Plant spacing calculator

Triangular or offset spacing staggers every second row so each plant sits in the gap between two plants in the row before it, forming equilateral triangles instead of squares. Row spacing becomes 0.866 times the plant spacing, which raises density by about 15% across a large area. In a small raised bed the real gain is smaller — around 5% in a 4x8 foot bed at 6-inch spacing — because each offset row loses a plant at the edge. It suits beds you tend from the edges, and is a poor choice for anything you need to walk between.

Seed packets normally give two figures: plant spacing within the row and a wider row spacing. The wider figure exists so a person or a tractor can walk between rows, not because the plant needs it. In a raised bed you tend from the edges, so you can use the in-row spacing in both directions — which is the reason intensive beds fit so much more than a row garden of the same area.

Yes. Niwa is free to download from the App Store, and the core planner — the garden grid, the plant library and the planting calendar — works without paying. Optional in-app purchases unlock additional features.

It depends on the crop's spacing requirement. A plant needing 3 inches fits 16 per square foot, 4 inches fits 9, 6 inches fits 4, and 12 inches fits 1. Large plants such as vining tomatoes or zucchini need more than one square each. Niwa works this out for you and prints the count straight onto the grid cell.

Yes. You set the bed dimensions — 4×4, 4×8, 2×8 or a custom size — and Niwa draws the square foot grid to match. You can keep several beds and several gardens in the app at once and switch between them.

Niwa uses your location to find your average last spring frost and first autumn frost, then works backwards from those dates for every crop in your bed. Each plant gets its own sow-indoors, transplant and harvest window on a month-by-month timeline, so the dates are yours rather than a generic zone table.

Yes. As you place plants on the grid, Niwa puts a green dot between neighbouring squares that benefit each other and a red dot between squares that are better kept apart, so you see the conflict while you are still planning.

Multiply length × width × depth in feet to get cubic feet, then divide by 27 for cubic yards. A 4×8 bed at 12 inches deep needs 32 cubic feet, roughly 1.2 cubic yards or sixteen 2-cubic-foot bags.

The whole plant library and all your layouts are stored on the device, so the app works with no signal — useful on an allotment. There is no account to create and your garden data is never uploaded to a server.

Niwa works worldwide. It recognises USDA hardiness zones in the United States and derives frost dates from your location elsewhere, including the UK, Canada, Australia and Europe.

Three things: it is a native iPhone app rather than a desktop planner viewed in a mobile browser, it shows companion-planting conflicts on the grid as you place plants instead of in a separate chart, and it works fully offline with no account.

Not yet. Niwa is a native iPhone app and needs iOS 18.0 or later. An Android version is not currently available.