St. Louis city, in Missouri, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Expect cabbage, hazelnut, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
St. Louis city lies within St. Louis Metro — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
St. Louis city holds more than one microclimate.
Soils and elevations shift across St. Louis city, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around St. Louis city — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
St. Louis city — the short answer
St. Louis city, Missouri: USDA zone 7a, about 237 days between hard freezes, across 39K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 21
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 13
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~237
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 39K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 7a is St. Louis city's average, not your lot's — a low corner or a tree line moves it. Against St. Louis city's 237-day season, see what your own ground reads.
Heat in St. Louis city
Across a year, St. Louis city accumulates about 4,158 growing degree days above 50°F, about 405 more than the middle Missouri county — ahead of 105 of Missouri’s 115 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in St. Louis County
Detailed USDA soil-survey (SSURGO) mapping is limited across St. Louis County, so there isn't a reliable county-wide soil summary to show here yet — a gap in the national survey, not in the ground itself.
Soil still varies lot by lot — soil types explained.
What this means for growing in St. Louis city
Each reading below is measured for St. Louis city itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSt. Louis city runs about 237 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredSt. Louis city sits in USDA hardiness zone 7a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country St. Louis city is in
St. Louis city sits in the Interior River Valleys and Hills — EPA Level III, inside the wider Eastern Temperate Forests. One consistent ecological setting across the whole county.
What Grows in St. Louis city
We scored all 1,086 plants against St. Louis city's own USDA zone 7a and its own 237-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Missouri profile.
Is it too late to plant in St. Louis city?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Feb 21; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 21 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 13 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
Documented around St. Louis city
Survey cells within 31 miles of St. Louis city checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 241 miles off. What to watch for.
Safe to Grow Here?
What the federal record shows across St. Louis County — and how to grow with it.
We checked the federal record across St. Louis County — 1,929 documented sites across 7 of the 9 source types we track.
The most significant on record: 27 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across St. Louis County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near St. Louis city
Closest first, across St. Louis County. Listing isn't leaking, and distance isn't exposure.
- GATEWAY OUTDOOR ADVERTISINGUnderground Storage Tanks · 250 ft
- LACLEDE GAS COMPANY - CENTRAL DISTRUnderground Storage Tanks · 300 ft
- UNITED BUMPER INC-UNITED BUMPER INCToxics Release Inventory · 300 ft
- THE SALVATION ARMYUnderground Storage Tanks · 400 ft
- ORION GENOMICS LLCBrownfields · 450 ft
- KEREOS INCBrownfields · 450 ft
- BOARD OF POLICE COMMISIONERSBrownfields · 550 ft
- FLEET SERVICE DIVISIONUnderground Storage Tanks · 600 ft
- LACLEDE GARAGEUnderground Storage Tanks · 600 ft
- KIRBERG ROOFINGUnderground Storage Tanks · 650 ft
- AMOCO OIL SS #8512Underground Storage Tanks · 700 ft
- BEVERAGE CONCEPTSUnderground Storage Tanks · 750 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from St. Louis city's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near St. Louis city.
Total Sites
1,929
across St. Louis County
Risk Level
Elevated
Highest-severity
27 Superfund sites (none NPL-listed)
Sources Checked
across St. Louis County
Severity Distribution
across St. Louis County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around St. Louis city, two things run higher than the national average across St. Louis County — Toxics Release Inventory (165 sites) and Superfund (27 sites). That's not a problem with your land — it's information about it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in St. Louis city
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the St. Louis city average
Your land is one point inside St. Louis city
Everything above resolves to St. Louis city as a whole — one PHZM band and one county frost record, read across 39K acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at county scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better county average.
Your Lot vs the St. Louis city Average
St. Louis city Average
- ●USDA Zones 7a, averaged across St. Louis city
- ●One soil character for all of St. Louis city
- ●Frost dates read at St. Louis city's scale: Mar 21 to Nov 13
YOUR Parcel
- ✓Your exact zone, not St. Louis city's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in St. Louis city
Pull a site-specific report for your exact address in St. Louis city, Missouri — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that St. Louis city averages can't show:
We read public map data around St. Louis city — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the St. Louis city average
How we know this about St. Louis city
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where St. Louis city carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about St. Louis city
When does frost risk typically end in St. Louis city?
The last hard freeze (28°F) in St. Louis city typically lands around Mar 21, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Apr 11.
How long is the growing season in St. Louis city?
Measured between 28°F hard freezes, St. Louis city sees about 237 frost-free days — roughly Mar 21 through Nov 13, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 11 to Oct 30, about 202 days.
Is the soil safe to grow vegetables in St. Louis city?
The federal record around St. Louis city is a meaningful one — 1,929 documented sites, mostly Underground Storage Tanks entries (1,244), the nearest Underground Storage Tanks record under a tenth of a mile out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
Everything above is measured at St. Louis city's scale — its 7a band and its 237-day season. Your yard writes its own version of St. Louis city's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Missouri's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at St. Louis city’s own scale
6 of the readings below were taken at St. Louis city's own scale — its own ~237-day span between 28°F freezes and 1,929 documented sites inside its boundary; 2 are borrowed from a wider read, named and linked below.
Measured here
- St. Louis city's own USDA hardiness band, zones 7aUSDA PHZM 2023
- St. Louis city's own 28°F hard-freeze dates and its ~237-day span between themNOAA 1991–2020 Climate Normals
- 1,929 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record under a tenth of a mile outFederal environmental registers
- St. Louis city's boundary and the 39,499 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~237-day seasonGrowable Ground crop-matching engine
- St. Louis city sitting wholly inside the Interior River Valleys and HillsUS EPA Level III Ecoregions
Inherited from a wider read
What this page can’t tell you
- How the season shifts across St. Louis city — the ~237 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among St. Louis city's 39,499 acreswhy one lot differs from the next →
- Which of those 1,929 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over St. Louis cityread your own land →