Nampa, Idaho planting calendar and frost dates
Nampa is in USDA hardiness zone 7a. The last spring frost typically comes around April 24 and the first fall frost around October 21, giving about 179 frost-free days a year.
- Hardiness zone
- Zone 7a
- Typical last frost
- April 24
- Typical first frost
- October 21
- Frost-free season
- 179 days
Frost dates in Nampa
Last spring frost
- April 4Risky: frost later than this in 9 years out of 10
- April 24Typical: a later frost in half of years
- May 9Safe: a later frost only 1 year in 10
First fall frost
- October 5Risky: frost earlier than this 1 year in 10
- October 21Typical: an earlier frost in half of years
- November 5Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 179 days. Frost here means a low of 32°F at the weather station. A hard freeze (28°F), which damages most hardy crops too, typically ends around April 2 and returns around October 31.
NOAA U.S. Climate Normals 1991-2020 for Boise Air Terminal, 3.7 miles SSW of the city center and 114 feet higher. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers. Nampa shares this station with Boise City, so the two cities have the same frost dates and planting calendar.
What to plant each month in Nampa
January
Start indoors: collard greens, leeks, onions, petunias, ranunculus
February
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, collard greens, ginger, kale, leeks, lettuce, marigolds, onions, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons
March
Start indoors: basil, black-eyed susans, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, lettuce, marigolds, nasturtiums, peppers, ranunculus, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: beets, black-eyed susans, blackberries, blueberries, broccoli, cauliflower, chives, cilantro, collard greens, figs, garlic, gladioli, grapes, grass seed, hollyhocks, kale, leeks, onions, peas, poppies, radishes, ranunculus, raspberries, rhubarb, roses, spinach, strawberries, swiss chard, turnips, wildflowers
April
Start indoors: basil, cantaloupes, cosmos, cucumbers, okra, pumpkins, ranunculus, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garden mums, gladioli, grapes, green onions, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, onions, oregano, parsley, petunias, potatoes, radishes, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, swiss chard, thyme, turnips
May
Start indoors: cosmos, cucumbers, okra, pumpkins, winter squash, zinnias, zucchini
Plant or sow outdoors: asparagus, basil, cantaloupes, chives, cilantro, cucumbers, dahlias, dill, eggplants, garden mums, ginger, gladioli, grapes, green beans, green onions, kentucky bluegrass, lavenders, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, peppers, perennial ryegrass, petunias, pumpkins, ranunculus, rosemary, sage, spinach, st. augustinegrass, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, tomatoes, watermelons, winter squash, zucchini
June
Start indoors: zinnias
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, sweet potatoes, zinnias, zoysiagrass
July
Plant or sow outdoors: bermudagrass, centipedegrass, st. augustinegrass, zinnias, zoysiagrass
Plant for fall: bearded irises, brussels sprouts, carrots, collard greens, lettuce, peas, snapdragons, swiss chard
August
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, cauliflower, clematis, collard greens, coneflowers, daylilies, hostas, hydrangeas, kale, lettuce, peas, radishes, roses, saffron, snapdragons, spinach, swiss chard, turnips
September
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, hydrangeas, kale, kentucky bluegrass, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, roses, saffron, spinach, tall fescue, tulips, turnips
October
Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
November
Plant for fall: crocuses, garlic, hyacinths, ornamental alliums, tulips
Frost dates and zones by ZIP code in Nampa
All 3 of Nampa's main ZIP codes take their frost dates from Boise Air Terminal, so the dates on this page apply across the city. Every one of them is in zone 7a.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 83651 | 7a | Boise Air Terminal, 3.7 mi SSW | Apr 24 | Oct 21 |
| 83686 | 7a | Boise Air Terminal, 3.7 mi SSW | Apr 24 | Oct 21 |
| 83687 | 7a | Boise Air Terminal, 3.7 mi SSW | Apr 24 | Oct 21 |
Boise Air Terminal also supplies the frost dates for Boise City and Meridian, so their planting calendars match Nampa's.
Planting dates for popular crops in Nampa
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 21 to Apr 4 | May 16 to 30 | — |
| Strawberries | — | Mar 13 to 27 | — |
| Lettuce | Feb 27 to Mar 13 | Apr 17 to May 1 | Jul 22 to Aug 26 |
| Cilantro | Mar 13 to 27 | Apr 24 to May 1 | — |
| Basil | Mar 28 to Apr 11 | May 16 to 23 | — |
| Potatoes | — | Apr 13 to 20 | — |
| Garlic | — | Mar 13 to 27 | Oct 21 to Nov 4 |
| Onions | Jan 2 to Feb 13 | Mar 27 to Apr 10 | — |
| Cucumbers | Apr 18 to May 2 | May 16 to 30 | — |
| Pumpkins | Apr 18 to May 2 | May 16 to 30 | — |
| Peppers | Feb 28 to Mar 28 | May 16 to 30 | — |
| Carrots | — | Apr 3 to 24 | Jul 29 to Aug 19 |
| Sweet Potatoes | — | Jun 6 to 13 | — |
| Watermelons | Apr 11 to 25 | May 16 to 30 | — |
| Sweet Corn | — | Apr 24 to May 8 | — |
| Green Beans | — | May 16 to 30 | — |
| Zucchini | Apr 18 to May 2 | May 16 to 30 | — |
| Broccoli | Feb 6 to 27 | Mar 27 to Apr 10 | Aug 5 to Sep 2 |
| Peas | — | Mar 13 to 27 | Jul 29 to Aug 12 |
| Spinach | Mar 13 to 20 | Apr 17 to May 1 | Aug 12 to Sep 16 |
| Sunflowers | — | Apr 24 to May 15 | — |
| Zinnias | May 27 to Jun 3 | Jun 24 to Jul 8 | — |
| Tulips | — | — | Sep 9 to Nov 4 |
| Daffodils | — | — | Sep 9 to Oct 21 |
| Grass Seed | — | Mar 13 to 27 | Sep 9 to 23 |
Nearby cities
- Caldwell, ID zone 7a, last frost Apr 29
- Meridian, ID zone 7a, last frost Apr 24
- Boise City, ID zone 6b, last frost Apr 24
- Twin Falls, ID zone 6b, last frost May 9
- Pocatello, ID zone 6a, last frost May 16
- Kennewick, WA zone 7b, last frost Mar 28
Planting in IdahoAbout zone 7aPrintable calendar for Nampa
Questions
When is the last frost in Nampa?
Around April 24 in a typical year, based on NOAA's 1991-2020 records for Boise Air Terminal. There is still a 1 in 10 chance of frost after May 9.
What planting zone is Nampa in?
USDA hardiness zone 7a (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Nampa?
Start seeds indoors March 21 to April 4 and set plants out May 16 to 30.
When is the first frost in Nampa?
Around October 21 in a typical year, and before October 5 about 1 year in 10.