Williams County, in North Dakota, sits in USDA hardiness zone 4a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Reliable performers under these conditions include cabbage, cranberry, cilantro, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Williams County lies within the North Dakota Badlands — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Williams County holds more than one microclimate.
Soils and elevations shift across Williams County, so your frost dates and drainage aren't the county average. 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 Williams County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Williams County — the short answer
Williams County, North Dakota: USDA zone 4a, about 148 days between hard freezes, across 1.3M acres.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 6
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 1
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~148
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.3M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 4a is Williams County's average, not your lot's — a low corner or a tree line moves it. Against Williams County's 148-day season, see what your own ground reads.
Heat in Williams County
Across a year, Williams County accumulates about 1,810 growing degree days above 50°F, about 103 fewer than the middle North Dakota county — ahead of 13 of North Dakota’s 53 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Williams County
Across Williams County, the ground is predominantly Mollisols, where Williams, Bowbells, and Zahl are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 7.0–7.2, neutral. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
2%
Hydric soils
5%
Soil still varies lot by lot — soil types explained.
How the ground varies across Williams County
The USDA soil survey maps 84% of Williams County as well drained — but another 12% drains differently: 3% somewhat excessively drained, 3% poorly drained.
Williams is the most extensive named soil at 32% of mapped acres, then Bowbells (13%) and Zahl (9%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Williams County
Each reading below is measured for Williams County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Williams County are well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Williams County runs about pH 7.0–7.2, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredWilliams County runs about 148 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredWilliams County sits in USDA hardiness zone 4a.
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 Williams County is in
Williams County spans 2 EPA Level III ecoregions — Northwestern Glaciated Plains (79%) and Northwestern Great Plains (21%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Williams County
We scored all 1,086 plants against Williams County's own USDA zone 4a and its own 148-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's North Dakota profile.
Is it too late to plant in Williams County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 1 — long-season crops need about 90 days of runway, quick greens only 30. In a season this compact, fast finishers and cold-hardy greens do the late work, and garlic tucked in before the freeze repays you next summer.
What gets applied to farmland in Williams County
USGS estimates 387,927 lb of Glyphosate on Williams County farmland in 2019, its largest by weight, ahead of Bromoxynil (63,880 lb) and 2,4-d (46,360 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Williams County — and how to grow with it.
We checked the federal record across Williams County — 548 documented sites across 6 of the 9 source types we track.
The most significant on record: 3 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Williams County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Williams County
Closest first, across Williams County. Listing isn't leaking, and distance isn't exposure.
- 157-099-21BBBNitrate · 4.1 mi
- 156-100-07CCC2Nitrate · 4.7 mi
- Pilot Travel Center 589Underground Storage Tanks · 5.4 mi
- A T and T CommunicationsUnderground Storage Tanks · 5.5 mi
- 156-100-33CCCNitrate · 5.5 mi
- 155-100-06AAA2Nitrate · 6.2 mi
- 156-098-07CCCNitrate · 7.3 mi
- BLACKTAIL CREEK SPILLSuperfund · 7.4 mi
- 155-099-01BCCNitrate · 8.2 mi
- 156-101-04CDDNitrate · 8.3 mi
- Burlington Northern Railroad CompanyUnderground Storage Tanks · 8.3 mi
- POLAR SERVICE CENTER - WILLISTONBrownfields · 8.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Williams County'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 Williams County.
Total Sites
548
across Williams County
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
across Williams County
Severity Distribution
across Williams County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Williams County, Nitrate runs higher than the national average — 290 sites across Williams County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
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 Williams County
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 Williams County average
Your land is one point inside Williams County
Everything above resolves to Williams County as a whole — one PHZM band and one county frost record, read across 1.3M 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 county 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 county average.
Your Lot vs the Williams County Average
Williams County Average
- ●USDA Zones 4a, averaged across Williams County
- ●One soil character for all of Williams County
- ●Frost dates read at Williams County's scale: May 6 to Oct 1
YOUR Parcel
- ✓Your exact zone, not Williams County's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Williams County
Pull a site-specific report for your exact address in Williams County, North Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Williams County averages can't show:
We read public map data around Williams County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Williams County average
How we know this about Williams County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Williams County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Williams County
When does frost risk typically end in Williams County?
The last hard freeze (28°F) in Williams County typically lands around May 6, 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 27.
How long is the growing season in Williams County?
Measured between 28°F hard freezes, Williams County sees about 148 frost-free days — roughly May 6 through Oct 1, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 27 to Sep 17, about 113 days.
Is the soil safe to grow vegetables in Williams County?
The federal record around Williams County is a meaningful one — 548 documented sites, mostly Nitrate entries (290), the nearest Nitrate record about 4.1 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 gardeners stretch the season in Williams County?
With about 148 frost-free days between hard freezes, Williams County rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 176 to 204 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 6 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Williams County's scale — its 4a band and its 148-day season. Your yard writes its own version of Williams County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads North Dakota's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Williams County’s own scale
8 of the readings below were taken at Williams County's own scale — its own ~148-day span between 28°F freezes, the 3 most extensive soil series mapped here and 548 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Williams County's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Williams County's own 28°F hard-freeze dates and its ~148-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Williams CountyUSDA NRCS SSURGO
- 548 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 4.1 miles outFederal environmental registers
- Williams County's boundary and the 1,329,663 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~148-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Williams County spans, Northwestern Glaciated Plains the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Williams County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every North Dakota grower plans around — written at state scale, so they stay on the state guidefrom North Dakota
What this page can’t tell you
- How the season shifts across Williams County — the ~148 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Williams County's 1,329,663 acreswhy one lot differs from the next →
- Which of those 548 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Williams Countyread your own land →