St. Charles, Missouri planting calendar and frost dates
St. Charles is in USDA hardiness zone 6b. The last spring frost typically comes around April 2 and the first fall frost around November 4, giving about 215 frost-free days a year.
- Typical last frost
- April 2
- Typical first frost
- November 4
- Frost-free season
- 215 days
Frost dates in St. Charles
Last spring frost
- March 17Risky: frost later than this in 9 years out of 10
- April 2Typical: a later frost in half of years
- April 17Safe: a later frost only 1 year in 10
First fall frost
- October 23Risky: frost earlier than this 1 year in 10
- November 4Typical: an earlier frost in half of years
- November 18Late: frost before this in 9 years out of 10
The growing season between the typical last and first frosts is about 215 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 23 and returns around November 13.
NOAA U.S. Climate Normals 1991-2020 for St Louis Lambert International Airport, 8.7 miles SSE of the city center. 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 St. Charles
January
Start indoors: broccoli, cabbages, cauliflower, collard greens, kale, leeks, onions, oregano, parsley, petunias, ranunculus, rosemary, snapdragons
February
Start indoors: black-eyed susans, broccoli, cabbages, cauliflower, celery, chives, cilantro, collard greens, eggplants, ginger, leeks, lettuce, marigolds, nasturtiums, oregano, parsley, peppers, petunias, ranunculus, rosemary, sage, snapdragons, spinach, swiss chard, tomatoes
Plant or sow outdoors: black-eyed susans, blueberries, garlic, grapes, grass seed, hollyhocks, kale, onions, peas, poppies, raspberries, rhubarb, strawberries, turnips, wildflowers
March
Start indoors: basil, cantaloupes, cilantro, cosmos, cucumbers, eggplants, marigolds, nasturtiums, okra, peppers, pumpkins, ranunculus, tomatoes, watermelons, winter squash, zucchini
Plant or sow outdoors: asparagus, beets, black-eyed susans, blackberries, blueberries, broccoli, cabbages, carrots, cauliflower, chives, cilantro, collard greens, dahlias, dill, figs, garlic, gladioli, grapes, grass seed, green onions, hollyhocks, kale, leeks, lettuce, onions, parsley, peas, poppies, potatoes, radishes, ranunculus, raspberries, rhubarb, roses, snapdragons, spinach, strawberries, swiss chard, turnips, wildflowers
April
Start indoors: cantaloupes, cosmos, cucumbers, okra, pumpkins, watermelons, winter squash, zinnias, zucchini
Plant or sow outdoors: asparagus, basil, beets, cantaloupes, carrots, chives, cilantro, cucumbers, dahlias, dill, eggplants, figs, garden mums, ginger, gladioli, grapes, green beans, green onions, kentucky bluegrass, lavenders, leeks, lettuce, lilies, marigolds, mints, nasturtiums, oregano, parsley, peppers, perennial ryegrass, petunias, potatoes, pumpkins, ranunculus, rosemary, roses, sage, snapdragons, spinach, sunflowers, sweet corn, sweet peas, swiss chard, tall fescue, thyme, tomatoes, watermelons, winter squash, zucchini
May
Start indoors: zinnias
Plant or sow outdoors: asparagus, bermudagrass, cantaloupes, celery, centipedegrass, cosmos, cucumbers, eggplants, green beans, green onions, okra, peanuts, peppers, pumpkins, st. augustinegrass, sweet potatoes, tomatoes, watermelons, winter squash, zinnias, zoysiagrass, zucchini
June
Plant or sow outdoors: bermudagrass, centipedegrass, green onions, st. augustinegrass, zinnias, zoysiagrass
July
Plant for fall: brussels sprouts, peppers, potatoes, sweet corn, tomatoes
August
Plant for fall: bearded irises, beets, broccoli, brussels sprouts, cabbages, carrots, cauliflower, collard greens, cucumbers, green beans, lettuce, peas, peppers, radishes, snapdragons, spinach, sweet corn, swiss chard, turnips, zucchini
September
Plant for fall: azaleas, bearded irises, beets, broccoli, cabbages, carrots, 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, swiss chard, tall fescue, tulips, turnips
October
Plant for fall: crocuses, daffodils, daylilies, grass seed, hostas, hyacinths, kale, kentucky bluegrass, lilies, ornamental alliums, peonies, perennial ryegrass, radishes, saffron, tall fescue, tulips
November
Plant for fall: crocuses, daffodils, garlic, hyacinths, lilies, ornamental alliums, peonies, tulips
December
Start indoors: onions
Frost dates and zones by ZIP code in St. Charles
St. Charles's 2 main ZIP codes take their frost dates from 2 different NOAA stations: the typical last frost ranges from April 2 in 63301 to April 4 in 63303. The hardiness zone is 6b in 63301, and 7a in 63303.
