Frost Dates for Caldwell, ID 83607
Last spring frost April 28 · First fall frost October 10 · 165 frost-free days · USDA Zone 7a
ZIP 83607 has about 35,500 people, one of 2 ZIP codes in Caldwell.
Moderate season: 165 frost-free days. Spring frost risk spans April 4–May 25 (51 days). Fall frost risk spans September 24–October 26 (32 days).
Frost probability for 83607
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 25 | April 28 | April 4 |
| Fall (first frost) | September 24 | October 10 | October 26 |
Dates come from NOAA 1971–2000 freeze probabilities at DEER FLAT DAM (15.0 km away); the 50% date is the median year.
Which crops fit a 165-day season in Caldwell
In Caldwell (165 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 24 | May 12–May 19 | 123 | fits: 80 days to maturity, 123 available after May 12. | Jun 10 |
| Pepper | Mar 17 | May 12–May 19 | 123 | fits: 75 days to maturity, 123 available after May 12. | Jun 15 |
| Lettuce | Mar 3 | Mar 31–Apr 7 | 200 | two-plantings: Plant Mar 31 and again by Aug 19; both mature before Oct 17. | Aug 19 |
| Carrots | — | Apr 7–Apr 14 | 207 | fits: 70 days to maturity, 207 available after Apr 7. | Aug 8 |
| Cucumber | Apr 7 | May 12–May 19 | 137 | two-plantings: Plant May 12 and again by Jul 14; both mature before Sep 26. | Jul 14 |
| Beans | — | May 5–May 19 | 151 | two-plantings: Plant May 5 and again by Jul 21; both mature before Oct 3. | Jul 21 |
| Peas | — | Mar 3–May 12 | 228 | fits: 65 days to maturity, 228 available after Mar 3. | Jul 30 |
| Zucchini | Apr 14 | May 12–May 19 | 137 | two-plantings: Plant May 12 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Onion | Feb 3 | Mar 31–Apr 14 | 200 | fits: 100 days to maturity, 200 available after Mar 31. | — |
| Spinach | — | Mar 3–Apr 21 | 242 | two-plantings: Plant Mar 3 and again by Sep 7; both mature before Oct 31. | Sep 7 |
| Kale | Feb 17 | Mar 31–Apr 14 | 214 | two-plantings: Plant Mar 31 and again by Aug 23; both mature before Oct 31. | Aug 23 |
| Broccoli | Mar 3 | Mar 31–Apr 14 | 200 | fits: 80 days to maturity, 200 available after Mar 31. | Jul 15 |
| Cabbage | Mar 3 | Mar 31–Apr 14 | 214 | fits: 70 days to maturity, 214 available after Mar 31. | Aug 8 |
| Radish | — | Mar 3–May 26 | 228 | two-plantings: Plant Mar 3 and again by Sep 8; both mature before Oct 17. | Sep 8 |
| Beets | — | Mar 3–May 26 | 228 | two-plantings: Plant Mar 3 and again by Aug 9; both mature before Oct 17. | Aug 9 |
| Potatoes | — | Apr 14–Apr 21 | 186 | fits: 90 days to maturity, 186 available after Apr 14. | — |
| Garlic | — | Oct 10 | 270 | overwinter: Plant Oct 10 to Oct 31; harvest the following summer. | Oct 31 |
| Strawberry | — | Mar 24–May 19 | 221 | perennial: A perennial: plant Mar 24; it fruits from the following year and keeps producing for several years. | — |
| Corn | Mar 31 | May 5–May 12 | 137 | fits: 75 days to maturity, 137 available after May 5. | Jun 22 |
| Pumpkin | Apr 14 | May 12–May 12 | 130 | fits: 100 days to maturity, 130 available after May 12. | May 28 |
| Cauliflower | Mar 17 | Apr 21–May 5 | 179 | fits: 75 days to maturity, 179 available after Apr 21. | Jul 20 |
| Swiss Chard | Mar 3 | Apr 14–Apr 14 | 186 | two-plantings: Plant Apr 14 and again by Aug 9; both mature before Oct 17. | Aug 9 |
| Arugula | — | Mar 3–May 26 | 242 | two-plantings: Plant Mar 3 and again by Sep 7; both mature before Oct 31. | Sep 7 |
| Brussel Sprouts | Mar 3 | Mar 31–Apr 14 | 214 | fits: 100 days to maturity, 214 available after Mar 31. | Jul 9 |
