How this calculator works
Centres start at the specified border and continue at fixed spacing while remaining inside the usable rectangle. A triangular layout shifts alternate rows by half the within-row distance and sets row spacing to sqrt(3)/2 of that distance. Presets select a value within University of Georgia bulb-spacing guidance; cultivar size and naturalizing plans can require more room. Georgia planting-season advice does not automatically apply to Canadian winters.
Formula
Usable L = L - 2b and W = W - 2b. Rectangular rows = floor(W/r) + 1; bulbs per row = floor(L/s) + 1. Triangular rows alternate an additional half-spacing horizontal offset.
Worked example
A 1 m square with no centre border and 50 cm square spacing holds 3 rows of 3 bulbs, or 9. A 25 cm border reduces this to 2 rows of 2 bulbs, or 4.
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Frequently asked questions
Why can a bulb fit on the border line?
The border is measured to the bulb centre. A zero border places centres on the bed boundary; use a positive border to keep bulbs fully inside.
Why does triangular planting fit differently?
Rows are closer by a factor of sqrt(3)/2, but shifted rows may lose one bulb at the edge.
Are these depths or spacing distances?
They are horizontal centre-to-centre distances. Planting depth is a separate decision based on bulb type and local conditions.