Kennewick, Washington planting calendar and frost dates
Kennewick is in USDA hardiness zone 7b. The last spring frost typically comes around March 28 and the first fall frost around October 30, giving about 216 frost-free days a year.
- Hardiness zone
- Zone 7b
- Typical last frost
- March 28
- Typical first frost
- October 30
- Frost-free season
- 216 days
Frost dates in Kennewick
Last spring frost
- March 9Risky: frost later than this in 9 years out of 10
- March 28Typical: a later frost in half of years
- April 10Safe: a later frost only 1 year in 10
First fall frost
- October 18Risky: frost earlier than this 1 year in 10
- October 30Typical: an earlier frost in half of years
- November 15Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 216 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 March 8 and returns around November 11.
NOAA U.S. Climate Normals 1991-2020 for Kennewick, 3.6 miles E of the city center and 118 feet lower. Low-lying and rural spots often frost later in spring and earlier in fall than airports and city centers.
What to plant each month in Kennewick
January
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, chives, collard greens, kale, leeks, lettuce, marigolds, onions, oregano, parsley, petunias, ranunculus, rosemary, sage, snapdragons
February
Start indoors: black-eyed susans, cabbages, cauliflower, chives, cilantro, collard greens, ginger, lettuce, marigolds, nasturtiums, peppers, ranunculus, sage, snapdragons, spinach, swiss chard
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
March
Start indoors: basil, celery, eggplants, ginger, peppers, ranunculus, tomatoes
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
April
Start indoors: basil, cantaloupes, cosmos, cucumbers, okra, pumpkins, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, chives, cilantro, dahlias, dill, garden mums, ginger, gladioli, grapes, green onions, kentucky bluegrass, lavenders, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, perennial ryegrass, petunias, potatoes, ranunculus, rosemary, sage, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme
May
Start indoors: zinnias
Plant or sow outdoors: asparagus, basil, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, ginger, green beans, green onions, kentucky bluegrass, okra, peanuts, peppers, perennial ryegrass, pumpkins, st. augustinegrass, sweet peas, sweet potatoes, tall fescue, tomatoes, watermelons, winter squash, zoysiagrass, zucchini
June
Plant or sow outdoors: bermudagrass, celery, centipedegrass, cosmos, green onions, okra, peanuts, st. augustinegrass, sweet potatoes, zinnias, zoysiagrass
July
Plant or sow outdoors: zinnias
Plant for fall: brussels sprouts, collard greens, lettuce, potatoes, sweet corn, swiss chard
August
Plant for fall: bearded irises, beets, broccoli, cabbages, carrots, cauliflower, collard greens, daylilies, kale, lettuce, peas, radishes, snapdragons, spinach, sweet corn, swiss chard, turnips
September
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, cauliflower, clematis, coneflowers, crocuses, daffodils, daylilies, grass seed, hostas, hydrangeas, kale, kentucky bluegrass, lettuce, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, roses, saffron, snapdragons, spinach, tall fescue, tulips, turnips
October
Plant for fall: crocuses, daffodils, daylilies, garlic, grass seed, hostas, hyacinths, kale, kentucky bluegrass, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, saffron, tall fescue, tulips
November
Plant for fall: crocuses, garlic, hyacinths, ornamental alliums, tulips
December
Start indoors: onions
Frost dates and zones by ZIP code in Kennewick
Kennewick's 3 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from March 28 in 99336 to April 26 in 99337. Every one of them is in zone 7b.
Planting dates for popular crops in Kennewick
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Mar 11 to 25 | May 6 to 20 | — |
| Strawberries | — | Feb 14 to 28 | — |
| Lettuce | Jan 31 to Feb 14 | Mar 21 to Apr 4 | Jul 31 to Sep 4 |
| Cilantro | Feb 14 to 28 | Mar 28 to Apr 4 | — |
| Basil | Mar 18 to Apr 1 | May 6 to 13 | — |
| Potatoes | — | Mar 28 to Apr 4 | Jul 10 to 17 |
| Garlic | — | Feb 14 to 28 | Oct 30 to Nov 13 |
| Onions | Dec 6 to Jan 17 | Feb 28 to Mar 14 | — |
| Cucumbers | Apr 8 to 22 | May 6 to 20 | — |
| Pumpkins | Apr 8 to 22 | May 6 to 20 | — |
| Peppers | Feb 18 to Mar 18 | May 6 to 20 | — |
| Carrots | — | Mar 7 to 28 | Aug 7 to 28 |
| Sweet Potatoes | — | May 25 to Jun 1 | — |
| Watermelons | Apr 1 to 15 | May 6 to 20 | — |
| Sweet Corn | — | Mar 28 to Apr 11 | Jul 24 to Aug 7 |
| Green Beans | — | May 6 to 20 | — |
| Zucchini | Apr 8 to 22 | May 6 to 20 | — |
| Broccoli | Jan 10 to 31 | Feb 28 to Mar 14 | Aug 14 to Sep 11 |
| Peas | — | Feb 14 to 28 | Aug 7 to 21 |
| Spinach | Feb 14 to 21 | Mar 21 to Apr 4 | Aug 21 to Sep 25 |
| Sunflowers | — | Mar 28 to Apr 18 | — |
| Zinnias | May 23 to 30 | Jun 20 to Jul 4 | — |
| Tulips | — | — | Sep 18 to Nov 13 |
| Daffodils | — | — | Sep 18 to Oct 30 |
| Grass Seed | — | Feb 14 to 28 | Sep 18 to Oct 2 |
Nearby cities
- Pasco, WA zone 7a, last frost Apr 7
- Richland, WA zone 7b, last frost Apr 6
- Yakima, WA zone 7a, last frost May 8
- Spokane, WA zone 6b, last frost Apr 26
- Spokane Valley, WA zone 7a, last frost Apr 26
- Coeur d'Alene, ID zone 6b, last frost Apr 22
Planting in WashingtonAbout zone 7bPrintable calendar for Kennewick
Questions
When is the last frost in Kennewick?
Around March 28 in a typical year, based on NOAA's 1991-2020 records for Kennewick. There is still a 1 in 10 chance of frost after April 10.
What planting zone is Kennewick in?
USDA hardiness zone 7b (2023 map). The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in Kennewick?
Start seeds indoors March 11 to 25 and set plants out May 6 to 20.
When is the first frost in Kennewick?
Around October 30 in a typical year, and before October 18 about 1 year in 10.