How we source & fact-check our plant data

Our data sources

• Pet toxicity — the ASPCA Toxic and Non-Toxic Plants database, cross-checked against the Pet Poison Helpline, NC State Extension and the Merck Veterinary Manual where a species is not individually listed.
• Cold hardiness — the USDA Plant Hardiness Zone Map (1991–2020 normals) and the RHS hardiness rating system.
• Care (light, water, soil, humidity) — US university Extension services (Missouri, Illinois, Penn State, UF/IFAS, NC State and others) and the Royal Horticultural Society, supplemented by established horticultural references.
• Our catalogue — 8,452 structured species records compiled and maintained by the Growli editorial team, the basis for our open data studies.

How we fact-check

Evergreen botanical facts (the light and water preferences of well-known houseplants, basic plant biology) can rely on established horticultural knowledge. But every specific claim — a cultivar name, a statistic, a study citation, a regulatory fact, a toxicity verdict, a UK-localised detail — is verified against an authoritative source (a .gov, .edu, the RHS, ASPCA or USDA) before it ships. If a number cannot be confirmed, we soften the language (“typically”, “in many regions”) rather than invent a figure.

How we check what we publish

Specific claims are checked against a primary source before publishing: cultivar names, prices, statistics, dates, regulatory facts and competitor features. The source depends on the kind of claim.

• Pet toxicity comes from the ASPCA. Where the ASPCA or another source is ambiguous about a species, the page says “check with your vet” rather than asserting that the plant is safe.
• Edibility comes from the USDA or university extension services.
• UK content is checked against UK sources, including the Royal Horticultural Society, rather than US ones.
• App prices, ratings and features are read from each app's own App Store listing, and the page states the date they were read. We have not run a hands-on accuracy test of plant apps, so we do not rank them by accuracy. Where a listing does not mention a feature, we say “not on its listing” rather than claiming the app lacks it.
• Our own figures are quoted exactly as our studies state them. For example, our houseplant toxicity study found that 63.8% of the 5,561 species it analysed are harmful to pets, using ASPCA-sourced classifications.

Conflict of interest. We make Growli. Every article that compares Growli with other plant apps says so near the top, so you can weigh what follows with that in mind. See the note on our about page.

Authorship. Articles are signed “Growli editorial team”. We do not attribute content to a fictitious single author, and we do not list reviewers, horticulturists or vets who do not exist.

The pet-safety gate

Toxicity is the claim we treat most strictly, because a wrong “pet-safe” label can put an animal at risk. Our classifications are grounded in the ASPCA database. Where the ASPCA lists a genus by name (for example “Begonia spp.”), we apply that verdict across the species in our catalogue belonging to that genus — consistent with how the ASPCA itself frames genus-wide toxicity. Where only a representative species is listed, we extend the verdict across the genus only when the shared plant chemistry is corroborated by Extension or veterinary sources. A species is never marked pet-safe on assumption: every record passes an automated genus-level safety gate that forces a toxic classification for any plant family with a known toxic principle, and our “mildly toxic” tier flags species likely to cause mild gastrointestinal upset rather than systemic harm. Always confirm an individual plant at aspca.org or with a veterinarian before assuming it is safe.

Corrections & updates

Plant taxonomy and toxicity guidance change. We revise records as sources update, and we welcome corrections. If you spot something that conflicts with an authoritative source, email hello@getgrowli.app or use the contact page. We fix it, and we update the page's “updated” date only when the content really changes, never to make a page look fresher than it is.