| Butternut Squash | Apr 14 | May 12–May 19 | 130 | fits: 100 days to maturity, 130 available after May 12. | May 28 |
| Eggplant | Mar 10 | May 12–May 19 | 123 | fits: 70 days to maturity, 123 available after May 12. | Jun 20 |
| Okra | Mar 31 | May 5–May 12 | 144 | two-plantings: Plant May 5 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Basil | Mar 24 | May 19–May 19 | 130 | fits: 60 days to maturity, 130 available after May 19. | Jul 14 |
| Cilantro | — | Mar 31–Apr 21 | 200 | two-plantings: Plant Mar 31 and again by Aug 14; both mature before Oct 17. | Aug 14 |
| Parsley | Feb 17 | May 5–May 12 | 165 | fits: 70 days to maturity, 165 available after May 5. | Jul 25 |
| Celery | Feb 17 | May 5–May 19 | 165 | fits: 120 days to maturity, 165 available after May 5. | Jun 5 |
| Scallions | Feb 17 | Mar 31–Apr 14 | 214 | two-plantings: Plant Mar 31 and again by Aug 18; both mature before Oct 31. | Aug 18 |
| Turnip | — | Mar 31–Apr 14 | 214 | two-plantings: Plant Mar 31 and again by Aug 28; both mature before Oct 31. | Aug 28 |
| Kohlrabi | — | Mar 17–Mar 31 | 228 | two-plantings: Plant Mar 17 and again by Aug 23; both mature before Oct 31. | Aug 23 |
| Bok Choy | Mar 31 | Apr 21–Apr 28 | 179 | two-plantings: Plant Apr 21 and again by Aug 19; both mature before Oct 17. | Aug 19 |
| Collards | Feb 17 | Mar 31–Apr 14 | 214 | two-plantings: Plant Mar 31 and again by Aug 18; both mature before Oct 31. | Aug 18 |
| Cantaloupe | Apr 14 | May 12–May 19 | 123 | fits: 85 days to maturity, 123 available after May 12. | Jun 5 |
| Chives | Feb 3 | May 5–May 12 | 179 | fits: 90 days to maturity, 179 available after May 5. | — |
| Dill | — | Mar 3–May 26 | 228 | two-plantings: Plant Mar 3 and again by Aug 9; both mature before Oct 17. | Aug 9 |
| Oregano | Feb 17 | May 5–May 12 | 179 | fits: 80 days to maturity, 179 available after May 5. | — |
| Rosemary | Feb 3 | May 5–May 12 | 165 | fits: 80 days to maturity, 165 available after May 5. | — |
| Sage | Mar 3 | May 5–May 12 | 179 | fits: 75 days to maturity, 179 available after May 5. | — |
| Thyme | Feb 17 | May 5–May 12 | 179 | fits: 90 days to maturity, 179 available after May 5. | — |
| Calendula | Mar 17 | Apr 14–Apr 28 | 186 | two-plantings: Plant Apr 14 and again by Aug 14; both mature before Oct 17. | Aug 14 |
| Cosmos | Mar 31 | Apr 28–May 12 | 151 | two-plantings: Plant Apr 28 and again by Jul 14; both mature before Sep 26. | Jul 14 |
| Lavender | Feb 3 | Apr 28–May 12 | 186 | fits: 90 days to maturity, 186 available after Apr 28. | — |
| Marigolds | Mar 17 | Apr 28–May 5 | 151 | two-plantings: Plant Apr 28 and again by Jul 24; both mature before Sep 26. | Jul 24 |
| Melons | Apr 14 | May 12–May 19 | 123 | fits: 85 days to maturity, 123 available after May 12. | Jun 5 |
| Mint | — | Apr 28–May 12 | 186 | fits: 90 days to maturity, 186 available after Apr 28. | — |
| Nasturtiums | Mar 31 | Apr 28–May 5 | 151 | two-plantings: Plant Apr 28 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Pole Beans | — | May 5–May 19 | 144 | fits: 65 days to maturity, 144 available after May 5. | Jul 9 |
| Spaghetti Squash | Apr 14 | May 12–May 19 | 130 | fits: 90 days to maturity, 130 available after May 12. | Jun 7 |
| Sunflowers | — | Apr 28–May 12 | 151 | fits: 70 days to maturity, 151 available after Apr 28. | Jul 4 |
| Tomatillos | Mar 3 | May 5–May 12 | 130 | fits: 75 days to maturity, 130 available after May 5. | Jun 15 |