| ZIP code | Zone | Weather station | Typical last frost | Typical first frost |
|---|---|---|---|---|
| 63301 | 6b | St Louis Lambert International Airport, 8.7 mi SSE | Apr 2 | Nov 4 |
| 63303 | 7a | St Charles 7 Ssw, 3.9 mi SSE | Apr 4 | Oct 29 |
St Louis Lambert International Airport also supplies the frost dates for Florissant, so their planting calendars match St. Charles's.
Planting dates for popular crops in St. Charles
| Plant | Start indoors | Plant or sow outdoors | Fall planting |
|---|---|---|---|
| Tomatoes | Feb 26 to Mar 12 | Apr 23 to May 7 | Jul 22 to 29 |
| Strawberries | — | Feb 19 to Mar 5 | — |
| Lettuce | Feb 5 to 19 | Mar 26 to Apr 9 | Aug 5 to Sep 9 |
| Cilantro | Feb 19 to Mar 5 | Apr 2 to 9 | — |
| Basil | Mar 5 to 19 | Apr 23 to 30 | — |
| Potatoes | — | Mar 26 to Apr 2 | Jul 15 to 22 |
| Garlic | — | Feb 19 to Mar 5 | Nov 4 to 18 |
| Onions | Dec 11 to Jan 22 | Mar 5 to 19 | — |
| Cucumbers | Mar 26 to Apr 9 | Apr 23 to May 7 | Aug 5 to 19 |
| Pumpkins | Mar 26 to Apr 9 | Apr 23 to May 7 | — |
| Peppers | Feb 5 to Mar 5 | Apr 23 to May 7 | Jul 15 to Aug 12 |
| Carrots | — | Mar 12 to Apr 2 | Aug 12 to Sep 2 |
| Sweet Potatoes | — | May 9 to 16 | — |
| Watermelons | Mar 19 to Apr 2 | Apr 23 to May 7 | — |
| Sweet Corn | — | Apr 2 to 16 | Jul 29 to Aug 12 |
| Green Beans | — | Apr 23 to May 7 | Aug 12 to 19 |
| Zucchini | Mar 26 to Apr 9 | Apr 23 to May 7 | Aug 12 to 26 |
| Broccoli | Jan 15 to Feb 5 | Mar 5 to 19 | Aug 19 to Sep 16 |
| Peas | — | Feb 19 to Mar 5 | Aug 12 to 26 |
| Spinach | Feb 19 to 26 | Mar 26 to Apr 9 | Aug 26 to Sep 30 |
| Sunflowers | — | Apr 2 to 23 | — |
| Zinnias | Apr 26 to May 3 | May 24 to Jun 7 | — |
| Tulips | — | — | Sep 23 to Nov 18 |
| Daffodils | — | — | Sep 23 to Nov 4 |
| Grass Seed | — | Feb 19 to Mar 5 | Sep 23 to Oct 7 |
Nearby cities
- St. Peters, MO zone 6b, last frost Apr 8
- Florissant, MO zone 7a, last frost Apr 2
- O'Fallon, MO zone 6b, last frost Apr 10
- St. Louis, MO zone 7a, last frost Apr 8
- Springfield, IL zone 6a, last frost Apr 14
- Columbia, MO zone 6b, last frost Apr 5
Planting in MissouriAbout zone 6bPrintable calendar for St. Charles
Questions
When is the last frost in St. Charles?
Around April 2 in a typical year, based on NOAA's 1991-2020 records for St Louis Lambert International Airport. There is still a 1 in 10 chance of frost after April 17.
What planting zone is St. Charles in?
USDA hardiness zone 6b (2023 map), with parts of the city in zone 7a. The zone tells you which perennials survive the winter; planting dates depend on frost dates instead.
When should I plant tomatoes in St. Charles?
Start seeds indoors February 26 to March 12 and set plants out April 23 to May 7.
When is the first frost in St. Charles?
Around November 4 in a typical year, and before October 23 about 1 year in 10.