Timonium, Maryland, sits in USDA hardiness zone 7b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include cabbage, prickly pear, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Timonium, 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 Timonium 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 Timonium — soil, climate, flood, and parcel records. How we handle your address.
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Timonium — the short answer
Timonium, Maryland: USDA zone 7b, about 245 days between hard freezes, across 4K acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~245
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 4K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 7b is Timonium's average, not your lot's — a low corner or a tree line moves it. Against Timonium's 245-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Timonium
Each reading below is measured for Timonium itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredTimonium runs about 245 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
MeasuredTimonium sits in USDA hardiness zone 7b.
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 Timonium is in
Timonium sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Timonium's own centroid rather than borrowed from Baltimore County.
What Grows in Timonium
Every plant below cleared Timonium's own zone 7b and its 245-day season. Each card opens that plant's Maryland profile. How we score.
Is it too late to plant in Timonium?
Almost never — the real question is what to plant next. 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 21 — 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 Timonium
Spotted lanternfly documented 1 miles from Timonium, first recorded 2022. What to watch for.
What's on the federal record near Timonium
Closest first, within ~10 miles of Timonium. Listing isn't leaking, and distance isn't exposure.
- Stella Maris Operating CorporationUnderground Storage Tanks · 0.5 mi
- BALTIMORE CO. - POLICE PISTOL RANGEBrownfields · 0.7 mi
- POT SPRING ELEMBrownfields · 0.9 mi
- St. Vincent'sUnderground Storage Tanks · 1.0 mi
- Baltimore County Padonia Radio TowerUnderground Storage Tanks · 1.1 mi
- Dulaney Valley Memorial GardensUnderground Storage Tanks · 1.1 mi
- Francis X. Gallagher ServicesUnderground Storage Tanks · 1.2 mi
- Timonium BPUnderground Storage Tanks · 1.2 mi
- BETTY BRITE CLEANERSBrownfields · 1.3 mi
- PADONIA CLEANERSBrownfields · 1.3 mi
- Jiffy Lube Store #687Underground Storage Tanks · 1.4 mi
- TAYLOR RENTALBrownfields · 1.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Timonium'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 Timonium.
Total Sites
2,595
within ~10 miles of Timonium
Risk Level
Elevated
Highest-severity
18 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Timonium
Severity Distribution
within ~10 miles of Timonium
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.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Timonium
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 Timonium average
Your land is one point inside Timonium
Everything above resolves to Timonium as a whole — one PHZM band and one 28°F frost record, read across 4K 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 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 Timonium Average
Timonium Average
- ●USDA Zones 7b, averaged across Timonium
- ●One soil character for all of Timonium
- ●Frost dates read at Timonium's scale: Mar 21 to Nov 21
YOUR Parcel
- ✓Your exact zone, not Timonium's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Timonium
Pull a site-specific report for your exact address in Timonium, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Timonium averages can't show:
We read public map data around Timonium — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Timonium average
How we know this about Timonium
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 Timonium’s own record; 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 Timonium
When does frost risk typically end in Timonium?
The last hard freeze (28°F) in Timonium 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.
When is the first frost in Timonium?
The first hard freeze (28°F) in Timonium typically arrives around Nov 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 7, so the watching starts about Oct 22 — about 245 days after the spring freeze cleared.
How long is the growing season in Timonium?
Measured between 28°F hard freezes, Timonium sees about 245 frost-free days — roughly Mar 21 through Nov 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 11 to Nov 7, about 210 days.
Is the soil safe to grow vegetables in Timonium?
The federal record around Timonium is a meaningful one — 2,595 documented sites, mostly Underground Storage Tanks entries (1,230), the nearest Underground Storage Tanks record about 0.5 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 Timonium?
From about Oct 22 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 21 (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 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Timonium's scale — its 7b band and its 245-day season. Your yard writes its own version of Timonium'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 Timonium’s own scale
7 of the readings below were taken at Timonium's own scale — its own ~245-day season between 28°F freezes, the 3,661 acres it covers and 2,595 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Timonium's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Timonium's own 28°F hard-freeze dates, about Mar 21 and Nov 21 and the ~245-day span between themNOAA 1991–2020 Climate Normals
- 2,595 documented contamination sites on the federal record near Timonium, the closest Underground Storage Tanks record about 0.5 miles out from the town centreFederal environmental registers
- Timonium's boundary and the 3,661 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~245-day seasonGrowable Ground crop-matching engine
- The ecoregion at Timonium's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Timoniumlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Timonium's 3,661 acres read through its county's SSURGO summaryfrom Baltimore County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Baltimore County
- The growing challenges every Maryland grower plans around — written at state scale, so they stay on the state guidefrom Maryland
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Baltimore County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Timonium's 3,661 acreswhy one lot differs from the next →
- Which side of Timonium you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,661 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.5 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 Timonium-wide figureread your own land →
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