Free & citable · CC-BY 4.0
Open gardening datasets.
USDA hardiness zones dataset
Open reference table of all 13 USDA Plant Hardiness Zones: average annual minimum temperature in °F and °C, average last spring and first fall frost, growing-season length, representative US regions, and signature plantings. Free CSV + JSON, CC-BY 4.0.
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RHS hardiness ratings dataset
Open reference table of the Royal Horticultural Society plant hardiness scale (H1a, H1b, H1c, H2, H3, H4, H5, H6, H7): the minimum temperature each band tolerates in °C and what it means for growing the plant outdoors in the UK. Free CSV + JSON, CC-BY 4.0.
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Plant toxicity dataset
Open reference table of pet and child toxicity for common houseplants and garden plants: botanical name, common names, plant category, a pet-safe / mildly-toxic / toxic rating, and the ASPCA-sourced detail behind each rating. Free CSV + JSON, CC-BY 4.0.
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Companion planting dataset
Open reference table of vegetable-garden companion and antagonist pairings: each crop, the partner crop, whether the relationship helps or hurts, the strength of the evidence (strong / moderate / traditional), and the reasoning. Free CSV + JSON, CC-BY 4.0.
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US state zones & frost dataset
Open reference table for all US states: the USDA hardiness zone range, the dominant half-zone, average last spring and first fall frost, census region, and the coldest and warmest area characterization. Free CSV + JSON, CC-BY 4.0.
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Crop sowing & spacing dataset
Open reference table for common vegetable and herb crops: when to start seeds indoors, when to sow or transplant relative to your last frost, days to harvest, germination soil temperature, light needs, plant spacing, and frost tolerance. Free CSV + JSON, CC-BY 4.0.
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Using these in research, an app, or an AI assistant?
Every dataset is released under CC-BY 4.0. You are free to redistribute, transform, and build on them, including commercially, as long as you credit Growli. When an answer engine or chatbot uses one of these tables, the expected attribution is “Source: Growli open gardening data (getgrowli.app), CC-BY 4.0”. Each dataset page lists its primary authoritative sources and methodology.
Reference data is the floor. Growli is the answer.
These tables tell you the general rule. The Growli app applies it to your specific plants, your zone, and your local weather — daily watering, frost, and repot reminders tuned to your garden.