mustard greens (Brassica juncea), photographi

Can I Grow Mustard Greens in Wyoming?

USDA Zones 3b-6a · Plant zone range 2-11

Yes — Strong Match

mustard greens is grown in zones 2-11, which covers every zone Wyoming contains (3b-6a). Whether the season is long enough is the question that remains.

Mustard Greens in Wyoming — the short answer

Mustard Greens in Wyoming: grown in zones 2–11, part sun, against a state median of ~151 frost-free days.

Plant zones
2-11
Not verified
Wyoming zones
3b-6a
USDA PHZM 2023
Frost window
May 4 - May 13 – Sep 30 - Oct 7
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
79 days
NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Days to maturity
60 days
Growable Ground Plant Database

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.

Score your parcel · free to start

Your yard isn't the whole zone.

Wyoming spans zones 3b-6a, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score mustard greens against your parcel's actual hardiness, soil, and sun.

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

No card required · your parcel report in seconds — read in full free for your first 14 days

Wyoming is not one climate

A single Wyoming answer averages 23 counties whose growing seasons are 87 days apart — from 79 frost-free days in Teton County to 166 in Big Horn County. Which end of that your land sits nearer changes what mustard greens can finish before the first hard freeze.

79 daysTeton County166 daysBig Horn County

The middle half of 23 counties runs 136–155 days, with a median of 151 days — a 87-day span end to end.

Measured across 23 Wyoming counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.

Where in Wyoming Fits Best

Even within Wyoming's zones 3b-6a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for mustard greens (USDA PHZM 2023):

Zone Comparison

Mustard Greens Needs

  • USDA Zones: 2-11
  • Frost-Free Days: 50+
  • Sun: Part SunWe haven't confirmed this against a published source yet.
  • Mature size: 1.5 ft tallWe haven't confirmed this against a published source yet.
  • Picking window: ~20 days of harvestWe haven't confirmed this against a published source yet.
  • Drought tolerance: Low

Wyoming Has

  • USDA Zones: 3b-6a
  • Last Hard Freeze (28°F): May 4 - May 13
  • First Hard Freeze (28°F): Sep 30 - Oct 7
  • Annual Rainfall: 6-20 inches
  • Common Soils: Sandy loam, Clay, Alkaline

Plant Zone Range (zones 2-11)

2a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 5.0 – 8.0

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Mustard Greens in Wyoming

The frost window

Across Wyoming, the last spring hard freeze (28°F) clears between May 4 and May 13, and the first fall hard freeze lands between Sep 30 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 140-day window you can count on — up to 156 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.

When to start the seed

Those dates are when mustard greens goes out, not when it starts. It is sown under cover about 4 weeks ahead, so counting back from Wyoming's late-side last freeze of May 13 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.

Winter standing

Wyoming runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for mustard greens, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether mustard greens is a permanent planting or a replant-every-spring crop for you turns on your own zone within Wyoming; check its hardiness range against that before treating it as long-lived ground.

Timing tuned to sub-state frost dates — Teton County, not the statewide average.

Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.

Growing Season Fit

Mustard Greens is grown in zones 2–11, which covers every zone Wyoming contains (3b-6a). It is grown as a summer crop, so season length decides it here. Wyoming's typical season runs ~151 frost-free days against the ~50 mustard greens needs.

Frost-free days

Mustard Greens wants 50+ frost-free days; a typical Wyoming site sees ~151 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.

Growing degree days

Mustard Greens needs ~1000 GDD (base 50°F) to ripen. We haven't confirmed this against a published source yet. The state median runs ~1866 GDD (from PRISM 1991-2020 climate normals), so Wyoming's typical season clears that easily.

GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.

Soil + Drainage Fit

Mustard Greens tolerates a wide pH range (pH 5-8) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Wyoming. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5.5 and 6.5 — worth knowing before you decide whether a Wyoming soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Wyoming site is heavier clay or sits in a low spot, a raised bed lifts the roots above wet ground, or work in compost.

Your land, not the state average

Wyoming's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Mustard Greens needs about 7 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how mustard greens performs.

Check your parcel → Source: USDA NRCS SSURGO.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Wyoming soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

Before you plant mustard greens for food

Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before mustard greens goes in. What follows is Wyoming’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.

Safe to Grow Here?

What the federal record shows across Wyoming — and how to grow with it.

Federal record: High

We checked the federal record across Wyoming — 4,526 documented sites across 7 of the 8 source types we track.

The most significant on record: 64 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.

Wyoming carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds of imported, lab-tested soil grow well almost anywhere in the meantime.

