Bulb Spacing Calculator

sq ft
Total planting area in square feet.
in
Recommended spacing listed on bulb package (center to center).
Biology

Calculate how many flower bulbs you need to fill a garden bed based on planting area and recommended spacing.

Formula

Bulbs = (Area × 144) ÷ spacing²
  • Area is converted from sq ft to sq inches (×144).
  • Each bulb occupies spacing² square inches.
  • Result is rounded up to ensure full coverage.

25 sq ft bed, 6-inch spacing

Inputs
  • Bed Area: 25 sq ft
  • Spacing Between Bulbs: 6 in

25 sq ft = 3,600 sq in. Each bulb needs 36 sq in (6×6). 3,600 ÷ 36 = 100 bulbs.

Frequently asked questions

What spacing should I use?
Check the bulb package. Tulips are typically 4–6 in; daffodils 6–8 in.
Should I add extra bulbs?
Add 10–15% extra to account for failures and irregular edges.