Frost Dates for Boise, ID 83702
Boise has 11 ZIP codes. The Boise, ID frost page lists all of them with their dates.
Last spring frost May 5 · First fall frost October 6 · 154 frost-free days · USDA Zone 7a
ZIP 83702 has about 24,200 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 83702
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 22 | May 5 | April 17 |
| Fall (first frost) | September 21 | October 6 | October 22 |
Dates come from NOAA 1971–2000 freeze probabilities at BOISE LUCKY PEAK DAM (18.2 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.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 31 | May 19–May 26 | 112 | fits: 80 days to maturity, 112 available after May 19. | Jun 6 |
| Pepper | Mar 24 | May 19–May 26 | 112 | fits: 75 days to maturity, 112 available after May 19. | Jun 11 |
| Lettuce | Mar 10 | Apr 7–Apr 14 | 189 | two-plantings: Plant Apr 7 and again by Aug 15; both mature before Oct 13. | Aug 15 |
| Carrots | — | Apr 14–Apr 21 | 196 | fits: 70 days to maturity, 196 available after Apr 14. | Aug 4 |
| Cucumber | Apr 14 | May 19–May 26 | 126 | fits: 60 days to maturity, 126 available after May 19. | Jul 10 |
| Beans | — | May 12–May 26 | 140 | two-plantings: Plant May 12 and again by Jul 17; both mature before Sep 29. | Jul 17 |
| Peas | — | Mar 10–May 19 | 217 | fits: 65 days to maturity, 217 available after Mar 10. | Jul 26 |
| Zucchini | Apr 21 | May 19–May 26 | 126 | two-plantings: Plant May 19 and again by Jul 15; both mature before Sep 22. | Jul 15 |
| Onion | Feb 10 | Apr 7–Apr 21 | 189 | fits: 100 days to maturity, 189 available after Apr 7. | — |
| Spinach | — | Mar 10–Apr 28 | 231 | two-plantings: Plant Mar 10 and again by Sep 3; both mature before Oct 27. | Sep 3 |
| Kale | Feb 24 | Apr 7–Apr 21 | 203 | two-plantings: Plant Apr 7 and again by Aug 19; both mature before Oct 27. | Aug 19 |
| Broccoli | Mar 10 | Apr 7–Apr 21 | 189 | fits: 80 days to maturity, 189 available after Apr 7. | Jul 11 |
| Cabbage | Mar 10 | Apr 7–Apr 21 | 203 | fits: 70 days to maturity, 203 available after Apr 7. | Aug 4 |
| Radish | — | Mar 10–Jun 2 | 217 | two-plantings: Plant Mar 10 and again by Sep 4; both mature before Oct 13. | Sep 4 |
| Beets | — | Mar 10–Jun 2 | 217 | two-plantings: Plant Mar 10 and again by Aug 5; both mature before Oct 13. | Aug 5 |
| Potatoes | — | Apr 21–Apr 28 | 175 | fits: 90 days to maturity, 175 available after Apr 21. | — |
| Garlic | — | Oct 6 | 259 | overwinter: Plant Oct 6 to Oct 27; harvest the following summer. | Oct 27 |
| Strawberry | — | Mar 31–May 26 | 210 | perennial: A perennial: plant Mar 31; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 7 | May 12–May 19 | 126 | fits: 75 days to maturity, 126 available after May 12. | Jun 18 |
| Pumpkin | Apr 21 | May 19–May 19 | 119 | fits: 100 days to maturity, 119 available after May 19. | May 24 |
| Cauliflower | Mar 24 | Apr 28–May 12 | 168 | fits: 75 days to maturity, 168 available after Apr 28. | Jul 16 |
| Swiss Chard | Mar 10 | Apr 21–Apr 21 | 175 | two-plantings: Plant Apr 21 and again by Aug 5; both mature before Oct 13. | Aug 5 |
| Arugula | — | Mar 10–Jun 2 | 231 | two-plantings: Plant Mar 10 and again by Sep 3; both mature before Oct 27. | Sep 3 |
| Brussel Sprouts | Mar 10 | Apr 7–Apr 21 | 203 | fits: 100 days to maturity, 203 available after Apr 7. | Jul 5 |
| Butternut Squash | Apr 21 | May 19–May 26 | 119 | fits: 100 days to maturity, 119 available after May 19. | May 24 |
| Eggplant | Mar 17 | May 19–May 26 | 112 | fits: 70 days to maturity, 112 available after May 19. | Jun 16 |
| Okra | Apr 7 | May 12–May 19 | 133 | two-plantings: Plant May 12 and again by Jul 15; both mature before Sep 22. | Jul 15 |
| Basil | Mar 31 | May 26–May 26 | 119 | fits: 60 days to maturity, 119 available after May 26. | Jul 10 |
| Cilantro | — | Apr 7–Apr 28 | 189 | two-plantings: Plant Apr 7 and again by Aug 10; both mature before Oct 13. | Aug 10 |
| Parsley | Feb 24 | May 12–May 19 | 154 | fits: 70 days to maturity, 154 available after May 12. | Jul 21 |
| Celery | Feb 24 | May 12–May 26 | 154 | fits: 120 days to maturity, 154 available after May 12. | Jun 1 |
| Scallions | Feb 24 | Apr 7–Apr 21 | 203 | two-plantings: Plant Apr 7 and again by Aug 14; both mature before Oct 27. | Aug 14 |
