Cool-Season Vegetable

When to Plant Lettuce in Idaho

Fast-growing and forgiving. Plant in spring and fall for a nearly year-round supply of fresh salad greens.

The Short Answer

Lettuce are cold-tolerant and do well in Idaho's humid climate. You can direct sow 4 weeks before your last frost — that's as early as May 5 - May 25 in Northern Idaho. Idaho gardeners can also plant a fall crop. Volcanic ash soils in south — excellent for gardening. Rocky soils in mountains. Alkaline in many...

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

Lettuce Planting Schedule for Idaho

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

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

Start Seeds Indoors
4 wks before frost
Transplant Outside
2 wks before frost
Direct Sow
4 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

Start Seeds Indoors
4 wks before frost
Transplant Outside
2 wks before frost
Direct Sow
4 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

Start Seeds Indoors
4 wks before frost
Transplant Outside
2 wks before frost
Direct Sow
4 wks before frost
Fall Planting
8 wks before first frost

Growing Lettuce in Idaho

Lettuce in Idaho's Climate

Your cool climate is actually excellent for lettuce — the crop thrives in 55-70°F conditions that you have for months. Direct sow as soon as soil thaws in spring and continue harvesting well into summer because your moderate temperatures delay bolting far longer than in southern states. Fall lettuce is equally productive. In the coldest zones, cold frames extend harvest into December.

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 lettuce — adjust your planting dates to match your specific region.

Growing Tips

Succession plant every 2-3 weeks for continuous harvest. Shade cloth extends the season into warmer months.

Companion Planting

Plant lettuce alongside these companions for better growth:

Carrots Radishes Strawberries Chives

The Bottom Line

Lettuce 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

Lettuce Growing Guide National planting guide with all states Idaho Planting Calendar All plants for Idaho Lettuce in Alabama Alabama planting dates Lettuce in Alaska Alaska planting dates Lettuce in Arizona Arizona planting dates Lettuce 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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