Allen, South Dakota, sits in USDA hardiness zone 5a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Allen, 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 Allen 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 Allen — soil, climate, flood, and parcel records. How we handle your address.
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Allen — the short answer
Allen, South Dakota: USDA zone 5a, about 161 days between hard freezes, across 2K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 3
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~161
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town 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 Allen's average, not your lot's — a low corner or a tree line moves it. Against Allen's 161-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Allen
Each reading below is measured for Allen itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredAllen runs about 161 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
MeasuredAllen 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 Allen is in
Allen sits in the Northwestern Great Plains — EPA Level III, inside the wider Great Plains. That is read at Allen's own centroid rather than borrowed from Bennett County.
What Grows in Allen
Every plant below cleared Allen's own zone 5a and its 161-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Allen?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 5; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 3 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 11 — 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 Allen
Closest first, within ~10 miles of Allen. Listing isn't leaking, and distance isn't exposure.
- 38N39W10CBNitrate · 500 ft
- ALLEN STOREUnderground Storage Tanks · 900 ft
- AMERICAN HORSE SCHOOLUnderground Storage Tanks · 950 ft
- 39N39W19DDBC (2)Nitrate · 4.5 mi
- 38N38W22CBDCNitrate · 6.3 mi
- 37N39W16DDDDNitrate · 7.3 mi
- 37N39W17DDDDNitrate · 7.4 mi
- 37N39W26AAAANitrate · 8.5 mi
- 37N39W34BBBNitrate · 9.3 mi
- KYLE HEALTH CENTERBrownfields · 9.4 mi
- PINE RIDGE HOSPITALBrownfields · 9.4 mi
- D-4Underground Storage Tanks · 9.6 mi
2 more sites are on the record inside the same radius. See them on the map
Measured from Allen'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 Allen.
Severity Distribution
within ~10 miles of Allen
Highest-Severity Sites
Know Before You Grow
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •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.
Check your specific parcel in Allen
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 Allen average
Your land is one point inside Allen
Everything above resolves to Allen 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 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 Allen Average
Allen Average
- ●USDA Zones 5a, averaged across Allen
- ●One soil character for all of Allen
- ●Frost dates read at Allen's scale: May 3 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Allen's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Allen
Pull a site-specific report for your exact address in Allen, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Allen averages can't show:
We read public map data around Allen — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Allen average
How we know this about Allen
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 Allen’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 Allen
When does frost risk typically end in Allen?
The last hard freeze (28°F) in Allen typically lands around May 3, 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 24.
When is the first frost in Allen?
The first hard freeze (28°F) in Allen typically arrives around Oct 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 27, so the watching starts about Sep 11 — about 161 days after the spring freeze cleared.
How long is the growing season in Allen?
Measured between 28°F hard freezes, Allen sees about 161 frost-free days — roughly May 3 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 24 to Sep 27, about 126 days.
Is the soil safe to grow vegetables in Allen?
The federal record around Allen is light — 22 documented sites across the 9 federal source types we checked, mostly Nitrate entries (16), the nearest Nitrate record under a tenth of a mile 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 Allen?
From about Sep 11 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 11 (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 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Allen's scale — its 5a band and its 161-day season. Your yard writes its own version of Allen'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 Allen’s own scale
6 of the readings below were taken at Allen's own scale — its own ~161-day season between 28°F freezes, the 2,076 acres it covers and 22 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Allen's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Allen's own 28°F hard-freeze dates, about May 3 and Oct 11 and the ~161-day span between themNOAA 1991–2020 Climate Normals
- 22 documented contamination sites on the federal record near Allen, the closest Nitrate record under a tenth of a mile out from the town centreFederal environmental registers
- Allen's boundary and the 2,076 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~161-day seasonGrowable Ground crop-matching engine
- The ecoregion at Allen's own centroid, the Northwestern Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Allen's 2,076 acres read through its county's SSURGO summaryfrom Bennett County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Bennett 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 Bennett County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Allen's 2,076 acreswhy one lot differs from the next →
- Which side of Allen you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,076 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate 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 Allen-wide figureread your own land →
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