Know before you grow — the guide

Sources Checked

across Wyoming

Severity Distribution

across Wyoming

High42Moderate1,188Low3,296

Highest-Severity Sites

Mining Sites · Past Producer
Superfund · Superfund NPL
PFAS Sampling · PFAS Detected
Mining Sites · Past Producer
Mining Sites · Past Producer

Know Before You Grow

  • •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
  • •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
  • •TRI facilities report what they release. Check the wind — downwind beds catch more of it.

Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.

What Else to Consider for Mustard Greens in Wyoming

The zone range tells you where mustard greens is grown — but Wyoming growers also need to think about:

Extremely short growing season (60-90 frost-free days)

Very low rainfall requires irrigation

Persistent high winds desiccate and damage plants

Growing mustard greens here specifically

Wyoming's soils run mostly loam (Aridisols), and whether that suits mustard greens's pH 5.0–8.0 preference comes down to your exact parcel, not the statewide picture.

Pull your parcel's SSURGO map unit, test pH, and amend toward mustard greens's 5.0–8.0 target before planting. How to handle it →

What to actually do about these — and the constraints that apply to every Wyoming grower, not just mustard greens — is covered on the Wyoming growing guide.

Timing shifts within Wyoming

Wyoming isn't one climate. In Teton County, the last hard freeze (28°F) holds until about Jun 16 — roughly 41 days later than the recorded state median — so plant mustard greens to your county's window, not the statewide date.

Mustard Greens needs about 50 days of frost-free season to complete its cycle. Even Teton County — Wyoming’s shortest season at 79 frost-free days — clears that by 29 days, so season length isn’t the constraint anywhere in Wyoming. What varies is your own parcel.

Across Wyoming’s 23 counties the frost-free season runs from 79 days in Teton County to 166 days in Big Horn County — a spread of 87 days, which is why a single statewide planting date misleads. The median Wyoming county sees 151 frost-free days, leaving mustard greens about 101 days of slack on a typical parcel — room for a second sowing where the season runs long.

County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Mustard Greens's 50-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

Pollinator + Wildlife Value

Mustard Greens draws honeybees and native bees (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, mustard greens can only work that bloom inside Wyoming's frost window — roughly 151 days, opening after the last 28°F freeze (May 4 - May 13) and closing at the first (Sep 30 - Oct 7), per NOAA Regional Climate Centers ACIS, 1991-2020. Pollinator value: We haven't confirmed this against a published source yet.

Wyoming Cooperative Extension

For Wyoming-specific cultivar recommendations, planting calendars, and pest pressure for mustard greens, the canonical source is University of Wyoming Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Mustard Greens native to Wyoming?

No — the USDA PLANTS Database lists Mustard Greens as introduced rather than native in the Lower 48, so it is not part of Wyoming's native flora. It grows here as a garden plant; pairing it with a few Wyoming natives keeps local pollinators fed too.

Looking for plants that belong here? The Wyoming growing guide lists plants that USDA PLANTS records growing in Wyoming and that Kew and NatureServe Explorer both list in its native range, leaving out any that NatureServe flags as exotic there or that our audit holds.

State records: USDA PLANTS Database state-distribution data (presence, not state-level nativity), accessed 2026-10-19.

Common Questions About Growing Mustard Greens in Wyoming

When can I plant Mustard Greens in Wyoming?

Wyoming's last spring hard freeze (28°F) clears between May 4 and May 13, and the first fall hard freeze lands between Sep 30 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Mustard Greens, so this page does not state whether it overwinters in Wyoming and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.

What hardiness zone is Mustard Greens grown in across Wyoming?

Wyoming spans USDA hardiness zones 3b-6a (USDA ARS PHZM 2023). Mustard Greens carries a range of zones 2-11, so the overlap zones are where outdoor growing is most reliable.

How many frost-free days does a typical Wyoming site have?

A typical Wyoming site sees ~151 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Mustard Greens needs 50+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Teton, the freeze-free season runs shorter than the state average, so verify your own county's window.

Is Mustard Greens native to Wyoming?

No — the USDA PLANTS Database lists Mustard Greens as introduced rather than native in the Lower 48, so it is not part of Wyoming's native flora. It grows here as a garden plant; pairing it with a few Wyoming natives keeps local pollinators fed too.

How should I amend the soil for Mustard Greens in Wyoming?

Mustard Greens tolerates pH 5-8 and well (dry spells) drainage (FAO ECOCROP). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Wyoming site — amend for drainage and organic matter first.

Will Mustard Greens actually grow on my specific land in Wyoming?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores mustard greens against your address's mapped soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free to start

Check your specific parcel in Wyoming

State-level data is a sketch. Your Growable Ground report scores mustard greens against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.

Three things about your lot that Wyoming mustard greens averages can't show:

Your soil pHYour frost-free days — Wyoming averages 151Your sun & shade

We read public map data around Wyoming — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the Wyoming mustard greens average

Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →

Cite this dataset

Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643

Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643

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