| Watermelon | Apr 14 | May 5–May 12 | 130 | fits: 80 days to maturity, 130 available after May 5. | Jun 10 |
| Yellow Squash | Apr 14 | May 12–May 19 | 137 | two-plantings: Plant May 12 and again by Jul 19; both mature before Sep 26. | Jul 19 |
| Zinnias | Mar 31 | Apr 28–May 12 | 151 | two-plantings: Plant Apr 28 and again by Jul 14; both mature before Sep 26. | Jul 14 |
Month by month in Caldwell
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 3), Lavender (Feb 3), Onion (Feb 3), Rosemary (Feb 3), Celery (Feb 17), Collards (Feb 17), +5 more. |
| March | Start indoors: Broccoli (Mar 3), Brussel Sprouts (Mar 3), Cabbage (Mar 3), Lettuce (Mar 3), Sage (Mar 3), Swiss Chard (Mar 3), +14 more. Direct sow from: Arugula (Mar 3), Beets (Mar 3), Dill (Mar 3), Peas (Mar 3), Radish (Mar 3), Spinach (Mar 3), +3 more. Transplant from: Broccoli (Mar 31), Brussel Sprouts (Mar 31), Cabbage (Mar 31), Collards (Mar 31), Kale (Mar 31), Lettuce (Mar 31), +2 more. Plant: Strawberry (Mar 24). |
| April | Start indoors: Cucumber (Apr 7), Butternut Squash (Apr 14), Cantaloupe (Apr 14), Melons (Apr 14), Pumpkin (Apr 14), Spaghetti Squash (Apr 14), +3 more. Direct sow from: Carrots (Apr 7), Potatoes (Apr 14), Sunflowers (Apr 28). Transplant from: Calendula (Apr 14), Swiss Chard (Apr 14), Bok Choy (Apr 21), Cauliflower (Apr 21), Cosmos (Apr 28), Lavender (Apr 28), +4 more. Last frost around April 28. |
| May | Direct sow from: Beans (May 5), Pole Beans (May 5). Transplant from: Celery (May 5), Chives (May 5), Corn (May 5), Okra (May 5), Oregano (May 5), Parsley (May 5), +17 more. Last sowing dates: Butternut Squash (May 28), Pumpkin (May 28). |
| June | Last sowing dates: Cantaloupe (Jun 5), Celery (Jun 5), Melons (Jun 5), Spaghetti Squash (Jun 7), Tomato (Jun 10), Watermelon (Jun 10), +4 more. |
| July | Last sowing dates: Sunflowers (Jul 4), Brussel Sprouts (Jul 9), Pole Beans (Jul 9), Basil (Jul 14), Cosmos (Jul 14), Cucumber (Jul 14), +11 more. |
| August | Last sowing dates: Cabbage (Aug 8), Carrots (Aug 8), Beets (Aug 9), Dill (Aug 9), Swiss Chard (Aug 9), Calendula (Aug 14), +8 more. |
| September | Last sowing dates: Arugula (Sep 7), Spinach (Sep 7), Radish (Sep 8). |
| October | Direct sow from: Garlic (Oct 10). First frost around October 10. Last sowing dates: Garlic (Oct 31). |
| 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 Caldwell, ID (ZIP 83607)?
The median last spring frost date for Caldwell, ID (ZIP code 83607) is around April 28. 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 4; one in ten it runs past May 25.
What is the first fall frost date in Caldwell, ID?
The median first fall frost date for Caldwell, ID is around October 10. 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 24 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Caldwell, ID?
The frost-free growing season in Caldwell is about 165 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 Caldwell (165 frost-free days, a moderate season), 31 of 56 planner crops fit outright, 24 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Caldwell, ID?
Caldwell, 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 Caldwell, ID?
Start tomatoes indoors Mar 24 and plant out May 12 in Caldwell. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Caldwell?
Two: plant Mar 31 and again by Aug 19; both mature before Oct 17.
When do I plant garlic in Caldwell?
Oct 10 to Oct 31; it overwinters and is ready the following summer.
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