A windowsill is the smallest garden most people own, and it can still give fresh herbs every week. The trick is fitting pots to the real width of the sill, not to a hopeful guess. This free planner takes your sill width, your pot width, and how many rows you can fit. It works out how many pots fit and how many plants that gives you in total.
What this tool does
This free windowsill garden planner runs entirely in your browser. Nothing you type is sent to a server, and nothing is stored online. You open the page, enter your own measurements, and the plan appears at once, with a simple drawing of the layout below the result. You can try again as often as you like, which makes it easy to test a bigger or smaller layout before you buy soil, pots, or timber. A short plan like this beats guessing, because a garden built on guesses often wastes space, water, and plants in the first season.
How to use it
Start by measuring the real space you have, not a rough guess: length, width, and height in the same units. Enter those numbers in order, then press the calculate button and read every result line, not just the total. If a line looks wrong, change one input at a time and run the tool again, so you can see exactly which input moved the result. Check the drawing too, because it shows whether the layout fits the space you measured. Save or copy the final numbers before you shop, while they are fresh.
Reading your result
The result lines break the plan into parts, so you can check each part against your space and your budget. A total alone rarely tells the full story, but a total built from visible parts does. If a result surprises you, trust the maths first and check your inputs second: most garden surprises come from a mistyped number, mixed units, or a measurement taken from the wrong side of a bed or sill. Fix the input, not the plan, and run it again.
Worked example
Try a sill 120 cm wide, pots 12 cm wide, 2 rows, and 2 plants per pot. Each row fits 120 divided by 12, which is 10 pots. Two rows give 20 pots. At 2 plants per pot, that is 40 plants. That is plenty for weekly picking, if you sow a few new pots every two weeks to replace the ones you harvest hard.
Why this matters for a gardener
Small-space growing teaches steady habits. A sill garden needs little time, but it needs regular water and regular picking, or plants go leggy and bitter. Planning the pot count first stops overcrowding, which is the main reason sill herbs fail. A planned sill also makes rotation easy: sow, grow, pick, and replace, week by week, without a gap.
Gardening tips
Measure the sill inside the frame, and leave a finger gap between pots for air. Turn pots a quarter turn every few days so plants grow straight. Water in the morning, and empty saucers so roots never sit in water. Sow little and often, rather than sowing everything on one day.
Common questions
Is this tool really free? Yes. It runs in your browser, needs no account, and has no sign-up step. You can use it as often as you like, for as many garden plans as you like.
Is the result exact for my garden? No. It is a planning estimate from the numbers you enter. Sun, wind, drainage, and local frost dates also affect real results, so check those on site before you build or plant.
Who is it made for? Home gardeners, balcony growers, and small-space growers who want a clear plan before they spend money on soil, pots, or timber.
Spanish version: Planificador de Huerto en Alféizar Semana a Semana