Growli Research
Original gardening data studies
Open, source-grounded research from the Growli editorial team. Free to quote, embed and chart with attribution.
Data study · 5 July 2026
The Overfeeding Report 2026
The median houseplant needs feeding just once a month, in the growing season only — and only 2% are heavy feeders. A data study on why overfeeding, not underfeeding, harms houseplants.
Read the study →Data study · 5 July 2026
The Humidity Myth 2026
Only 1 in 6 of 8,249 catalogued plant species genuinely needs high humidity (60%+). Most popular houseplants are fine in average home air — and misting doesn't sustain humidity anyway. A data study on which plants actually need it.
Read the study →Data study · 5 July 2026
The Wrong-Soil Report 2026
77% of 10,153 catalogued plant species need free-draining soil and 35% need a specialist mix — not standard bagged compost. The wrong soil rots roots exactly like overwatering. A data study on what houseplants really need to grow in.
Read the study →Data study · 5 July 2026
The Overwatering Report 2026
67% of 8,357 catalogued plant species need watering just once a week or less — the median houseplant wants water every 7 days, and only 8% need it more than twice a week. A data study on why overwatering kills more houseplants than neglect.
Read the study →Data study · 29 June 2026
The Beginner-Proof Houseplant Barely Exists
Only 0.3% of 8,452 catalogued houseplants — just 29 species — are simultaneously low-light-tolerant, drought-tolerant and pet-safe. The near-zero overlap is a real botanical trade-off.
Read the study →Data study · 29 June 2026
Half Your Houseplants Could Survive a UK Winter
49.3% of 8,452 catalogued houseplants are hardy enough (USDA zone 8 / RHS H4+) to overwinter outdoors across much of the UK. An RHS- and USDA-grounded data study.
Read the study →Data study · 26 June 2026
The Pet-Safe Low-Light Sweet Spot 2026
Only 3.7% of 5,561 catalogued houseplants are both pet-safe and low-light-tolerant — the narrow sweet spot for renters with cats in dim flats. An ASPCA- and Extension-grounded data study.
Read the study →Data study · 26 June 2026
The Low-Light Houseplant Myth 2026
Only 2.4% of 5,561 catalogued houseplant species truly tolerate low light — 88.6% need bright indirect or direct light. An Extension-grounded data study by Growli.
Read the study →Data study · 26 June 2026
The Frost-Tender Houseplant Report 2026
More than a third of catalogued houseplant species (36.8% — 2,044 of 5,472) are frost-tender, rated hardy only to USDA zone 10 or warmer and unable to survive a hard outdoor freeze. Original data study by Growli.
Read the study →Data study · 24 June 2026
State of Houseplant Toxicity 2026
63.8% of 5,561 catalogued houseplant species are harmful to cats or dogs — and 12 of the 15 most popular houseplants are toxic. An ASPCA-grounded data study.
Read the study →