Frost Dates for Boise, ID 83712

Last spring frost May 5 · First fall frost October 6 · 154 frost-free days · USDA Zone 7a

ZIP 83712 has about 9,070 people, one of 11 ZIP codes in Boise.

Moderate season: 154 frost-free days. Spring frost risk spans April 17–May 22 (35 days). Fall frost risk spans September 21–October 22 (31 days).

Frost probability for 83712

Frost10%50%90%
Spring (last frost)May 22May 5April 17
Fall (first frost)September 21October 6October 22

Dates come from NOAA 1971–2000 freeze probabilities at BOISE LUCKY PEAK DAM (11.4 km away); the 50% date is the median year.

Which crops fit a 154-day season in Boise

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

CropStart indoorsPlant out / sowDays you haveVerdictLast sow date
TomatoMar 31May 19–May 26112fits: 80 days to maturity, 112 available after May 19.Jun 6
PepperMar 24May 19–May 26112fits: 75 days to maturity, 112 available after May 19.Jun 11
LettuceMar 10Apr 7–Apr 14189two-plantings: Plant Apr 7 and again by Aug 15; both mature before Oct 13.Aug 15
Carrots—Apr 14–Apr 21196fits: 70 days to maturity, 196 available after Apr 14.Aug 4
CucumberApr 14May 19–May 26126fits: 60 days to maturity, 126 available after May 19.Jul 10
Beans—May 12–May 26140two-plantings: Plant May 12 and again by Jul 17; both mature before Sep 29.Jul 17
Peas—Mar 10–May 19217fits: 65 days to maturity, 217 available after Mar 10.Jul 26
ZucchiniApr 21May 19–May 26126two-plantings: Plant May 19 and again by Jul 15; both mature before Sep 22.Jul 15
OnionFeb 10Apr 7–Apr 21189fits: 100 days to maturity, 189 available after Apr 7.—
Spinach—Mar 10–Apr 28231two-plantings: Plant Mar 10 and again by Sep 3; both mature before Oct 27.Sep 3
KaleFeb 24Apr 7–Apr 21203two-plantings: Plant Apr 7 and again by Aug 19; both mature before Oct 27.Aug 19
BroccoliMar 10Apr 7–Apr 21189fits: 80 days to maturity, 189 available after Apr 7.Jul 11
CabbageMar 10Apr 7–Apr 21203fits: 70 days to maturity, 203 available after Apr 7.Aug 4
Radish—Mar 10–Jun 2217two-plantings: Plant Mar 10 and again by Sep 4; both mature before Oct 13.Sep 4
Beets—Mar 10–Jun 2217two-plantings: Plant Mar 10 and again by Aug 5; both mature before Oct 13.Aug 5
Potatoes—Apr 21–Apr 28175fits: 90 days to maturity, 175 available after Apr 21.—
Garlic—Oct 6259overwinter: Plant Oct 6 to Oct 27; harvest the following summer.Oct 27
Strawberry—Mar 31–May 26210perennial: A perennial: plant Mar 31; it fruits from the following year and keeps producing for several years.—
CornApr 7May 12–May 19126fits: 75 days to maturity, 126 available after May 12.Jun 18
PumpkinApr 21May 19–May 19119fits: 100 days to maturity, 119 available after May 19.May 24
CauliflowerMar 24Apr 28–May 12168fits: 75 days to maturity, 168 available after Apr 28.Jul 16
Swiss ChardMar 10Apr 21–Apr 21175two-plantings: Plant Apr 21 and again by Aug 5; both mature before Oct 13.Aug 5
Arugula—Mar 10–Jun 2231two-plantings: Plant Mar 10 and again by Sep 3; both mature before Oct 27.Sep 3
Brussel SproutsMar 10Apr 7–Apr 21203fits: 100 days to maturity, 203 available after Apr 7.Jul 5
Butternut SquashApr 21May 19–May 26119fits: 100 days to maturity, 119 available after May 19.May 24
