The reference shelf
All calculators
5 free tools, no sign-up — each one cites its extension-service sources and shows its working.
Garden
05 tools
Garden
Compost Calculator
Calculate finished compost volume and bag count, or screen a pile's browns-and-greens mix.
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Garden
Watering Schedule Calculator
Estimate net weekly irrigation in inches and gallons by crop, soil, season, growing method, bed area, and recent rainfall.
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Garden
Soil pH Calculator
Check target garden pH, compare crop ranges, and estimate lime or sulfur with a quick chart.
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Garden
Seed Spacing Calculator
Plan rows and estimate plant and seed counts with extension-cited plant spacing, row spacing, and seed depth for 20 home-garden crops.
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Garden
Fertilizer Calculator
Calculate NPK fertilizer dosage for any crop or garden area.
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