Flower Bulb Planting Calendar by USDA Zone

Bulb planting dates are usually given as months, which is useless if you garden somewhere unusual. The real signal is soil temperature: spring bulbs go in when soil falls below 13°C (55°F), summer bulbs when it rises above 12°C (54°F).

Spring-flowering bulbs (planted in autumn)

Tulips, daffodils, hyacinths, crocus, alliums, muscari.

• Zone 3: mid September – mid October
• Zone 4: late September – late October
• Zone 5: early October – early November
• Zone 6: mid October – mid November
• Zone 7: late October – late November
• Zone 8: November – early December
• Zone 9: late November – mid December (pre-chill hyacinths and tulips)
• Zone 10: pre-chill 10–12 weeks, then plant December – January

Summer-flowering bulbs (planted in spring)

Dahlias, gladioli, lilies, crocosmia.

• Zones 3–4: late May – early June, after last frost
• Zones 5–6: mid May – early June
• Zones 7–8: April – May
• Zones 9–10: March – April, or autumn for some lilies

Soil must be above 12°C. Cold soil rots dahlia tubers before they sprout — if in doubt, wait a week.

Autumn-flowering bulbs

Colchicum and autumn crocus go in during late summer — July to August — because they flower within weeks of planting.

How to check your soil temperature

Push a soil thermometer 10 cm down at 9 am for three consecutive days and average the readings. This is more reliable than any calendar, because a warm autumn can push planting back by a month.

What happens if you plant late

Bulbs planted after their window still grow, but they flower later and with shorter stems. Late-planted tulips often skip flowering entirely in their first year. It is better to plant late than not at all — but do not expect a perfect display.

What happens if you plant early

Warm soil encourages top growth before roots are established. A hard frost then damages the shoot. Wait for the soil to cool; there is no benefit to planting in September in zone 8.

Quick reference

• Spring bulbs: soil below 13°C, 12–16 weeks before last frost
• Summer bulbs: soil above 12°C, after last frost
• Planting depth: three times bulb height
• Spacing: 10–15 cm for bedding, 15–20 cm for naturalising

Browse bulbs by season in our online shop.