Irmo, South Carolina, sits in USDA hardiness zone 8b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
On paper, cabbage, fig, california poppy, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Irmo, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Irmo lot. 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 Irmo — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Irmo — the short answer
Irmo, South Carolina: USDA zone 8b, about 272 days between hard freezes, across 4K acres of town.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 3
- Richland County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Nov 30
- Richland County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~272
- Richland County normal — NOAA 1991–2020, nearest to this town
- Town area
- 4K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Richland County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 8b is Irmo's average, not your lot's — a low corner or a tree line moves it. Against Irmo's 272-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Irmo
Each reading below is measured for Irmo itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsIrmo runs about 272 days between hard freezes (read from Richland County, the closest normal to Irmo) — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredIrmo sits in USDA hardiness zone 8b.
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 Irmo is in
Irmo sits in the Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Irmo's own centroid, and it is not what its county reads: Richland County is mostly Southeastern Plains. The wider page above you is answering a different question about different ground.
What Grows in Irmo
Every plant below cleared Irmo's own zone 8b and its 272-day season. Each card opens that plant's South Carolina profile. How we score.
Is it too late to plant in Irmo?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 3; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 3 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 30 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
Documented around Irmo
Survey cells within 31 miles of Irmo checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 99 miles off. What to watch for.
What's on the federal record near Irmo
Closest first, within ~10 miles of Irmo. Listing isn't leaking, and distance isn't exposure.
- SPINX 265Underground Storage Tanks · 2400 ft
- FRIARSGATE SUPERMARTUnderground Storage Tanks · 0.5 mi
- SPORT PAGEUnderground Storage Tanks · 0.7 mi
- SHENANDOAH RESTORATIONS INCBrownfields · 0.9 mi
- CIRCLE K 2720323Underground Storage Tanks · 0.9 mi
- KRM MIDLANDS, LLC-PLANT 7Toxics Release Inventory · 0.9 mi
- HARDAWAY CONCRETE CO INC PLT 10Underground Storage Tanks · 0.9 mi
- KNIGHT'S REDI-MIX, IRMO PLANTToxics Release Inventory · 0.9 mi
- IRMO BODY SHOPBrownfields · 0.9 mi
- IRMO TIRE & AUTOUnderground Storage Tanks · 0.9 mi
- IMPORTS PLUSBrownfields · 0.9 mi
- PLAYERS LOUNGEUnderground Storage Tanks · 1.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Irmo'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 Irmo.
Total Sites
708
within ~10 miles of Irmo
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Irmo
Severity Distribution
within ~10 miles of Irmo
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •TRI facilities report what they release. Check the wind — downwind beds catch more of it.
Check your specific parcel in Irmo
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 Irmo average
Your land is one point inside Irmo
Everything above resolves to Irmo as a whole — one PHZM band, read across 4K acres, with hard-freeze dates borrowed from Richland County’s record because no 30-year normal resolves at this town’s own centroid. 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 town 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 local average.
Your Lot vs the Irmo Average
Irmo Average
- ●USDA Zones 8b, averaged across Irmo
- ●One soil character for all of Irmo
- ●Frost dates read at Irmo's scale: Mar 3 to Nov 30
YOUR Parcel
- ✓Your exact zone, not Irmo's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Irmo
Pull a site-specific report for your exact address in Irmo, South Carolina — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Irmo averages can't show:
We read public map data around Irmo — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Irmo average
How we know this about Irmo
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Richland County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Irmo
When does frost risk typically end in Irmo?
The last hard freeze (28°F) in Irmo typically lands around Mar 3, 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 Mar 24.
When is the first frost in Irmo?
The first hard freeze (28°F) in Irmo typically arrives around Nov 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 16, so the watching starts about Oct 31 — about 272 days after the spring freeze cleared.
How long is the growing season in Irmo?
Measured between 28°F hard freezes, Irmo sees about 272 frost-free days — roughly Mar 3 through Nov 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 24 to Nov 16, about 237 days.
Is the soil safe to grow vegetables in Irmo?
The federal record around Irmo is a meaningful one — 708 documented sites, mostly Underground Storage Tanks entries (408), the nearest Underground Storage Tanks record about 0.4 miles 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.
How do I protect my plants from frost in Irmo?
From about Oct 31 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Nov 30 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Nov 30. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Irmo's scale — its 8b band and its 272-day season. Your yard writes its own version of Irmo's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Irmo’s own scale
6 of the readings below were taken at Irmo's own scale — the 4,369 acres it covers and 708 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Irmo's own USDA hardiness band, zones 8bUSDA PHZM 2023
- 708 documented contamination sites on the federal record near Irmo, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Irmo's boundary and the 4,369 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~272-day seasonGrowable Ground crop-matching engine
- Irmo sits in the Piedmont — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- Lanternfly survey cells around Irmo checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- The 28°F hard-freeze dates — Irmo has no normal of its own, so its county's is the closest measured readfrom Richland County
- Soil character — no town-scale survey exists, so Irmo's 4,369 acres read through its county's SSURGO summaryfrom Richland County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Richland County
- The growing challenges every South Carolina grower plans around — written at state scale, so they stay on the state guidefrom South Carolina
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Richland County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Irmo's 4,369 acreswhy one lot differs from the next →
- Which side of Irmo you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,369 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Irmo-wide figureread your own land →