When to Plant Cosmos in New York
Delicate, daisy-like blooms that dance in the breeze. Cosmos thrive in poor soil and practically grow themselves.
The Short Answer
New York Frost Dates
Your planting dates depend on which part of New York you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Adirondacks | 3b, 4a, 4b | May 20 - Jun 5 | Sep 5 - Sep 20 |
| Capital Region/Hudson Valley | 5a, 5b, 6a | May 1 - May 15 | Sep 25 - Oct 10 |
| New York City/Long Island | 7a, 7b | Apr 5 - Apr 20 | Oct 20 - Nov 10 |
| Western New York | 5b, 6a | May 1 - May 15 | Sep 25 - Oct 10 |
Cosmos Planting Schedule for New York
Adirondacks (Zones 3b, 4a, 4b)
Average last frost: May 20 - Jun 5 · Average first frost: Sep 5 - Sep 20
Capital Region/Hudson Valley (Zones 5a, 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 10
New York City/Long Island (Zones 7a, 7b)
Average last frost: Apr 5 - Apr 20 · Average first frost: Oct 20 - Nov 10
Western New York (Zones 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 10
Growing Cosmos in New York
Cosmos in New York's Climate
Cosmos are the zero-effort flower. Direct sow from mid-May. No fertilizer, no fussing, no deadheading necessary (though it helps). They grow 3-5 feet tall and self-seed prolifically. Perfect for filling unused garden edges with color and pollinator habitat.
Soil Considerations for New York
Diverse soils. Rich agricultural land in western NY and Hudson Valley. Rocky in Adirondacks. Clay in some areas. Make sure soil has warmed to at least 60°F before planting cosmos outside.
New York Climate & Growing Season
Wide climate variation. NYC has mild winters. Adirondacks have very short seasons. Lake effect modifies weather near Great Lakes. Cosmos 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 New York: Adirondacks (3b, 4a, 4b) has a last frost around May 20 - Jun 5, while Western New York (5b, 6a) sees frost end around May 1 - May 15. This difference matters for cosmos — transplant timing shifts by several weeks across the state.
Growing Tips
Don't over-fertilize — rich soil produces more leaves and fewer flowers. Let some flowers go to seed for next year's crop.
Companion Planting
Plant cosmos alongside these companions for better growth:
The Bottom Line
Last reviewed: March 29, 2026