When to Plant Zinnias in Hawaii
The cut-and-come-again champion. The more you cut zinnias, the more they bloom. A cottage garden essential.
The Short Answer
Hawaii Frost Dates
Your planting dates depend on which part of Hawaii you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Coastal Hawaii | 11a, 11b, 12a, 12b, 13a | None | None |
| Upcountry/Mountain | 10a, 10b, 11a | Rare | Rare |
Zinnias Planting Schedule for Hawaii
Coastal Hawaii (Zones 11a, 11b, 12a, 12b, 13a)
Average last frost: None · Average first frost: None
Upcountry/Mountain (Zones 10a, 10b, 11a)
Average last frost: Rare · Average first frost: Rare
Growing Zinnias in Hawaii
Zinnias in Hawaii's Climate
Zinnias grow in subtropical zones but face more disease pressure than in drier climates. Plant during the drier months and choose disease-resistant varieties like Profusion and Zahara. In humid Florida conditions, powdery mildew and bacterial leaf spot are aggressive — the Profusion series was specifically bred to resist these.
Soil Considerations for Hawaii
Volcanic soils — extremely fertile but can be acidic. Excellent drainage on slopes. Varies dramatically by island and elevation. Make sure soil has warmed to at least 60°F before planting zinnias outside.
Hawaii Climate & Growing Season
Tropical. Year-round growing season at lower elevations. Elevation creates microclimates. Plant warm-season crops anytime. Zinnias cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Hawaii: Coastal Hawaii (11a, 11b, 12a, 12b, 13a) has a last frost around None, while Upcountry/Mountain (10a, 10b, 11a) sees frost end around Rare. This difference matters for zinnias — transplant timing shifts by several weeks across the state.
Growing Tips
Water at the base to prevent powdery mildew. Cut flowers just above a leaf node to encourage more branching and blooms.
Companion Planting
Plant zinnias alongside these companions for better growth:
The Bottom Line
Last reviewed: March 29, 2026