and weather features sit on the paid plus plan. Posting to r/whatsthisplant on Reddit is also free and often returns a confident answer within an hour.

Three common reasons. First, the plant is a cultivar — variegated pothos, Thai constellation monstera, Pink Princess philodendron — and the app has only been trained on the green parent species. Second, the plant is juvenile and looks different from the mature form the app has learned. Third, two species genuinely look similar — pothos and heartleaf philodendron are the most common confusion. A conversational app like Growli handles these by asking one or two clarifying questions before locking in an answer.

Both have heart-shaped leaves on trailing vines, which is why apps confuse them. Pothos leaves are thicker, waxier, and often variegated with cream or yellow. Philodendron leaves are thinner, softer, and uniformly green with a more matte finish. Pothos has a textured upper surface; philodendron is smoother. Heartleaf philodendron also shows visible aerial roots at every node, whereas pothos has more subtle nubs. If you cannot tell from a photo, snap a leaf side by side with a coin and run Growli's conversational identifier.

Often, yes. Photo apps can identify roughly 80 percent of common houseplants from a single clear leaf shot if the lighting is good and the leaf is in focus. Accuracy improves dramatically if you also capture the growth habit (trailing, upright, rosette), the underside of the leaf, and any flowers or fruit. Single-leaf identification fails most often on succulents and air plants where many species share near-identical leaf shapes.

Pothos versus heartleaf philodendron is the single most common mix-up, including by paid apps. Pothos has thicker, waxier leaves often variegated with cream; philodendron is thinner, softer, and uniformly green with prominent aerial roots. The second most common confusion is between juvenile monstera and philodendron, since young monstera leaves are unsplit hearts. Apps that ask one clarifying question — Growli does this — catch both cases reliably.

Not always. A 99 percent confidence with no alternatives offered is a UX choice, not necessarily an accuracy claim. PlantNet and Growli both surface alternative matches when the model is uncertain, which is usually more useful than false certainty. If the answer looks wrong against the visual cues you can see — leaf shape, vein pattern, growth habit — run a second app and post to r/whatsthisplant before committing to a care plan.

Yes. PlantNet is the leading fully-free PictureThis alternative. It's run by a French research consortium (Cirad, INRA, INRIA, IRD), uses citizen-science contributions to train its model, and has no paywall, no ads, and no nag-screens. Seek by iNaturalist is another fully-free option, better suited to biodiversity logging than houseplant care. Growli also offers a free core tier covering identification and basic care.

PictureThis has a free trial but is not a free app in practice. Most useful features — unlimited identifications, disease diagnosis, care reminders — sit behind a subscription of roughly $30 USD or £25 GBP per year. The free trial converts to a paid subscription automatically and many users report being charged unexpectedly. If you want a fully free alternative, PlantNet is the cleanest option.

PictureThis is typically around $29.99 USD or £24.99 GBP per year on annual billing, with monthly options usually around $7-8 USD. Pricing varies by region and promotional offers. By comparison PlantIn and Growli sit at roughly the same annual price point, Greg Premium is closer to $40 per year, Planta around $36, and PlantNet and Seek are free.

Deleting the PictureThis app does not cancel your subscription — billing continues. To cancel, open your phone's subscription settings. On iPhone: Settings → your name → Subscriptions → PictureThis → Cancel. On Android: Play Store → profile icon → Payments and subscriptions → Subscriptions → PictureThis → Cancel. Cancel before switching to an alternative or you'll pay for both apps in parallel.

PictureThis is reliable on common species and ornamentals — its trained catalogue is among the largest in the market. It is less reliable on similar-looking cultivated varieties and hybrids, where it sometimes returns a confident answer that turns out to be a sibling species. For wild and native species PlantNet is often more reliable because it shows confidence scores and alternative matches. For symptom diagnosis, no photo-only app is reliable without follow-up questions — which is why Growli's multi-turn dialog exists.

They solve different jobs. PictureThis is better for cultivated houseplants, garden ornamentals, and quick identification with a polished UI — at the cost of a paid subscription. Seek by iNaturalist is better for wild species, biodiversity logging, and citizen science — and it is free and family-friendly. For indoor plant care neither is ideal; consider Growli or Greg instead.

Yes — Growli is built as a combined identifier plus AI gardening assistant. After identification you can ask follow-up questions in plain English, log your watering, receive a daily morning briefing with weather and tasks, and get frost alerts before cold nights. PictureThis and Greg each cover part of this, but Growli is the only one combining all three jobs in a conversational interface with native US + UK localization.

