Monrovia, Maryland, sits in USDA hardiness zone 7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
The conditions favor cabbage, hazelnut, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Monrovia, 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 Monrovia 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 Monrovia — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Monrovia — the short answer
Monrovia, Maryland: USDA zone 7a, about 223 days between hard freezes, across 1K acres of town.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~223
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 7a is Monrovia's average, not your lot's — a low corner or a tree line moves it. Against Monrovia's 223-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Monrovia
Each reading below is measured for Monrovia itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMonrovia runs about 223 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
MeasuredMonrovia 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 Monrovia is in
Monrovia sits in the Northern Piedmont — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Monrovia's own centroid rather than borrowed from Frederick County.
What Grows in Monrovia
Every plant below cleared Monrovia's own zone 7a and its 223-day season. Each card opens that plant's Maryland profile. How we score.
Is it too late to plant in Monrovia?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 8 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
Documented around Monrovia
Spotted lanternfly documented 1 miles from Monrovia, first recorded 2022. What to watch for.
What's on the federal record near Monrovia
Closest first, within ~10 miles of Monrovia. Listing isn't leaking, and distance isn't exposure.
- Monrovia Main Post OfficeUnderground Storage Tanks · 2000 ft
- MDOT SHA BRIDGE # 1015600Brownfields · 2500 ft
- PROSTART PERFORMANCEBrownfields · 0.6 mi
- MD2200 (AT&T)Underground Storage Tanks · 0.9 mi
- COSTCO WHOLESALE E-COMMERCE/RETURNS CENTER #731/1996Brownfields · 1.1 mi
- FR Ef 11Nitrate · 1.2 mi
- Green Valley GarageUnderground Storage Tanks · 1.3 mi
- FR Ef 56Nitrate · 1.3 mi
- Green Valley Convenience StoreUnderground Storage Tanks · 1.4 mi
- Green Valley BPUnderground Storage Tanks · 1.5 mi
- Hahn Transportation, Inc.Underground Storage Tanks · 1.6 mi
- FR Ef 52Nitrate · 1.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Monrovia'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 Monrovia.
Total Sites
860
within ~10 miles of Monrovia
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Monrovia
Severity Distribution
within ~10 miles of Monrovia
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 Monrovia
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 Monrovia average
Your land is one point inside Monrovia
Everything above resolves to Monrovia as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Monrovia Average
Monrovia Average
- ●USDA Zones 7a, averaged across Monrovia
- ●One soil character for all of Monrovia
- ●Frost dates read at Monrovia's scale: Mar 30 to Nov 8
YOUR Parcel
- ✓Your exact zone, not Monrovia's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Monrovia
Pull a site-specific report for your exact address in Monrovia, Maryland — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Monrovia averages can't show:
We read public map data around Monrovia — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Monrovia average
How we know this about Monrovia
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 Monrovia’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 Monrovia
When does frost risk typically end in Monrovia?
The last hard freeze (28°F) in Monrovia typically lands around Mar 30, 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 20.
When is the first frost in Monrovia?
The first hard freeze (28°F) in Monrovia typically arrives around Nov 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 25, so the watching starts about Oct 9 — about 223 days after the spring freeze cleared.
How long is the growing season in Monrovia?
Measured between 28°F hard freezes, Monrovia sees about 223 frost-free days — roughly Mar 30 through Nov 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 20 to Oct 25, about 188 days.
Is the soil safe to grow vegetables in Monrovia?
The federal record around Monrovia is a meaningful one — 860 documented sites, mostly Underground Storage Tanks entries (395), 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 Monrovia?
From about Oct 9 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 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 Nov 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Monrovia's scale — its 7a band and its 223-day season. Your yard writes its own version of Monrovia'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 Monrovia’s own scale
7 of the readings below were taken at Monrovia's own scale — its own ~223-day season between 28°F freezes, the 1,437 acres it covers and 860 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Monrovia's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Monrovia's own 28°F hard-freeze dates, about Mar 30 and Nov 8 and the ~223-day span between themNOAA 1991–2020 Climate Normals
- 860 documented contamination sites on the federal record near Monrovia, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Monrovia's boundary and the 1,437 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~223-day seasonGrowable Ground crop-matching engine
- The ecoregion at Monrovia's own centroid, the Northern PiedmontUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Monrovialydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Monrovia's 1,437 acres read through its county's SSURGO summaryfrom Frederick County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Frederick 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 Frederick County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Monrovia's 1,437 acreswhy one lot differs from the next →
- Which side of Monrovia you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,437 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 Monrovia-wide figureread your own land →
More in Maryland
Growing region
Nearby growing guides