Flower · Liliaceae
When to sow tulips
The bulb that made autumn planting a habit. Tulips need a real winter to flower properly, which is why they are magnificent in Amsterdam and a disappointment in Los Angeles, where they are treated as one-season bedding and discarded.
Days to maturity
150-200
From sowing to a first picking.
Hardy in USDA zones
3a to 8a
Winter cold sets the limit here, not the calendar.
Frost tolerance
Very hardy
How much cold the plant itself will take.
Those weeks become real dates once you name a place.
Timing, in frost-relative terms
Tulips are anchored to the first autumn frost rather than the last spring one, so the useful offset runs backwards from the end of the season instead of forwards from its start.
- Expect 150–200 days to maturity, counted from sowing.
- Hardy in USDA zones 3a–8a.
- Can also be sown in late summer for an autumn crop or to overwinter.
Getting the timing right
Plant four to six weeks before your first autumn frost, once the soil has cooled below about 15C - warm soil encourages the rot that hollows bulbs out over winter. Late planting is far less damaging than early; bulbs put in at the start of winter simply flower a little later. Depth matters more than date: 15cm, about three times the height of the bulb.
Frost tolerance
The bulb is hardy to around -25C once underground. Cold is the requirement rather than the risk: without twelve to fourteen weeks below 9C the stem stays short and the flower opens at ground level or not at all. In zone 9 and warmer, buy pre-chilled bulbs and treat them as annuals.
Classified as very-hardy, with damage expected below -25°C (-13°F)-13°F (-25°C).