Yes. PlantNet is the leading fully-free PictureThis alternative for UK users. It is run by a French research consortium (Cirad, INRA, INRIA, IRD), uses citizen-science contributions to train its model, and has no paywall, no ads, and no nag screens. Seek by iNaturalist is another fully-free option, better suited to UK biodiversity logging than houseplant care. RHS Grow has a free tier with limited features. Growli also offers a free core tier covering identification and basic care.

PictureThis has a 7-day free trial but is not a free app in practice. Most useful features — unlimited identifications, disease diagnosis, care reminders — sit behind a subscription of approximately £24.99 GBP per year in the UK App Store. The free trial converts to a paid subscription automatically and many UK users report being charged unexpectedly. If you want a fully free alternative, PlantNet is the cleanest option.

PictureThis is typically approximately £24.99 GBP per year on annual billing in the UK, with monthly options usually around £6.99 GBP. Pricing varies by region and promotional offers. By comparison, PlantIn and Growli Plus both sit at roughly £24 per year, Greg Plus is closer to £30-35, Planta Premium is approximately £35-40, RHS Grow is free basics or £58 RHS membership, and PlantNet and Seek are completely free.

Deleting the PictureThis app does not cancel your subscription — billing continues. To cancel, open your phone's subscription settings. On iPhone: Settings → your name → Subscriptions → PictureThis → Cancel. On Android: Play Store → profile icon → Payments and subscriptions → Subscriptions → PictureThis → Cancel. Cancel before switching to an alternative or you will pay for both apps in parallel — a common UK mistake.

PictureThis is reliable on common UK species and ornamentals — its trained catalogue is among the largest in the market and includes substantial European data. It is less reliable on similar-looking cultivated varieties and hybrids, where it sometimes returns a confident answer that turns out to be a sibling species. For wild and native British species PlantNet is often more reliable because it shows confidence scores and alternative matches, and RHS Grow is the strongest UK-native option. For symptom diagnosis, no photo-only app is reliable without follow-up questions — which is why Growli's multi-turn dialog exists.

They solve different UK jobs. PictureThis is better for cultivated houseplants, garden ornamentals, and quick identification with a polished UI — at the cost of a paid subscription. Seek by iNaturalist is better for British wild species, biodiversity logging on country walks, and citizen science — and it is free and family-friendly. For indoor UK plant care neither is ideal; consider Growli or RHS Grow instead.

Growli is built specifically for this. PictureThis returns a species name and a static FAQ page; Growli asks clarifying questions — compost moisture, recent repot, watering history, central-heating switch-on date — and ranks the most likely cause by your specific answers and UK region. Static FAQ-style diagnosis misses British-specific causes like the autumn central-heating shock, peat-free compost behaviour, and UK tap-water fluoride damage on calatheas.

Yes — Growli is built as a combined identifier plus AI gardening assistant with native UK support. After identification you can ask follow-up questions in plain English, log your watering, receive a daily morning briefing with British weather and tasks, and get frost alerts before cold nights tuned to the UK forecast. PictureThis and Greg each cover part of this, but Growli is the only one combining all three jobs in a conversational interface with native RHS hardiness ratings and UK retailer references. Built by Justas Macys and Nojus Balčiūnas as the British-aware alternative to US-leaning competitors.

Yes — PlantNet is completely free, ad-free, and has no paywall or in-app purchases. It is run as a non-profit citizen-science project by a French research consortium (Cirad, INRA, INRIA, IRD) and funded through institutional and research-grant support. There is no premium tier and no auto-renewal trap. By contrast, PictureThis charges roughly $30 USD per year after a free trial.

PictureThis has a free trial but is not a free app in practice. Most genuinely useful features — unlimited identifications, disease diagnosis, care reminders — sit behind a subscription of roughly $30 USD or £25 GBP per year. The free trial converts to a paid subscription automatically, and many users report being charged unexpectedly. If you want a fully free alternative with comparable identification quality, PlantNet is the cleanest option.

PictureThis is typically around $29.99 USD or £24.99 GBP per year on annual billing, with monthly options usually around $7-8 USD. Pricing varies by region and promotional offers. PlantNet is free with no paid tier. Growli has a free core tier and a paid plus tier at a comparable annual price point to PictureThis but built around conversational care rather than identification alone.

PictureThis is reliable on common cultivated species and garden ornamentals — its trained catalogue is among the largest in the market. It is less reliable on similar-looking hybrids and cultivars, where it sometimes returns a confident answer that turns out to be a sibling species. PlantNet is often more reliable on wild and native species because it shows ranked candidates with confidence scores rather than a single answer. For symptom diagnosis, no photo-only app is fully reliable without follow-up questions — which is why Growli's multi-turn dialog exists.

