Mahtomedi, Minnesota, sits in USDA hardiness zone 5a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Expect cabbage, cranberry, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Mahtomedi, 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 Mahtomedi 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 Mahtomedi — soil, climate, flood, and parcel records. How we handle your address.
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Mahtomedi — the short answer
Mahtomedi, Minnesota: USDA zone 5a, about 193 days between hard freezes, across 2K acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~193
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 5a is Mahtomedi's average, not your lot's — a low corner or a tree line moves it. Against Mahtomedi's 193-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mahtomedi
Each reading below is measured for Mahtomedi itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMahtomedi runs about 193 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredMahtomedi sits in USDA hardiness zone 5a.
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 Mahtomedi is in
Mahtomedi sits in the North Central Hardwood Forests — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Mahtomedi's own centroid rather than borrowed from Washington County.
What Grows in Mahtomedi
Every plant below cleared Mahtomedi's own zone 5a and its 193-day season. Each card opens that plant's Minnesota profile. How we score.
Is it too late to plant in Mahtomedi?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 25 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Mahtomedi
Closest first, within ~10 miles of Mahtomedi. Listing isn't leaking, and distance isn't exposure.
- Johnson Boat Works IncUnderground Storage Tanks · 250 ft
- Mahtomedi CashwayUnderground Storage Tanks · 0.6 mi
- EAST SHORE AUTO REPAIRBrownfields · 0.6 mi
- East Shore Auto RepairUnderground Storage Tanks · 0.6 mi
- O'LEARY'S AUTO BODY INCBrownfields · 0.7 mi
- STILLWATER MEDICAL GROUPBrownfields · 0.7 mi
- Skyline CleanersUnderground Storage Tanks · 0.7 mi
- SAINT JUDE OF THE LAKEBrownfields · 0.7 mi
- ENCORE AT MAHTOMEDIBrownfields · 0.7 mi
- MAHTOMEDI PUBLIC WORKS DEPARTMENTBrownfields · 0.8 mi
- MATRIX MARINE INCBrownfields · 0.8 mi
- CAT CARE CLINICBrownfields · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mahtomedi'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 Mahtomedi.
Sources Checked
within ~10 miles of Mahtomedi
Severity Distribution
within ~10 miles of Mahtomedi
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mahtomedi, Brownfields runs higher than the national average — 2,535 sites within ~10 miles of Mahtomedi. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Mahtomedi
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 Mahtomedi average
Your land is one point inside Mahtomedi
Everything above resolves to Mahtomedi as a whole — one PHZM band and one 28°F frost record, read across 2K 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 city 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 Mahtomedi Average
Mahtomedi Average
- ●USDA Zones 5a, averaged across Mahtomedi
- ●One soil character for all of Mahtomedi
- ●Frost dates read at Mahtomedi's scale: Apr 15 to Oct 25
YOUR Parcel
- ✓Your exact zone, not Mahtomedi's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mahtomedi
Pull a site-specific report for your exact address in Mahtomedi, Minnesota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mahtomedi averages can't show:
We read public map data around Mahtomedi — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mahtomedi average
How we know this about Mahtomedi
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Mahtomedi’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 city grain anywhere on this page — there is no city-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 Mahtomedi
When does frost risk typically end in Mahtomedi?
The last hard freeze (28°F) in Mahtomedi typically lands around Apr 15, 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 May 6.
When is the first frost in Mahtomedi?
The first hard freeze (28°F) in Mahtomedi typically arrives around Oct 25, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 11, so the watching starts about Sep 25 — about 193 days after the spring freeze cleared.
How long is the growing season in Mahtomedi?
Measured between 28°F hard freezes, Mahtomedi sees about 193 frost-free days — roughly Apr 15 through Oct 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 11, about 158 days.
Is the soil safe to grow vegetables in Mahtomedi?
The federal record around Mahtomedi runs heavier than most — 3,851 documented sites, mostly Brownfields entries (2,535), the nearest Underground Storage Tanks record under a tenth of a mile out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Mahtomedi?
From about Sep 25 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 Oct 25 (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 Oct 25. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mahtomedi's scale — its 5a band and its 193-day season. Your yard writes its own version of Mahtomedi'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 Mahtomedi’s own scale
6 of the readings below were taken at Mahtomedi's own scale — its own ~193-day season between 28°F freezes, the 2,220 acres it covers and 3,851 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Mahtomedi's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Mahtomedi's own 28°F hard-freeze dates, about Apr 15 and Oct 25 and the ~193-day span between themNOAA 1991–2020 Climate Normals
- 3,851 documented contamination sites on the federal record near Mahtomedi, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Mahtomedi's boundary and the 2,220 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~193-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mahtomedi's own centroid, the North Central Hardwood ForestsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Mahtomedi's 2,220 acres read through its county's SSURGO summaryfrom Washington County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Washington County
- The growing challenges every Minnesota grower plans around — written at state scale, so they stay on the state guidefrom Minnesota
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Washington County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mahtomedi's 2,220 acreswhy one lot differs from the next →
- Which side of Mahtomedi you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,220 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Mahtomedi-wide figureread your own land →