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Indoor Plant Care
Sources & methodology

Where our houseplant facts come from

Every claim on indoorplantcare.com cites a primary horticultural, veterinary, or governmental source. The list below covers every domain we cite, why each is authoritative, and what we use it for.

If you find a claim on this site that contradicts one of these sources, please let me know and I will correct it within 7 days and bump the article’s last-reviewed date.

Our editorial process

  1. Source first. Before drafting a new article, we identify the primary source for every factual claim we expect to make. If we can’t find a primary source, we don’t write the claim.
  2. Quote conservatively. Where sources disagree (common with light or watering recommendations), we note the disagreement explicitly rather than picking one and pretending it’s settled.
  3. AI-assisted drafting. Guides are researched and drafted with AI tools. They are not based on first-hand growing experience, and AI output is never treated as a source: every factual claim has to cite a primary source.
  4. Re-check on publish. Every URL is opened and verified on the day of publication. The article’s footer shows the fact-check date.
  5. Fact-check pass and corrections. On October 12, 2026, every guide was checked against the sources it cites and corrected where it was wrong; corrected guides show that date. There is no fixed re-check schedule. When a reader reports an error, we check it against the source, correct the page and update its date.

Primary sources we cite

American Society for the Prevention of Cruelty to Animals

aspca.org

Used for: Pet-toxicity classifications (cats, dogs, horses). Where the ASPCA has an entry for a plant, species and answer pages cite it directly; where it has none, the page names the other source it used, usually NC State Extension.

Why authoritative: ASPCA Animal Poison Control Center is the most-cited veterinary toxicology resource in North America, operated by board-certified veterinary toxicologists. The Toxic and Non-Toxic Plants database is the standard reference for vet clinics and pet poison hotlines.

Visit American Society for the Prevention of Cruelty to Animals

North Carolina State Extension Plant Toolbox

plants.ces.ncsu.edu

Used for: Botanical nomenclature, growth habits, light/water/soil tolerances, hardiness zones, propagation methods.

Why authoritative: NC State Extension is a land-grant institution providing peer-reviewed horticultural guidance. The Plant Toolbox is maintained by Extension faculty and updated regularly against current botanical literature.

Visit North Carolina State Extension Plant Toolbox

University of California Statewide Integrated Pest Management Program

ipm.ucanr.edu

Used for: All pest identification, biology, life cycle, and treatment guidance — spider mites, mealybugs, scale, thrips, aphids, fungus gnats.

Why authoritative: UC IPM is the federally-recognized authority on integrated pest management in the US. Their Pest Notes series is peer-reviewed and updated regularly by UC Cooperative Extension entomologists.

Visit University of California Statewide Integrated Pest Management Program

Penn State Extension

extension.psu.edu

Used for: Fungus gnat biology and treatment, houseplant disease diagnosis, propagation techniques.

Why authoritative: Penn State College of Agricultural Sciences faculty author and review every Extension publication. Specialized strength in indoor and greenhouse horticulture.

Visit Penn State Extension

Kew Plants of the World Online (POWO)

powo.science.kew.org

Used for: Authoritative botanical names, native range, taxonomic synonyms, family classification.

Why authoritative: Royal Botanic Gardens, Kew is the global authority on plant taxonomy. POWO consolidates the International Plant Names Index and the World Checklist of Selected Plant Families.

Visit Kew Plants of the World Online (POWO)

Missouri Botanical Garden Plant Finder

missouribotanicalgarden.org

Used for: Cross-checking species-level care information, problem identification, secondary citation for toxicity.

Why authoritative: MBG is one of the oldest botanical research institutions in the US. The Plant Finder database is maintained by staff horticulturists and updated against current literature.

Visit Missouri Botanical Garden Plant Finder

NIH National Library of Medicine — MedlinePlus

medlineplus.gov

Used for: Human toxicology references (calcium oxalate, saponins, glycosides) and emergency care information.

Why authoritative: MedlinePlus is the US National Library of Medicine’s consumer health information service, peer-reviewed by NIH medical staff.

Visit NIH National Library of Medicine — MedlinePlus

University of Illinois Extension

extension.illinois.edu

Used for: Companion-pet toxicology cross-references and indoor plant care guidance.

Why authoritative: University of Illinois College of Veterinary Medicine maintains a respected toxic-plant reference used as a secondary citation when ASPCA does not have a standalone entry for a species.

Visit University of Illinois Extension

University of Florida IFAS Extension

ask.ifas.ufl.edu

Used for: Tropical and subtropical species care (anthurium, philodendron, alocasia, calathea).

Why authoritative: UF IFAS Extension specializes in tropical horticulture; many common houseplants originate from climates similar to Florida’s. Their guidance is the most relevant for subtropical species.

Visit University of Florida IFAS Extension

What we don’t cite

  • Other houseplant blogs. Useful for inspiration, never used as a factual source.
  • Reddit threads or Instagram posts. Useful for spotting real-world questions, never cited as fact.
  • Manufacturer marketing copy. Product specs from Amazon listings are not treated as horticultural fact.
  • AI chatbot answers. The guides are drafted with AI tools, but AI output is never cited as a source. Every factual claim cites a primary source.