When to Plant in Boise, ID

Boise's high-desert climate is excellent for gardening — Zone 7a/7b with a last frost around May 5. Hot, dry summers are perfect for tomatoes and peppers that struggle in the Pacific Northwest's maritime climate. Boise gets about 200+ sunny days per year.

Irrigation is the main challenge in Boise gardening. The city gets only 12 inches of rain per year, with essentially none from June through September. But the sunny days and warm temperatures produce exceptional summer vegetables.

What to plant now in Boise

Spring: After May 5 last frost — tomatoes, peppers, squash, beans, and cucumbers.
Early Spring (Mar–Apr): Peas, spinach, lettuce, and kale as soil warms.
Fall: Broccoli, kale, lettuce, and carrots for October harvest.
Winter: Garlic planted in fall overwinters. Planning and seed starting.

In Boise (154 frost-free days, a moderate season), 32 of 56 planner crops fit outright, 23 get two plantings, 1 crop is perennial.

Month by month in Boise

Month	What to do
January	Order seeds. Plan garden layout.
February	Start onion and leek seeds indoors.
March	Start tomato and pepper seeds. Direct sow peas and spinach when soil thaws.
April	After May 5 — transplant warm-season crops. Set up irrigation.
May	Full spring garden. No rain expected — water consistently.
June	Hot summer begins. Irrigate deeply.
July	Peak growing season. Deep water twice weekly.
August	Harvest summer crops. Plant fall broccoli and kale.
September	Fall lettuce and spinach. First frosts possible late month.
October	First frost around October 6. Harvest tender crops. Plant garlic.
November	Garden winds down.
December	Rest season.

Frost dates for Boise ZIP codes

ZIP	Last spring frost (50%)	First fall frost (50%)	Zone
83709	May 5	October 8	7a
83706	May 5	October 6	7a
83705	May 5	October 6	7a
83712	May 5	October 6	7a

FAQ

When is the last frost date in Boise, ID?

Boise's average last frost date is around May 5. The Treasure Valley's warmer microclimate makes Boise one of Idaho's earliest planting areas.

Is Boise good for tomatoes?

Excellent! Boise's hot, sunny summers produce outstanding tomatoes. Unlike Western Oregon and Washington, Boise has the heat that tomatoes need to ripen fully and abundantly.

How much do I need to water in Boise?

A lot — Boise gets almost no rain from June through September. Drip irrigation or deep watering 2–3 times per week is essential. Mulch heavily to retain moisture.

How does Plan My Garden help Boise gardeners?

Enter your Boise zip code for planting dates calibrated to the Treasure Valley's sunny, dry climate and frost dates.