When to Plant Tulip Bulbs: Soil Temperature and Depth

Plant tulip bulbs in fall, before the first frost, once the soil at planting depth stays below 60°F (16°C). That is the rule across our sources: Penn State says spring-blooming bulbs are planted in the fall before the first frost, and Clemson says tulips and most other bulbs should wait for the cool soil, with daffodils the exception at October or November. The only region with specific dates is South Carolina, covered below. This page belongs to our tulip growing guide.

The two rules that set the date

Before the first frost (Penn State).

Soil below 60°F (16°C) at planting depth (Clemson). Clemson says to plant daffodils in October or November but to wait for other spring-flowering bulbs, tulips included, until the soil temperature at planting depth stays below 60°F. It is a temperature rule, not a date, which is why it works in any region. A soil thermometer at planting depth gives you the answer.

What our sources say, region by region

These are not national dates. Do not copy South Carolina’s calendar into a colder state. Our sources do not give dates for the Midwest, the West or the North, and we will not invent them.

Why chilling matters

Tulips need a long cold period. Penn State and UW-Madison both say 15 to 17 weeks for tulips, and Penn State says the optimal chilling temperature is 40 to 45°F (4–7°C), so a refrigerator, cool cellar or garage may work. If your ground does not give you that cold, you supply it: Clemson says to refrigerate the bulbs from purchase to planting in Central and Coastal South Carolina. For forced bulbs in pots, Clemson gives 12 to 16 weeks, so there is a range of figures. Our guide to tulips in pots covers the forcing numbers.

How deep to plant: the three answers

The multiples scale with bulb size, and Clemson’s range does not. For a bulb about 2 inches (5 cm) tall, the multiples give 5 to 6 inches (12–15 cm), which is our arithmetic and sits just under Clemson’s range; our sources give no bulb size. If you are unsure which to follow, use the multiple, which scales with your bulb.

Planting day

1. Check the soil temperature. Put a thermometer at planting depth. Clemson says it should stay below 60°F (16°C) before you plant tulips.
2. Choose a sunny, well-drained spot. NC State says full sun (6 or more hours) and well-drained soil. Clemson says good drainage is essential and pH 6 to 7 suits most bulbs.
3. Plant at depth. Use three times the bulb depth (NC State), 2.5 to 3 times the bulb height (Penn State) or 6 to 8 inches (Clemson), with the bulbs 4 to 6 inches apart (Clemson).
4. Protect against animals. NC State says mice and voles eat tulip bulbs and squirrels may dig up newly planted bulbs. Our sources do not name a deterrent.
5. Mark the spot and wait. Normal rainfall is usually enough (Clemson). Flowers arrive in middle to late spring (NC State).

What if you are late?

Our sources do not describe what happens to bulbs planted late or kept over winter, so we cannot promise results. What they do say is that coastal South Carolina plants as late as late December to early January with refrigerated bulbs, which tells you that a later planting date is workable where the winter is mild. In cold regions the first-frost rule is what Penn State gives. Keep unplanted bulbs cool, as Clemson does by refrigerating them, rather than in a warm room. Clemson’s refrigeration advice is for Central and Coastal South Carolina, so treat it as an example rather than a general rule.

After planting

Penn State says bulbs planted before the first frost bloom in early to late spring or early summer, and NC State says tulips bloom in middle to late spring. Once they flower, remove the spent flower stems and leave the foliage until it yellows (NC State), for at least six weeks (Clemson). Our guide to why tulips do not come back explains what happens the following year.

What our sources do not tell you

We found no month dates for northern or western regions, no weeks-before-frost figure, no advice on spring planting and no fall watering amount. The 60°F soil rule is Clemson’s alone.

For the whole fall job list, including what is not a fall bulb, see our fall bulb planting guide.