| Turnip | — | Apr 7–Apr 21 | 203 | two-plantings: Plant Apr 7 and again by Aug 24; both mature before Oct 27. | Aug 24 |
| Kohlrabi | — | Mar 24–Apr 7 | 217 | two-plantings: Plant Mar 24 and again by Aug 19; both mature before Oct 27. | Aug 19 |
| Bok Choy | Apr 7 | Apr 28–May 5 | 168 | two-plantings: Plant Apr 28 and again by Aug 15; both mature before Oct 13. | Aug 15 |
| Collards | Feb 24 | Apr 7–Apr 21 | 203 | two-plantings: Plant Apr 7 and again by Aug 14; both mature before Oct 27. | Aug 14 |
| Cantaloupe | Apr 21 | May 19–May 26 | 112 | fits: 85 days to maturity, 112 available after May 19. | Jun 1 |
| Chives | Feb 10 | May 12–May 19 | 168 | fits: 90 days to maturity, 168 available after May 12. | — |
| Dill | — | Mar 10–Jun 2 | 217 | two-plantings: Plant Mar 10 and again by Aug 5; both mature before Oct 13. | Aug 5 |
| Oregano | Feb 24 | May 12–May 19 | 168 | fits: 80 days to maturity, 168 available after May 12. | — |
| Rosemary | Feb 10 | May 12–May 19 | 154 | fits: 80 days to maturity, 154 available after May 12. | — |
| Sage | Mar 10 | May 12–May 19 | 168 | fits: 75 days to maturity, 168 available after May 12. | — |
| Thyme | Feb 24 | May 12–May 19 | 168 | fits: 90 days to maturity, 168 available after May 12. | — |
| Calendula | Mar 24 | Apr 21–May 5 | 175 | two-plantings: Plant Apr 21 and again by Aug 10; both mature before Oct 13. | Aug 10 |
| Cosmos | Apr 7 | May 5–May 19 | 140 | two-plantings: Plant May 5 and again by Jul 10; both mature before Sep 22. | Jul 10 |
| Lavender | Feb 10 | May 5–May 19 | 175 | fits: 90 days to maturity, 175 available after May 5. | — |
| Marigolds | Mar 24 | May 5–May 12 | 140 | two-plantings: Plant May 5 and again by Jul 20; both mature before Sep 22. | Jul 20 |
| Melons | Apr 21 | May 19–May 26 | 112 | fits: 85 days to maturity, 112 available after May 19. | Jun 1 |
| Mint | — | May 5–May 19 | 175 | fits: 90 days to maturity, 175 available after May 5. | — |
| Nasturtiums | Apr 7 | May 5–May 12 | 140 | two-plantings: Plant May 5 and again by Jul 15; both mature before Sep 22. | Jul 15 |
| Pole Beans | — | May 12–May 26 | 133 | fits: 65 days to maturity, 133 available after May 12. | Jul 5 |
| Spaghetti Squash | Apr 21 | May 19–May 26 | 119 | fits: 90 days to maturity, 119 available after May 19. | Jun 3 |
| Sunflowers | — | May 5–May 19 | 140 | fits: 70 days to maturity, 140 available after May 5. | Jun 30 |
| Tomatillos | Mar 10 | May 12–May 19 | 119 | fits: 75 days to maturity, 119 available after May 12. | Jun 11 |
| Watermelon | Apr 21 | May 12–May 19 | 119 | fits: 80 days to maturity, 119 available after May 12. | Jun 6 |
| Yellow Squash | Apr 21 | May 19–May 26 | 126 | two-plantings: Plant May 19 and again by Jul 15; both mature before Sep 22. | Jul 15 |
| Zinnias | Apr 7 | May 5–May 19 | 140 | two-plantings: Plant May 5 and again by Jul 10; both mature before Sep 22. | Jul 10 |
Month by month in Boise
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 10), Lavender (Feb 10), Onion (Feb 10), Rosemary (Feb 10), Celery (Feb 24), Collards (Feb 24), +5 more. |
| March | Start 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). |
| April | Start 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. |
| May | Direct 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). |
| June | Last sowing dates: Cantaloupe (Jun 1), Celery (Jun 1), Melons (Jun 1), Spaghetti Squash (Jun 3), Tomato (Jun 6), Watermelon (Jun 6), +5 more. |
| July | Last sowing dates: Brussel Sprouts (Jul 5), Pole Beans (Jul 5), Basil (Jul 10), Cosmos (Jul 10), Cucumber (Jul 10), Zinnias (Jul 10), +10 more. |
| August | Last sowing dates: Cabbage (Aug 4), Carrots (Aug 4), Beets (Aug 5), Dill (Aug 5), Swiss Chard (Aug 5), Calendula (Aug 10), +8 more. |
| September | Last sowing dates: Arugula (Sep 3), Spinach (Sep 3), Radish (Sep 4). |
| October | Direct sow from: Garlic (Oct 6). First frost around October 6. Last sowing dates: Garlic (Oct 27). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| December | Clean 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 83702)?
The median last spring frost date for Boise, ID (ZIP code 83702) 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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