Biology
Count the flower bulbs needed to fill a bed at your spacing.
Your inputs
Change any value — everything updates instantly.
Length × width of the planting area.
From the bulb package: tulips ~4–6 in, crocus ~2–3 in.
Try an example
Bulbs needed
116 bulbs
This means you should buy about 116 bulbs to fill the bed.
What you are seeing
Each dot is one bulb, planted one at a time.
At 5 in spacing you fit 5.76 per square foot.
116 bulbs in total.
Bulbs per ft²
5.76
Density at your spacing.
Packs of 10
12 packs
Rounded up to whole packs.
Packs of 25
5 packs
If sold in larger bags.
Result explanation: Bulbs to buy
116 bulbs at 5 in.
Real-life comparison: Doubling spacing would need about 29.
Low, normal or high? Closer spacing gives a fuller display sooner.
Bulbs against spacing
How to read this chart: Bulbs drop fast as spacing widens. The red dot is yours.
Divides the bed area by the square each bulb occupies.
116 bulbs.
Plant at about 2–3 times the bulb's height deep.
Buy a few extra for gaps.
Turn the bed into square inches, then divide by each bulb's square.
bulbs = ⌈area × 144 ÷ spacing²⌉
Symbols
Why this formula works
Each bulb gets a square of side equal to the spacing.
Unit check
ft² × in²/ft² ÷ in² = bulbs ✓
Worked example
Common mistakes
Buy about 116 bulbs.
On the bulb package or supplier's planting guide.
Scatter bulbs and plant where they land; the count is similar.
For 'lasagne' planting, calculate each layer separately.
Spring-flowering bulbs are planted in autumn in temperate climates.
Reviewed 2026-09-25 · Next review 2027-09-25
Important limitation. Planning estimate.
Tell us if a formula, unit, explanation, or result needs attention. Your message will include this calculator’s name and page.
CO₂ Grow Room Calculator
Find how much CO₂ raises a sealed grow room from ambient to your target ppm.
Compost Calculator
Work out how much compost you need for a bed or area, in cubic yards, cubic feet, litres and bags.
Daily Light Integral Calculator
Turn grow-light PPFD and hours into the daily light integral plants receive.
Fertilizer Calculator
Turn a nutrient rate into the amount of fertilizer product to apply.
Mulch Calculator
Work out how much mulch you need for a bed or area, in cubic yards, cubic feet, litres and bags.
Pine Straw Calculator
Count pine straw bales and cost for your beds using your supplier's coverage per bale.
