USDA hardiness zone lookup
Saint Charles, MO — USDA Zone 6b
Saint Charles, Missouri · 184-day growing season
Frost dates and growing season in Saint Charles
| USDA hardiness zone | Zone 6b |
|---|---|
| Average last spring frost | April 16 |
| Average first fall frost | October 17 |
| Growing season length | ~184 days |
| Temperature range (F) | -10 to 0°F |
| Temperature range (C) | -23 to -18°C |
All of Saint Charles's mapped ZIP codes fall in the same hardiness band, Zone 6b.
These are 50%-probability averages modeled from Saint Charles's USDA hardiness zone and regional climate normals — not a single-station reading. In a typical year the last spring frost will have passed by April 16, but a colder-than-average year can run 1-2 weeks later. Plant tender crops (tomatoes, peppers, basil) once both soil and night temperatures are consistently warm — a thermometer beats the calendar.
Growing season in Saint Charles
Saint Charles, Missouri sits in USDA Zone 6b, with roughly 184 frost-free days between an average last spring frost around April 16 and a first fall frost around October 17. That is a long season — succession-sow through summer and run a full fall crop; heat-sensitive greens still need spring/autumn timing.
What grows in Saint Charles
Saint Charles falls in USDA Zone 6b, so the same hardiness constraints apply as the full Zone 6 guide. Vegetables, herbs, and fruit trees rated to Zone 6b (or hardier) will overwinter here in a typical year.
- Tomatoes (all types)
- Peppers, eggplant
- Squash, melons, cucumbers
- Beans, peas
- Sweet corn
- Apples, pears, peaches, plums
- Cherries, blueberries
- Asparagus, rhubarb
- Garlic (fall-planted)
- Strawberries
What to plant in Saint Charles this week
Saint Charles is in high summer — most spring plantings are in. Keep an eye on watering and start planning your fall crop. Cool-season seedlings (broccoli, cabbage, lettuce) can be started indoors for a fall transplant.
- When to plant tomatoes in zone 6
- When to plant peppers in zone 6
- When to plant bush beans in zone 6
- When to plant cucumbers in zone 6
- When to plant basil in zone 6
Full planting calendar for Saint Charles
Crop-by-crop sowing, transplant, and harvest dates calibrated to zone 6 averages:
- When to plant tomatoes in zone 6
- When to plant peppers in zone 6
- When to plant basil in zone 6
- When to plant garlic in zone 6
- When to plant lettuce in zone 6
- When to plant bush beans in zone 6
- When to plant cucumbers in zone 6
- When to plant summer squash in zone 6
- When to plant peas in zone 6
- When to plant carrots in zone 6
ZIP codes in Saint Charles
Drill down to the precise frost window and planting calendar for a specific ZIP in Saint Charles:
Local microclimate notes
Zone tables give you the average — but Saint Charlesgardens vary. South-facing walls and paved areas can run a full half-zone warmer than the published rating. Low-lying spots, frost pockets, and shaded north sides can run colder. If you've gardened here a few seasons, your own frost record — the last time you actually got frost damage — beats any national average.
Source and methodology
Hardiness zone from the USDA Plant Hardiness Zone Map (2023 revision). Frost-date and growing-season figures are modeled from Saint Charles's USDA hardiness zone and regional NOAA 1991-2020 climate normals — zone-level estimates, not a per-station record, so treat them as planning guidance and confirm against your own local frost history. Crop recommendations draw on US Cooperative Extension references, curated by the Growli editorial team. Last reviewed June 2026.
Other cities in Missouri
- Columbia, MO — USDA Zone 6b
- Jefferson City, MO — USDA Zone 6b
- Joplin, MO — USDA Zone 7a
- Kansas City, MO — USDA Zone 6b
- Lake Saint Louis, MO — USDA Zone 6b
- Saint Joseph, MO — USDA Zone 6a
- Saint Louis, MO — USDA Zone 7a
- Springfield, MO — USDA Zone 7a
- All of Missouri by zone