When to plant in Ballwin, MO
USDA Zone 7aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Ballwin, Missouri — all computed from Ballwin's nearest NOAA weather station.
Zone 7a means many perennials and even some tender shrubs overwinter in Ballwin, while your frost dates still decide when annuals go out.
Frost probability
ST CHARLES 7 SSW · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Ballwin’s own odds, recorded at ST CHARLES 7 SSW.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 1 | Apr 16 | Apr 3 | Oct 5 | Oct 19 | Oct 31 |
| 32°F | Apr 21 | Apr 4 | Mar 20 | Oct 15 | Oct 29 | Nov 11 |
| 28°F | Apr 8 | Mar 25 | Mar 8 | Oct 27 | Nov 8 | Nov 27 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Ballwin, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 16 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Ballwin planting FAQ
When is the last spring frost in Ballwin, MO?
Ballwin's average last spring frost falls near April 4 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Ballwin, MO?
Expect Ballwin's first fall frost near October 29 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Ballwin in?
Ballwin is in USDA hardiness zone 7a. In zone 7a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Ballwin?
There are roughly 208 frost-free days in Ballwin (a moderate growing season), running from the average last frost around April 4 to the first fall frost near October 29.
When should I plant tomatoes in Ballwin?
In Ballwin, start tomato seeds indoors around February 7–February 21, then transplant seedlings outdoors around April 11 once the danger of frost has passed.
Never miss a window in Ballwin
An email when it’s time to start seeds, transplant, and sow — timed to Ballwin’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Ellisville · 3 km
- Manchester · 4 km
- Chesterfield · 7 km
- Town and Country · 7 km
- Wildwood · 10 km
- Kirkwood · 11 km
- Creve Coeur · 12 km
- Eureka · 14 km
Frost dates recorded at ST CHARLES 7 SSW, 10 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Ballwin, MO — Frost Dates & Zone 7a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00237398. Retrieved from https://blissgarden.com/missouri/ballwin.