Flower Bed Planner
Plant count, bed area, edging length and mulch volume for a flower bed.
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Flower Bulb Spacing Calculator
How many spring bulbs to buy for a bed, by bulb type, area and pack size.
Flower Bulb Spacing Calculator
Chlorova · updated for 2026
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Density is a per-square-foot average that works for a formal mass planting; a naturalized or scattered look in the same bed uses the same total but reads looser, and drifts leave gaps that lower the effective count. Bulb size within a type shifts spacing too — a jumbo tulip wants a touch more room than the standard figure, and small crocus can sit tighter, so treat these counts as a starting shopping number.
The flower bulb spacing calculator converts a bed's area and a bulb type into the number of bulbs — and the packs to order — for a fall planting, so you buy the right quantity before the best stock sells out. Tulips, daffodils, crocus and alliums each want a different spacing, so the same bed takes wildly different counts depending on what you plant. Choose the bulb, enter the square footage and your pack size and price, and it returns bulbs, packs, cost and a planting-depth note for that type.
How to Plan a Bulb Bed
- Pick the bulb you want to plant from the drop-down list.
- Enter the square footage of the bed or lawn edge you will plant.
- Set how many bulbs come in the pack you are actually buying.
- Type the pack price to get a realistic total order cost.
- Read the total bulb count the bed needs at that spacing.
- Order a few extra — bulbs get eaten, lost or misplaced.
- Note the planting-depth advice shown for your bulb type.
- Plant in early fall before the ground freezes hard, not in late autumn panic.
How the Bulb Count Is Worked Out
Each bulb type has a natural planting density expressed as bulbs per square foot: tulips about two, daffodils one, crocus four and alliums half. Multiply that density by the bed area and round up to get the bulbs you need. Packs is that count divided by your pack size, rounded up, and cost is the pack count times the price. A thirty square-foot tulip bed at two per foot needs sixty bulbs, which is six ten-bulb packs.
Why density follows mature spacing: a bulb left at the right distance fills in and can be lifted or naturalized without crowding, while bulbs jammed past their spacing compete for water and root room, come up blind, and need dividing early. The per-foot figures here come straight from each type's recommended gap — six inches for tulips, twelve for daffodils, three for crocus, eighteen for alliums — so the count reflects how the planting actually looks a season later, not how tight it can be squeezed on day one.
Worked Example: A Twenty-Foot Tulip Border
- Your front border is twenty square feet and you want tulips.
- Tulip density is two bulbs per square foot at six-inch spacing.
- Bulbs needed: twenty × two = forty bulbs exactly.
- In ten-bulb packs that is four packs, with no awkward remainder.
- At twelve dollars a pack, the order runs forty-eight dollars.
- Order one extra pack — squirrels and a few soft bulbs are a real tax.
- Plant each bulb about six inches deep, three times its own height.
- Set them pointed-end up in firm, well-drained soil and water once after planting.
- Mark the beds with sticks so you never dig a spade into hidden bulbs later.
Spacing and Density by Bulb
Recommended in-ground spacing and the resulting bulbs per square foot for the four common types here. Use the density column to sanity-check the count, and remember bigger jumbo bulbs of the same type want a little more room than the standard figure implies.
| Bulb | Spacing | Bulbs per sq ft |
|---|---|---|
| Tulip | 6 in | 2 |
| Daffodil | 12 in | 1 |
| Crocus | 3 in | 4 |
| Allium | 18 in | 0.5 |
Key Terms
- Naturalizing
- Planting bulbs so they multiply and return on their own, spreading into a perennial colony.
- Blind
- A bulb that leafs out but fails to flower, often from crowding or cutting the foliage too early.
- Tulip depth rule
- Planting a bulb about three times its own height deep, which suits most spring bulbs.
- Drift
- A loose mass of one bulb type planted to look natural rather than in formal rows.
- Chilling
- The cold winter hours a spring bulb needs before it will break dormancy and flower.
What This Means for a Fall Bulb Order
- Order in September, not November — the best tulips, daffodils and specialty alliums sell out by late fall, and the leftover stock is whatever nobody wanted at full price.
- Plant in generous drifts of a single variety rather than mixing one of each; twelve of one tulip reads as a designer's decision, while twelve different bulbs reads as a sample bag.
- Cut the count slightly for a naturalized lawn edge and let them self-sow — daffodils and crocus will spread, so a modest first planting fills the space fuller over five years.
- Depth matters more than spacing for bloom: a bulb planted at three times its height gets the chill and root run it wants, while a shallow tulip lifts and blinds the next spring.
- Always buy about ten percent over the calculator's number — rodent loss, a few soft bulbs out of the bag, and the block you dig over later are a real, ordinary tax on any bulb bed.
Common Mistakes & Fixes
- Ordering too late in the season and getting picked-over bulbs, then blaming the soil when half of them blind.
- Planting one of every color instead of big drifts, so the bed looks messy rather than the intended mass of bloom.
- Crowding bulbs tighter than their mature spacing, which starves them into no flowers the second year.
- Betting on daffodils to eat-proof your lawn while squirrels and chipmunks dig the tulips out within a week of planting.
- Cutting the foliage as soon as bloom fades, which starves the bulb before it recharges and guarantees a weak spring next year.
When to Use This (and When Not To)
Use it in early fall to size a spring-bloom bulb order for a known bed area before the good stock sells out. It is about bulbs, not annual flowers or vegetables — for those use the flower bed planner or the plant-spacing tools, which think in plants rather than underground storage organs. For a naturalizing scheme meant to spread over years, plant on the low end of the count and let the bulbs multiply into the space themselves.
Flower Bulb Spacing Calculator: Frequently Asked Questions
How many tulip bulbs do I need for a bed?
About two bulbs per square foot at a six-inch spacing, so a twenty square-foot border takes around forty bulbs. Order a few extra to cover rodent loss and the soft bulbs you toss at planting.
How deep should I plant spring bulbs?
Roughly three times the height of the bulb, pointed end up. That works for tulips, daffodils and most spring bulbs; small crocus go shallower and big alliums deeper. Depth gives the bulb the chill and root room it needs to flower.
How many daffodils per square foot?
About one, at a twelve-inch spacing, because daffodils are larger and naturalize by spreading between the gaps over the years. Planting them at the full space lets the colony thicken on its own without lifting and dividing.
When should I buy and plant bulbs?
Buy in September while the selection is full, and plant in the fall once nights are cool but before the ground freezes hard. Bulbs need a run of cold winter weeks to bloom, so a late planting still works as long as the soil has not frozen solid.
Will squirrels eat my tulips?
Very often, yes — tulips are a favorite. Daffodils, alliums and fritillaria are usually left alone because they are toxic or fragrant, so plant those where rodents rule and protect tulips with netting or grow them in containers.
Should I cut bulb leaves after flowering?
No — leave the foliage until it yellows and falls over on its own. The leaves recharge the bulb for next spring, and cutting them early starves it, which is the most common reason a once-good bulb bed goes blind the following year.
Sources & Further Reading
- Planting and Care of Spring-Flowering Bulbs — Cornell University Gardening Program
- Bulb Spacing, Depth and Naturalizing — Royal Horticultural Society
- Fall Bulb Planting for Home Gardens — Ohio State University Extension
Chlorova Gardening Team
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Checked against extension-service publications
Formula verified against published references · Updated