EggplantMar 17May 19–May 26112fits: 70 days to maturity, 112 available after May 19.Jun 16
OkraApr 7May 12–May 19133two-plantings: Plant May 12 and again by Jul 15; both mature before Sep 22.Jul 15
BasilMar 31May 26–May 26119fits: 60 days to maturity, 119 available after May 26.Jul 10
Cilantro—Apr 7–Apr 28189two-plantings: Plant Apr 7 and again by Aug 10; both mature before Oct 13.Aug 10
ParsleyFeb 24May 12–May 19154fits: 70 days to maturity, 154 available after May 12.Jul 21
CeleryFeb 24May 12–May 26154fits: 120 days to maturity, 154 available after May 12.Jun 1
ScallionsFeb 24Apr 7–Apr 21203two-plantings: Plant Apr 7 and again by Aug 14; both mature before Oct 27.Aug 14
Turnip—Apr 7–Apr 21203two-plantings: Plant Apr 7 and again by Aug 24; both mature before Oct 27.Aug 24
Kohlrabi—Mar 24–Apr 7217two-plantings: Plant Mar 24 and again by Aug 19; both mature before Oct 27.Aug 19
Bok ChoyApr 7Apr 28–May 5168two-plantings: Plant Apr 28 and again by Aug 15; both mature before Oct 13.Aug 15
CollardsFeb 24Apr 7–Apr 21203two-plantings: Plant Apr 7 and again by Aug 14; both mature before Oct 27.Aug 14
CantaloupeApr 21May 19–May 26112fits: 85 days to maturity, 112 available after May 19.Jun 1
ChivesFeb 10May 12–May 19168fits: 90 days to maturity, 168 available after May 12.—
Dill—Mar 10–Jun 2217two-plantings: Plant Mar 10 and again by Aug 5; both mature before Oct 13.Aug 5
OreganoFeb 24May 12–May 19168fits: 80 days to maturity, 168 available after May 12.—
RosemaryFeb 10May 12–May 19154fits: 80 days to maturity, 154 available after May 12.—
SageMar 10May 12–May 19168fits: 75 days to maturity, 168 available after May 12.—
ThymeFeb 24May 12–May 19168fits: 90 days to maturity, 168 available after May 12.—
CalendulaMar 24Apr 21–May 5175two-plantings: Plant Apr 21 and again by Aug 10; both mature before Oct 13.Aug 10
CosmosApr 7May 5–May 19140two-plantings: Plant May 5 and again by Jul 10; both mature before Sep 22.Jul 10
LavenderFeb 10May 5–May 19175fits: 90 days to maturity, 175 available after May 5.—
MarigoldsMar 24May 5–May 12140two-plantings: Plant May 5 and again by Jul 20; both mature before Sep 22.Jul 20
MelonsApr 21May 19–May 26112fits: 85 days to maturity, 112 available after May 19.Jun 1
Mint—May 5–May 19175fits: 90 days to maturity, 175 available after May 5.—
NasturtiumsApr 7May 5–May 12140two-plantings: Plant May 5 and again by Jul 15; both mature before Sep 22.Jul 15
Pole Beans—May 12–May 26133fits: 65 days to maturity, 133 available after May 12.Jul 5
Spaghetti SquashApr 21May 19–May 26119fits: 90 days to maturity, 119 available after May 19.Jun 3
Sunflowers—May 5–May 19140fits: 70 days to maturity, 140 available after May 5.Jun 30
TomatillosMar 10May 12–May 19119fits: 75 days to maturity, 119 available after May 12.Jun 11
WatermelonApr 21May 12–May 19119fits: 80 days to maturity, 119 available after May 12.Jun 6
Yellow SquashApr 21May 19–May 26126two-plantings: Plant May 19 and again by Jul 15; both mature before Sep 22.Jul 15
ZinniasApr 7May 5–May 19140two-plantings: Plant May 5 and again by Jul 10; both mature before Sep 22.Jul 10

