Frost Dates for Rupert, ID 83350
Last spring frost May 14 · First fall frost September 24 · 133 frost-free days · USDA Zone 6a
ZIP 83350 has about 12,700 people.
Moderate season: 133 frost-free days. Spring frost risk spans April 27–June 2 (36 days). Fall frost risk spans September 10–October 7 (27 days).
Frost probability for 83350
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | June 2 | May 14 | April 27 |
| Fall (first frost) | September 10 | September 24 | October 7 |
Dates come from NOAA 1971–2000 freeze probabilities at MINIDOKA DAM (8.7 km away); the 50% date is the median year.
Which crops fit a 133-day season in Rupert
In Rupert (133 frost-free days, a moderate season), 37 of 56 planner crops fit outright, 16 get two plantings, 2 need an indoor start, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 9 | May 28–Jun 4 | 91 | fits: 80 days to maturity, 91 available after May 28. | — |
| Pepper | Apr 2 | May 28–Jun 4 | 91 | fits: 75 days to maturity, 91 available after May 28. | May 30 |
| Lettuce | Mar 19 | Apr 16–Apr 23 | 168 | two-plantings: Plant Apr 16 and again by Aug 3; both mature before Oct 1. | Aug 3 |
| Carrots | — | Apr 23–Apr 30 | 175 | fits: 70 days to maturity, 175 available after Apr 23. | Jul 23 |
| Cucumber | Apr 23 | May 28–Jun 4 | 105 | fits: 60 days to maturity, 105 available after May 28. | Jun 28 |
| Beans | — | May 21–Jun 4 | 119 | fits: 60 days to maturity, 119 available after May 21. | Jul 5 |
| Peas | — | Mar 19–May 28 | 196 | fits: 65 days to maturity, 196 available after Mar 19. | Jul 14 |
| Zucchini | Apr 30 | May 28–Jun 4 | 105 | fits: 55 days to maturity, 105 available after May 28. | Jul 3 |
| Onion | Feb 19 | Apr 16–Apr 30 | 168 | fits: 100 days to maturity, 168 available after Apr 16. | — |
| Spinach | — | Mar 19–May 7 | 210 | two-plantings: Plant Mar 19 and again by Aug 22; both mature before Oct 15. | Aug 22 |
| Kale | Mar 5 | Apr 16–Apr 30 | 182 | two-plantings: Plant Apr 16 and again by Aug 7; both mature before Oct 15. | Aug 7 |
| Broccoli | Mar 19 | Apr 16–Apr 30 | 168 | fits: 80 days to maturity, 168 available after Apr 16. | Jun 29 |
| Cabbage | Mar 19 | Apr 16–Apr 30 | 182 | fits: 70 days to maturity, 182 available after Apr 16. | Jul 23 |
| Radish | — | Mar 19–Jun 11 | 196 | two-plantings: Plant Mar 19 and again by Aug 23; both mature before Oct 1. | Aug 23 |
| Beets | — | Mar 19–Jun 11 | 196 | two-plantings: Plant Mar 19 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Potatoes | — | Apr 30–May 7 | 154 | fits: 90 days to maturity, 154 available after Apr 30. | — |
| Garlic | — | Sep 24 | 238 | overwinter: Plant Sep 24 to Oct 15; harvest the following summer. | Oct 15 |
| Strawberry | — | Apr 9–Jun 4 | 189 | perennial: A perennial: plant Apr 9; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 16 | May 21–May 28 | 105 | fits: 75 days to maturity, 105 available after May 21. | Jun 6 |
| Pumpkin | Apr 30 | May 28–May 28 | 98 | head-start: Even planted out May 28, the outdoor season is about 2 days short; choose an early variety or grow under cover. | — |
| Cauliflower | Apr 2 | May 7–May 21 | 147 | fits: 75 days to maturity, 147 available after May 7. | Jul 4 |
| Swiss Chard | Mar 19 | Apr 30–Apr 30 | 154 | two-plantings: Plant Apr 30 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Arugula | — | Mar 19–Jun 11 | 210 | two-plantings: Plant Mar 19 and again by Aug 22; both mature before Oct 15. | Aug 22 |
| Brussel Sprouts | Mar 19 | Apr 16–Apr 30 | 182 | fits: 100 days to maturity, 182 available after Apr 16. | Jun 23 |
