Free tools
Garden tools that show their working
Five calculators for the everyday garden maths: how much soil, mulch or compost to buy, how many plants fit in a bed, when to sow in sequence, how much produce a household eats, and how to keep flowers coming. Every one works without an account and uses metric units.
Each tool lists its units, assumptions and rounding, and marks any figure that is not backed by reviewed data as “not yet verified” instead of guessing.
Bulk soil, mulch and compost volume
Work out how many cubic metres or bags you need to cover a bed.
Turn an area and a spread depth into a volume in cubic metres and litres, then see the bulk delivery and bag counts rounded up to what a supplier would actually sell.
Open this tool →Plant spacing and plant count
Count seedlings for a bed on a square or staggered grid.
Given a bed size and the mature spacing you want between plants, count the rows and plants per row and check the closest two plants really are the spacing you asked for.
Open this tool →Succession sowing schedule
List planting dates at your interval for the crops we have reviewed.
Enter a crop, a date range and how often you sow, and get every planting date in between. Crops without a reviewed sowing rule stay “not yet verified” — no dates are guessed.
Open this tool →Household produce estimate
See how many kilograms of a vegetable your household eats.
Turn household size, servings and a harvest window into a kilogram total. A plant count range appears only when a reviewed yield-per-plant range exists for the crop.
Open this tool →Continuous flowering sequence
Plan flowers across the year and see which months are still gaps.
Choose the months you want flowers for and list your plants. Only plants whose flowering months have been checked against a source count, and any uncovered month stays listed as a gap.
Open this tool →
How these tools work
The full formulas, boundaries and rounding rules are documented in docs/architecture/tool-methods.md in the project repository.
- Bulk soil, mulch and compost volume — Volume = area × depth ÷ 1000, so 2 m² at 25 mm is 0.05 m³ (50 L). Bulk orders round up to the nearest 0.25 m³; bags round up to whole bags.
- Plant spacing and plant count — The usable area is the bed minus twice the edge margin. Rows and columns are the grid points inside that area at the chosen step; offset rows step by spacing × √3 ÷ 2 so diagonal neighbours stay one spacing apart.
- Succession sowing schedule — Dates are stepped from the start date by the interval until the end date, then each date is checked against the reviewed sowing window and blackout months for that exact crop slug.
- Household produce estimate — Need in kg = people × servings per person per week × weeks × grams per serving ÷ 1000. Plant counts divide that need by the reviewed yield range and round up to whole plants.
- Continuous flowering sequence — Coverage is the union of the flowering months of source-cleared entries that a reviewed rule corroborates. Target months with no verified plant stay in the gap list.