Month by month in Boise

MonthWhat to do
JanuaryPlan your garden layout and order seeds. Research varieties suited to your frost dates.
FebruaryStart indoors: Chives (Feb 10), Lavender (Feb 10), Onion (Feb 10), Rosemary (Feb 10), Celery (Feb 24), Collards (Feb 24), +5 more.
MarchStart indoors: Broccoli (Mar 10), Brussel Sprouts (Mar 10), Cabbage (Mar 10), Lettuce (Mar 10), Sage (Mar 10), Swiss Chard (Mar 10), +8 more. Direct sow from: Arugula (Mar 10), Beets (Mar 10), Dill (Mar 10), Peas (Mar 10), Radish (Mar 10), Spinach (Mar 10), +1 more. Plant: Strawberry (Mar 31).
AprilStart indoors: Bok Choy (Apr 7), Corn (Apr 7), Cosmos (Apr 7), Nasturtiums (Apr 7), Okra (Apr 7), Zinnias (Apr 7), +9 more. Direct sow from: Cilantro (Apr 7), Turnip (Apr 7), Carrots (Apr 14), Potatoes (Apr 21). Transplant from: Broccoli (Apr 7), Brussel Sprouts (Apr 7), Cabbage (Apr 7), Collards (Apr 7), Kale (Apr 7), Lettuce (Apr 7), +6 more.
MayDirect sow from: Sunflowers (May 5), Beans (May 12), Pole Beans (May 12). Transplant from: Cosmos (May 5), Lavender (May 5), Marigolds (May 5), Mint (May 5), Nasturtiums (May 5), Zinnias (May 5), +23 more. Last frost around May 5. Last sowing dates: Butternut Squash (May 24), Pumpkin (May 24).
JuneLast sowing dates: Cantaloupe (Jun 1), Celery (Jun 1), Melons (Jun 1), Spaghetti Squash (Jun 3), Tomato (Jun 6), Watermelon (Jun 6), +5 more.
JulyLast sowing dates: Brussel Sprouts (Jul 5), Pole Beans (Jul 5), Basil (Jul 10), Cosmos (Jul 10), Cucumber (Jul 10), Zinnias (Jul 10), +10 more.
AugustLast sowing dates: Cabbage (Aug 4), Carrots (Aug 4), Beets (Aug 5), Dill (Aug 5), Swiss Chard (Aug 5), Calendula (Aug 10), +8 more.
SeptemberLast sowing dates: Arugula (Sep 3), Spinach (Sep 3), Radish (Sep 4).
OctoberDirect sow from: Garlic (Oct 6). First frost around October 6. Last sowing dates: Garlic (Oct 27).
NovemberHarvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year.
DecemberClean up spent plants. Add compost to beds. Rest, review, and plan next year's garden.

Frequently Asked Questions

What is the last frost date for Boise, ID (ZIP 83712)?

The median last spring frost date for Boise, ID (ZIP code 83712) is around May 5. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area. One year in ten frost ends before April 17; one in ten it runs past May 22.

What is the first fall frost date in Boise, ID?

The median first fall frost date for Boise, ID is around October 6. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around September 21 in the earliest one-in-ten years, so cover tomatoes and peppers from then.

How long is the growing season in Boise, ID?

The frost-free growing season in Boise is about 154 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Boise (154 frost-free days, a moderate season), 32 of 56 planner crops fit outright, 23 get two plantings, 1 crop is perennial.

What USDA hardiness zone is Boise, ID?

Boise, ID is in USDA hardiness zone 7a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.

When should I start tomatoes indoors in Boise, ID?

Start tomatoes indoors Mar 31 and plant out May 19 in Boise. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.

How many plantings of lettuce fit in Boise?

Two: plant Apr 7 and again by Aug 15; both mature before Oct 13.

When do I plant garlic in Boise?

Oct 6 to Oct 27; it overwinters and is ready the following summer.

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