When to Plant Parsley in Idaho
More than a garnish. Parsley is a biennial that produces abundantly its first year and is one of the most nutritious herbs.
The Short Answer
Idaho Frost Dates
Your planting dates depend on which part of Idaho you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Northern Idaho | 5a, 5b, 6a | May 5 - May 25 | Sep 15 - Oct 5 |
| Boise Area | 6b, 7a | Apr 20 - May 5 | Oct 5 - Oct 20 |
| Eastern Idaho | 3b, 4a, 4b, 5a | May 20 - Jun 10 | Sep 1 - Sep 20 |
Parsley Planting Schedule for Idaho
Northern Idaho (Zones 5a, 5b, 6a)
Average last frost: May 5 - May 25 · Average first frost: Sep 15 - Oct 5
Boise Area (Zones 6b, 7a)
Average last frost: Apr 20 - May 5 · Average first frost: Oct 5 - Oct 20
Eastern Idaho (Zones 3b, 4a, 4b, 5a)
Average last frost: May 20 - Jun 10 · Average first frost: Sep 1 - Sep 20
Growing Parsley in Idaho
Parsley in Idaho's Climate
Parsley is one of your most reliable herbs — the biennial handles frost, grows through your moderate summers, and keeps producing from May through November. Start seeds indoors in February (parsley germinates notoriously slowly — 14-28 days). The plant is biennial: lush leaves year one, flowers and seeds year two.
Soil Considerations for Idaho
Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many areas.
Idaho Climate & Growing Season
Arid climate. Low humidity. Hot days and cool nights. Irrigation essential. Short season at higher elevations.
Growing season length varies across Idaho: Northern Idaho (5a, 5b, 6a) has a last frost around May 5 - May 25, while Eastern Idaho (3b, 4a, 4b, 5a) sees frost end around May 20 - Jun 10. This difference matters for parsley — adjust your planting dates to match your specific region.
Growing Tips
Parsley seeds are notoriously slow to germinate — soak overnight before planting. It's a biennial: lush leaves year one, seeds year two.
Companion Planting
Plant parsley alongside these companions for better growth:
The Bottom Line
Last reviewed: March 29, 2026