Yes — PlantNet is one of the strongest plant ID apps for trees and woody plants. The citizen-science dataset behind it includes extensive tree imagery contributed by researchers and amateur botanists, and PlantNet returns ranked candidate species with confidence scores rather than a single guess. It handles bark, leaf, flower, and fruit photos and supports multi-organ submissions for harder identifications. For garden ornamentals and cultivated trees, PictureThis can be more specific on cultivar names.

No — PlantNet is identification-only and does not include a disease or symptom diagnosis layer. PictureThis offers a paid disease-identification feature, but it is still a photo lookup rather than a dialog, and it cannot ask the clarifying questions (watering history, light, recent repot) that distinguish visually similar causes such as overwatering, root rot, and fungal disease. For symptom diagnosis specifically, a conversational tool such as Growli is a better fit than either app.

PlantNet is better for wild plants. Its dataset is built from outdoor citizen-science observations of native species, weeds, wildflowers, and trees, and it is backed by a French research consortium with peer-reviewed credibility. PictureThis is stronger on cultivated houseplants, garden ornamentals, and hybrid cultivars. If your photographing happens mostly outdoors and away from gardens, PlantNet is the credible choice — and it is free.

Yes — Growli is built as a combined identifier plus AI gardening assistant. After identification you can ask follow-up questions in plain English, log your watering, receive a daily morning briefing with weather and tasks, and get frost alerts before cold nights. PictureThis and PlantNet are both excellent at identification, but neither offers conversational follow-up or weather-integrated care guidance. Many growers run PlantNet for free wild-plant ID and add Growli for the ongoing care of plants they already own.

Growli is the strongest single-app choice for diagnosis because it asks clarifying questions in dialog — soil moisture, watering history, recent changes — and ranks the most likely cause by your specific answers. PictureThis is faster for identification but its diagnosis layer is a static FAQ rather than a dialog. greg.app offers a community angle that catches edge cases but takes hours. For symptoms that overlap visually (yellow leaves, drooping, brown tips), the dialog is what separates the causes.

Growli has a free core tier covering identification and basic care; the conversational diagnosis sits on the paid plus plan at around $30 USD / £24 GBP per year. PictureThis offers a 7-day free trial that converts to a paid subscription around $29.99 USD per year. greg.app has a free tier with limited features and Super Greg at around $29.99 USD per year. PlantNet is fully free but does not include a diagnosis layer at all. If budget is the top constraint, posting to r/houseplants on Reddit is free and often returns useful answers within an hour.

Partly. A photo is enough to diagnose unambiguous symptoms — visible pests, powdery mildew, scorched leaves, advanced root rot. It is not enough to separate the most common overlapping causes — overwatering versus underwatering versus light stress all show similar yellowing patterns. That is why dialog-based apps like Growli ask about watering history, soil feel, and recent changes before committing to an answer. A confident single-photo diagnosis on a yellow leaf should be treated as a guess.

PictureThis identifies the species and then shows a static FAQ page of common issues for that species. If your problem is in that FAQ, the answer is fine; if not, the app cannot go deeper. Growli treats diagnosis as a conversation — it asks two or three clarifying questions about soil moisture, watering history, and recent changes, then ranks the most likely causes by probability. The dialog handles the visually overlapping symptoms that single-photo apps cannot reliably separate.

Overwatering, by a wide margin. Roughly half of all houseplant deaths come from chronically wet soil and the root rot that follows. The symptom — yellow lower leaves and droopiness — is often mistaken for underwatering, which leads people to water more and accelerate the problem. A diagnosis app that asks about watering history rather than just looking at the leaf catches this pattern reliably. See our [overwatered vs underwatered](/blog/overwatered-vs-underwatered) guide for the visual difference.

For most houseplant problems, an app is faster, cheaper, and accurate enough. For commercial-scale issues, fast-spreading disease, or rare collector plants, escalate to a human — a local university extension service in the US, the RHS Advisory in the UK, or a specialist nursery. The app and the human are complementary: use the app for the initial triage, then escalate if the plant is valuable enough or the diagnosis is genuinely ambiguous.

Days to weeks, depending on the cause. Underwatered plants often perk up within hours of a deep drink. Overwatered plants take a week or more once you let the soil dry and trim damaged roots. Pest treatments usually need 7 to 14 days and a second application. Frost or transplant shock can take a full season to outgrow. Set a 7-day check-in and re-photograph the plant — if symptoms are stable or improving, the diagnosis was right; if worse, re-run the dialog with the new context.