| Butternut Squash | Apr 30 | May 28–Jun 4 | 98 | head-start: Even planted out May 28, the outdoor season is about 2 days short; choose an early variety or grow under cover. | — |
| Eggplant | Mar 26 | May 28–Jun 4 | 91 | fits: 70 days to maturity, 91 available after May 28. | Jun 4 |
| Okra | Apr 16 | May 21–May 28 | 112 | fits: 55 days to maturity, 112 available after May 21. | Jul 3 |
| Basil | Apr 9 | Jun 4–Jun 4 | 98 | fits: 60 days to maturity, 98 available after Jun 4. | Jun 28 |
| Cilantro | — | Apr 16–May 7 | 168 | two-plantings: Plant Apr 16 and again by Jul 29; both mature before Oct 1. | Jul 29 |
| Parsley | Mar 5 | May 21–May 28 | 133 | fits: 70 days to maturity, 133 available after May 21. | Jul 9 |
| Celery | Mar 5 | May 21–Jun 4 | 133 | fits: 120 days to maturity, 133 available after May 21. | — |
| Scallions | Mar 5 | Apr 16–Apr 30 | 182 | two-plantings: Plant Apr 16 and again by Aug 2; both mature before Oct 15. | Aug 2 |
| Turnip | — | Apr 16–Apr 30 | 182 | two-plantings: Plant Apr 16 and again by Aug 12; both mature before Oct 15. | Aug 12 |
| Kohlrabi | — | Apr 2–Apr 16 | 196 | two-plantings: Plant Apr 2 and again by Aug 7; both mature before Oct 15. | Aug 7 |
| Bok Choy | Apr 16 | May 7–May 14 | 147 | two-plantings: Plant May 7 and again by Aug 3; both mature before Oct 1. | Aug 3 |
| Collards | Mar 5 | Apr 16–Apr 30 | 182 | two-plantings: Plant Apr 16 and again by Aug 2; both mature before Oct 15. | Aug 2 |
| Cantaloupe | Apr 30 | May 28–Jun 4 | 91 | fits: 85 days to maturity, 91 available after May 28. | — |
| Chives | Feb 19 | May 21–May 28 | 147 | fits: 90 days to maturity, 147 available after May 21. | — |
| Dill | — | Mar 19–Jun 11 | 196 | two-plantings: Plant Mar 19 and again by Jul 24; both mature before Oct 1. | Jul 24 |
| Oregano | Mar 5 | May 21–May 28 | 147 | fits: 80 days to maturity, 147 available after May 21. | — |
| Rosemary | Feb 19 | May 21–May 28 | 133 | fits: 80 days to maturity, 133 available after May 21. | — |
| Sage | Mar 19 | May 21–May 28 | 147 | fits: 75 days to maturity, 147 available after May 21. | — |
| Thyme | Mar 5 | May 21–May 28 | 147 | fits: 90 days to maturity, 147 available after May 21. | — |
| Calendula | Apr 2 | Apr 30–May 14 | 154 | two-plantings: Plant Apr 30 and again by Jul 29; both mature before Oct 1. | Jul 29 |
| Cosmos | Apr 16 | May 14–May 28 | 119 | fits: 60 days to maturity, 119 available after May 14. | Jun 28 |
| Lavender | Feb 19 | May 14–May 28 | 154 | fits: 90 days to maturity, 154 available after May 14. | — |
| Marigolds | Apr 2 | May 14–May 21 | 119 | two-plantings: Plant May 14 and again by Jul 8; both mature before Sep 10. | Jul 8 |
| Melons | Apr 30 | May 28–Jun 4 | 91 | fits: 85 days to maturity, 91 available after May 28. | — |
| Mint | — | May 14–May 28 | 154 | fits: 90 days to maturity, 154 available after May 14. | — |
| Nasturtiums | Apr 16 | May 14–May 21 | 119 | fits: 55 days to maturity, 119 available after May 14. | Jul 3 |
| Pole Beans | — | May 21–Jun 4 | 112 | fits: 65 days to maturity, 112 available after May 21. | Jun 23 |
| Spaghetti Squash | Apr 30 | May 28–Jun 4 | 98 | fits: 90 days to maturity, 98 available after May 28. | — |
| Sunflowers | — | May 14–May 28 | 119 | fits: 70 days to maturity, 119 available after May 14. | Jun 18 |
| Tomatillos | Mar 19 | May 21–May 28 | 98 | fits: 75 days to maturity, 98 available after May 21. | May 30 |
