Harrison, South Dakota, sits in USDA hardiness zone 5a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
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 Harrison, 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 Harrison 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 Harrison — soil, climate, flood, and parcel records. How we handle your address.
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Harrison — the short answer
Harrison, South Dakota: USDA zone 5a, about 179 days between hard freezes, across 69 acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~179
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 69 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 Harrison's average, not your lot's — a low corner or a tree line moves it. Against Harrison's 179-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Harrison
Each reading below is measured for Harrison itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHarrison runs about 179 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
MeasuredHarrison 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 Harrison is in
Harrison sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Harrison's own centroid rather than borrowed from Douglas County.
What Grows in Harrison
Every plant below cleared Harrison's own zone 5a and its 179-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Harrison?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 24; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 21 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Harrison
Closest first, within ~10 miles of Harrison. Listing isn't leaking, and distance isn't exposure.
- 99N65W 3ABBBNitrate · 2400 ft
- 100N65W24CCCBNitrate · 2.7 mi
- 99N64W 6ABBBNitrate · 3.4 mi
- 99N65W13DDCC2Nitrate · 4.1 mi
- 100N65W 8DAADNitrate · 4.3 mi
- FORMER SPAANS TRUCKINGUnderground Storage Tanks · 5.8 mi
- HOFFMAN GAS & GRILL OF CORSICAUnderground Storage Tanks · 5.8 mi
- DAKOTA MFG CO INCToxics Release Inventory · 5.9 mi
- CORSICA MINI MART, INC.Underground Storage Tanks · 5.9 mi
- ALANS PAINT & BODY INCORPORATEDBrownfields · 5.9 mi
- CHS FARMERS ALLIANCEUnderground Storage Tanks · 5.9 mi
- CHS FARMERS ALLIANCE - CORSICA FEEDToxics Release Inventory · 6.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Harrison'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 Harrison.
Total Sites
57
within ~10 miles of Harrison
Risk Level
Moderate
Highest-severity
2 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Harrison
Severity Distribution
within ~10 miles of Harrison
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Harrison, Nitrate runs higher than the national average — 44 sites within ~10 miles of Harrison. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Harrison
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 Harrison average
Your land is one point inside Harrison
Everything above resolves to Harrison as a whole — one PHZM band and one 28°F frost record, read across 69 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 Harrison Average
Harrison Average
- ●USDA Zones 5a, averaged across Harrison
- ●One soil character for all of Harrison
- ●Frost dates read at Harrison's scale: Apr 21 to Oct 17
YOUR Parcel
- ✓Your exact zone, not Harrison's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Harrison
Pull a site-specific report for your exact address in Harrison, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Harrison averages can't show:
We read public map data around Harrison — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Harrison average
How we know this about Harrison
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 Harrison’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 Harrison
When does frost risk typically end in Harrison?
The last hard freeze (28°F) in Harrison typically lands around Apr 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 May 12.
When is the first frost in Harrison?
The first hard freeze (28°F) in Harrison typically arrives around Oct 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 3, so the watching starts about Sep 17 — about 179 days after the spring freeze cleared.
How long is the growing season in Harrison?
Measured between 28°F hard freezes, Harrison sees about 179 frost-free days — roughly Apr 21 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 12 to Oct 3, about 144 days.
Is the soil safe to grow vegetables in Harrison?
The federal record around Harrison shows 57 documented sites, mostly Nitrate entries (44), the nearest Nitrate record about 0.5 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Harrison?
From about Sep 17 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Harrison's scale — its 5a band and its 179-day season. Your yard writes its own version of Harrison'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 Harrison’s own scale
6 of the readings below were taken at Harrison's own scale — its own ~179-day season between 28°F freezes, the 69 acres it covers and 57 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Harrison's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Harrison's own 28°F hard-freeze dates, about Apr 21 and Oct 17 and the ~179-day span between themNOAA 1991–2020 Climate Normals
- 57 documented contamination sites on the federal record near Harrison, the closest Nitrate record about 0.5 miles out from the town centreFederal environmental registers
- Harrison's boundary and the 69 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~179-day seasonGrowable Ground crop-matching engine
- The ecoregion at Harrison's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Harrison's 69 acres read through its county's SSURGO summaryfrom Douglas County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Douglas County
- The growing challenges every South Dakota grower plans around — written at state scale, so they stay on the state guidefrom South Dakota
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Douglas County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Harrison's 69 acreswhy one lot differs from the next →
- Which side of Harrison you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 69 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate 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 Harrison-wide figureread your own land →
More in South Dakota
Wider growing context
What grows across South DakotaHarrison sits outside our named growing regions, so South Dakota as a whole is its closest context here.
Nearby growing guides