Free tools
Free gardening tools
— calculators and lookups.
No signup, no email, no upsells. Quick answers when you need them — for the deeper, personalized version, the Growli app remembers your specific plants and updates with your local weather.
ZIP code to USDA hardiness zone finder
Enter your US ZIP — get your USDA zone, frost dates, growing-season length, and what to plant this week. UK postcodes route to the RHS hardiness guide.
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Watering frequency calculator
Pick your plant, pot size, light, and season — get the suggested watering interval. 25+ species supported.
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Frost date calculator
Enter a US ZIP or UK postcode — get your average last spring frost, first fall frost, growing-season length, and 6 tender crops to sow after frost.
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Pot size calculator
Pick your plant, enter your current pot size, and tell us how long since the last repot. Get a repot verdict, recommended next pot size, and soil mix.
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Light meter guide
Answer three quick questions about your window and curtains — get an estimated lux range and 6 plants that thrive at that light level, no meter needed.
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Companion plant finder
Pick any of 12 common crops — get the top 5 companion plants and 3 antagonists with the science behind each pairing, tagged strong, moderate, or traditional evidence.
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Soil pH guide
Pick a plant from 30 popular species — get the ideal pH range, how to test your soil, and the exact amendments to raise or lower pH if you are out of range.
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Plant spacing calculator
Pick a crop and enter your bed size — get plant and row spacing, total plants that fit, and the square-foot gardening alternative. 21 vegetables, herbs, and flowers.
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USDA hardiness zone & planting calendar
Pick your USDA zone and crop — see sowing, transplant, and harvest dates calibrated to your zone's frost averages.
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Plant problem diagnoser
Pick your plant species and the symptom — see the most likely causes ranked and the recovery protocol.
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