| Watermelon | Apr 30 | May 21–May 28 | 98 | fits: 80 days to maturity, 98 available after May 21. | May 25 |
| Yellow Squash | Apr 30 | May 28–Jun 4 | 105 | fits: 55 days to maturity, 105 available after May 28. | Jul 3 |
| Zinnias | Apr 16 | May 14–May 28 | 119 | fits: 60 days to maturity, 119 available after May 14. | Jun 28 |
Month by month in Rupert
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 19), Lavender (Feb 19), Onion (Feb 19), Rosemary (Feb 19). |
| March | Start indoors: Celery (Mar 5), Collards (Mar 5), Kale (Mar 5), Oregano (Mar 5), Parsley (Mar 5), Scallions (Mar 5), +9 more. Direct sow from: Arugula (Mar 19), Beets (Mar 19), Dill (Mar 19), Peas (Mar 19), Radish (Mar 19), Spinach (Mar 19). |
| April | Start indoors: Calendula (Apr 2), Cauliflower (Apr 2), Marigolds (Apr 2), Pepper (Apr 2), Basil (Apr 9), Tomato (Apr 9), +15 more. Direct sow from: Kohlrabi (Apr 2), Cilantro (Apr 16), Turnip (Apr 16), Carrots (Apr 23), Potatoes (Apr 30). Transplant from: Broccoli (Apr 16), Brussel Sprouts (Apr 16), Cabbage (Apr 16), Collards (Apr 16), Kale (Apr 16), Lettuce (Apr 16), +4 more. Plant: Strawberry (Apr 9). |
| May | Direct sow from: Sunflowers (May 14), Beans (May 21), Pole Beans (May 21). Transplant from: Bok Choy (May 7), Cauliflower (May 7), Cosmos (May 14), Lavender (May 14), Marigolds (May 14), Mint (May 14), +24 more. Last frost around May 14. Last sowing dates: Watermelon (May 25), Pepper (May 30), Tomatillos (May 30). |
| June | Transplant from: Basil (Jun 4). Last sowing dates: Eggplant (Jun 4), Corn (Jun 6), Sunflowers (Jun 18), Brussel Sprouts (Jun 23), Pole Beans (Jun 23), Basil (Jun 28), +4 more. |
| July | Last sowing dates: Nasturtiums (Jul 3), Okra (Jul 3), Yellow Squash (Jul 3), Zucchini (Jul 3), Cauliflower (Jul 4), Beans (Jul 5), +10 more. |
| August | Last sowing dates: Collards (Aug 2), Scallions (Aug 2), Bok Choy (Aug 3), Lettuce (Aug 3), Kale (Aug 7), Kohlrabi (Aug 7), +4 more. |
| September | Direct sow from: Garlic (Sep 24). First frost around September 24. |
| October | Last sowing dates: Garlic (Oct 15). |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| 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 Rupert, ID (ZIP 83350)?
The median last spring frost date for Rupert, ID (ZIP code 83350) is around May 14. 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 27; one in ten it runs past June 2.
What is the first fall frost date in Rupert, ID?
The median first fall frost date for Rupert, ID is around September 24. 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 10 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Rupert, ID?
The frost-free growing season in Rupert is about 133 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 Rupert (133 frost-free days, a moderate season), 37 of 56 planner crops fit outright, 16 get two plantings, 2 need an indoor start, 1 crop is perennial.
What USDA hardiness zone is Rupert, ID?
Rupert, ID is in USDA hardiness zone 6a (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 Rupert, ID?
Start tomatoes indoors Apr 9 and plant out May 28 in Rupert. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Rupert?
Two: plant Apr 16 and again by Aug 3; both mature before Oct 1.
When do I plant garlic in Rupert?
Sep 24 to Oct 15; it overwinters and is ready the following summer.
Can I grow Butternut Squash in Rupert?
Yes, with help. Even planted out May 28, the outdoor season is about 2 days short; choose an early variety or grow under cover.
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