Round Top, Texas, sits in USDA hardiness zone 9a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with artichoke, fig, california poppy, and cabbage — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Round Top, 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 Round Top 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 Round Top — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Round Top — the short answer
Round Top, Texas: USDA zone 9a, about 304 days between hard freezes, across 611 acres of town.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 7
- Fayette County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 8
- Fayette County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~304
- Fayette County normal — NOAA 1991–2020, nearest to this town
- Town area
- 611 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 Fayette County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9a is Round Top's average, not your lot's — a low corner or a tree line moves it. Against Round Top's 304-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Round Top
Each reading below is measured for Round Top itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsRound Top runs about 304 days between hard freezes (read from Fayette County, the closest normal to Round Top) — 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
MeasuredRound Top sits in USDA hardiness zone 9a.
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 Round Top is in
Round Top sits in the Texas Blackland Prairies — EPA Level III, inside the wider Great Plains. That is read at Round Top's own centroid rather than borrowed from Fayette County.
What Grows in Round Top
Every plant below cleared Round Top's own zone 9a and its 304-day season. Each card opens that plant's Texas profile. How we score.
Is it too late to plant in Round Top?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Jan 10; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 8 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
What's on the federal record near Round Top
Closest first, within ~10 miles of Round Top. Listing isn't leaking, and distance isn't exposure.
- ROUND TOP SERVICE STATIONUnderground Storage Tanks · 750 ft
- ROUND TOP MERCANTILEUnderground Storage Tanks · 1800 ft
- FAYETTE COUNTY PCT 2 WAREHOUSEUnderground Storage Tanks · 2.1 mi
- CORDES CORNERSUnderground Storage Tanks · 3.6 mi
- WARRENTON GROCERY STOREUnderground Storage Tanks · 3.8 mi
- YY-59-59-303Nitrate · 4.6 mi
- YY-59-60-105Nitrate · 5.6 mi
- JACOBS STOREUnderground Storage Tanks · 5.8 mi
- JACOB BROTHERS RANCHUnderground Storage Tanks · 5.9 mi
- THE VILLAGE MARKETUnderground Storage Tanks · 5.9 mi
- CARMINE TRAVEL CENTERUnderground Storage Tanks · 5.9 mi
- YY-59-60-103Nitrate · 5.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Round Top'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 Round Top.
Total Sites
38
within ~10 miles of Round Top
Risk Level
Low
Highest-severity
1 concentrated animal feeding operation
Sources Checked
within ~10 miles of Round Top
Severity Distribution
within ~10 miles of Round Top
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Round Top, Nitrate runs higher than the national average — 24 sites within ~10 miles of Round Top. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Round Top
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 Round Top average
Your land is one point inside Round Top
Everything above resolves to Round Top as a whole — one PHZM band, read across 611 acres, with hard-freeze dates borrowed from Fayette 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 Round Top Average
Round Top Average
- ●USDA Zones 9a, averaged across Round Top
- ●One soil character for all of Round Top
- ●Frost dates read at Round Top's scale: Feb 7 to Dec 8
YOUR Parcel
- ✓Your exact zone, not Round Top's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Round Top
Pull a site-specific report for your exact address in Round Top, Texas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Round Top averages can't show:
We read public map data around Round Top — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Round Top average
How we know this about Round Top
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 Fayette 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 Round Top
When does frost risk typically end in Round Top?
The last hard freeze (28°F) in Round Top typically lands around Feb 7, 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 Feb 28.
When is the first frost in Round Top?
The first hard freeze (28°F) in Round Top typically arrives around Dec 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 24, so the watching starts about Nov 8 — about 304 days after the spring freeze cleared.
How long is the growing season in Round Top?
Measured between 28°F hard freezes, Round Top sees about 304 frost-free days — roughly Feb 7 through Dec 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 28 to Nov 24, about 269 days.
Is the soil safe to grow vegetables in Round Top?
The federal record around Round Top is light — 38 documented sites across the 9 federal source types we checked, mostly Nitrate entries (24), the nearest Underground Storage Tanks record about 0.1 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Round Top?
From about Nov 8 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 Dec 8 (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 Dec 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Round Top's scale — its 9a band and its 304-day season. Your yard writes its own version of Round Top'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 Round Top’s own scale
5 of the readings below were taken at Round Top's own scale — the 611 acres it covers and 38 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Round Top's own USDA hardiness band, zones 9aUSDA PHZM 2023
- 38 documented contamination sites on the federal record near Round Top, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Round Top's boundary and the 611 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~304-day seasonGrowable Ground crop-matching engine
- The ecoregion at Round Top's own centroid, the Texas Blackland PrairiesUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Round Top has no normal of its own, so its county's is the closest measured readfrom Fayette County
- Soil character — no town-scale survey exists, so Round Top's 611 acres read through its county's SSURGO summaryfrom Fayette County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Fayette County
- The growing challenges every Texas grower plans around — written at state scale, so they stay on the state guidefrom Texas
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Fayette County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Round Top's 611 acreswhy one lot differs from the next →
- Which side of Round Top you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 611 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Round Top-wide figureread your own land →
More in Texas
Wider growing context
What grows across TexasRound Top sits outside our named growing regions, so Texas as a whole is its closest context here.
Nearby growing guides