Root Vegetable

When to Plant Turnips in Idaho

A fast-growing, cold-hardy root crop that's underappreciated. Both the root and the greens are delicious.

The Short Answer

In Idaho, soil conditions are an important factor for turnips. Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many areas. Direct sow 3 weeks before your last frost date. Turnips can also be planted in fall, 8 weeks before your first frost.

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

Turnips Planting Schedule for Idaho

Northern Idaho (Zones 5a, 5b, 6a)

Average last frost: May 5 - May 25 · Average first frost: Sep 15 - Oct 5

Direct Sow
3 wks before frost
Fall Planting
8 wks before first frost

Boise Area (Zones 6b, 7a)

Average last frost: Apr 20 - May 5 · Average first frost: Oct 5 - Oct 20

Direct Sow
3 wks before frost
Fall Planting
8 wks before first frost

Eastern Idaho (Zones 3b, 4a, 4b, 5a)

Average last frost: May 20 - Jun 10 · Average first frost: Sep 1 - Sep 20

Direct Sow
3 wks before frost
Fall Planting
8 wks before first frost

Growing Turnips in Idaho

Turnips in Idaho's Climate

Turnips are a fast, cold-hardy root crop perfect for extending your short season. Direct sow 3 weeks before last frost and again in late August for frost-sweetened fall harvest. Both roots and greens are edible, doubling the crop's value. Hakurei Japanese salad turnips are especially quick — ready in 30-35 days.

Soil Considerations for Idaho

Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many areas. Loose, well-drained soil is especially important for turnips since the edible portion grows underground. If your soil is heavy clay, consider raised beds.

Idaho Climate & Growing Season

Arid climate. Low humidity. Hot days and cool nights. Irrigation essential. Short season at higher elevations. Turnips can handle frost well, which is an advantage in Idaho's climate. You can push planting dates earlier in spring and extend into fall.

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 turnips — but turnips handle frost well, so the timing difference is less critical.

Growing Tips

Great for spring and fall planting. Harvest small for tender roots. Fall-planted turnips taste sweeter after a frost.

Companion Planting

Plant turnips alongside these companions for better growth:

Peas Onions

The Bottom Line

Turnips can be grown successfully across Idaho, but your exact planting dates depend on which region you're in. Northern Idaho gardeners should plan around a May 5 - May 25 last frost, while those in Eastern Idaho can typically plant later. For exact dates based on your zip code, use our free planting date finder.

Related Guides

Turnips Growing Guide National planting guide with all states Idaho Planting Calendar All plants for Idaho Turnips in Alabama Alabama planting dates Turnips in Alaska Alaska planting dates Turnips in Arizona Arizona planting dates Turnips in Arkansas Arkansas planting dates
Note: All dates are based on NOAA 30-year Climate Normals and represent historical averages, not predictions for any specific year. Always check your local weather forecast before planting frost-sensitive crops. Learn about our data sources.

Last reviewed: March 29, 2026

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