Unlikely — Zone Mismatch
koronivia grass (zones 10-13) does not overlap with Utah's zone range (4a-9a). Growing outdoors is unlikely without significant protection.
One zone short — what would close it
Koronivia Grass is hardy to zone 10, and the warmest ground in Utah is zone 9 — 1 zone short. Planted in open ground it will not survive a Utah winter. To grow it here, grow koronivia grass in a hoop house or unheated greenhouse — its modeled 1.5-zone lift covers this gap.
A hoop house or unheated greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 10-13 (plant) against 4-9 (Utah). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['hoop_house'] (+1.5 zones) via api/fast_sections.py Unlock Engine v2.
Koronivia Grass in Utah — the short answer
Koronivia Grass in Utah: hardy in zones 10–13, full sun, against a state median of ~175 frost-free days.
- Plant zones
- 10-13
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Utah zones
- 4a-9a
- USDA PHZM 2023
- Frost window
- Apr 12 - May 6 – Oct 8 - Oct 27
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 98 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 120 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.
Your yard isn't the whole zone.
Utah spans zones 4a-9a, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score koronivia grass against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Utah is not one climate
A single Utah answer averages 29 counties whose growing seasons are 139 days apart — from 98 frost-free days in Summit County to 237 in Washington County. Which end of that your land sits nearer changes what koronivia grass can finish before the first hard freeze.
The middle half of 29 counties runs 156–195 days, with a median of 175 days — a 139-day span end to end.
Measured across 29 Utah 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 Koronivia Grass Stands in Utah
Koronivia Grass is rated for zones 10–13 — a cold floor USDA puts at 30 to 40°F. No Utah county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Utah winters, not about koronivia grass.
Below the zone 10 floor
29 counties
- Rich County · zone 4b
- Daggett County · zone 5b
- Iron County · zone 5b
3 of 29 shown
Winter cold is the limit here — the same plant works in a container that comes under cover.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. A zone is a 10°F band of average annual extreme minimum temperature, so the floor above is the band the plant's rating denotes, not a single measured kill point. Slope, shelter and cold-air drainage routinely move a site half a zone either way from its county figure — which is the part only your address resolves.
Zone Comparison
Koronivia Grass Needs
- USDA Zones: 10-13
- Frost-Free Days: 90+
- Sun: Full Sun
- Mature size: 2 ft tall
- Drought tolerance: Medium
Utah Has
- USDA Zones: 4a-9a
- Last Hard Freeze (28°F): Apr 12 - May 6
- First Hard Freeze (28°F): Oct 8 - Oct 27
- Annual Rainfall: 5-20 inches
- Common Soils: Sandy loam, Alkaline clay, Desert sand
Plant Zone Range (zones 10-13)
Preferred Soil pH
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 Koronivia Grass in Utah
The frost window
Across Utah, the last spring hard freeze (28°F) clears between Apr 12 and May 6, and the first fall hard freeze lands between Oct 8 and Oct 27 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 155-day window you can count on — up to 198 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
Koronivia Grass is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Utah's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 120 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 35 days to spare even in Utah's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Summit 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
The zone check says koronivia grass does not survive a Utah winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on Utah under protection.
Frost-free days
Koronivia Grass wants 90+ frost-free days; a typical Utah site sees ~175 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Koronivia Grass needs ~3000 GDD (base 50°F) to ripen. The state median runs ~2690 GDD (from PRISM 1991-2020 climate normals), so Utah's typical season runs short on heat — pick a south-facing site and consider season extension.
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
Koronivia Grass tolerates a wide pH range (pH 4.5-7.5) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Utah. 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 and 6 — worth knowing before you decide whether a Utah soil test result is a problem or just a number. Drainage matters: this plant wants poorly (saturated >50% of year), well (dry spells). If your Utah site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Utah's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Koronivia Grass needs about 19 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 koronivia grass 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. Utah soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Koronivia Grass in Utah
Zone compatibility tells you about winter cold survival — but Utah growers also need to think about:
Very low rainfall — irrigation essential
Alkaline soils (pH 7.5-8.5) limit many species
High altitude frost risk in mountain valleys
Growing koronivia grass here specifically
Koronivia Grass sends medium roots and rates to zones 10–13, but much of Utah sits on slow-draining, restrictive ground (SSURGO hydrologic group D) that forks and stunts them.
Loosen a deep, stone-free bed for koronivia grass and break any compacted or hardpan layer before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Utah grower, not just koronivia grass — is covered on the Utah growing guide.
Timing shifts within Utah
Utah isn't one climate. In Summit County, the last hard freeze (28°F) holds until about Jun 10 — roughly 45 days later than the recorded state median — so plant koronivia grass to your county's window, not the statewide date.
Koronivia Grass needs about 90 days of frost-free season to complete its cycle. Even Summit County — Utah’s shortest season at 98 frost-free days — clears that by 8 days, so season length isn’t the constraint anywhere in Utah. What varies is your own parcel.
Across Utah’s 29 counties the frost-free season runs from 98 days in Summit County to 237 days in Washington County — a spread of 139 days, which is why a single statewide planting date misleads. The median Utah county sees 175 frost-free days, leaving koronivia grass about 85 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"). Koronivia Grass's 90-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Utah Cooperative Extension
For Utah-specific cultivar recommendations, planting calendars, and pest pressure for koronivia grass, the canonical source is Utah State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Koronivia Grass in Utah
When can I plant Koronivia Grass in Utah?
Utah's last spring hard freeze (28°F) clears between Apr 12 and May 6, and the first fall hard freeze lands between Oct 8 and Oct 27 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Koronivia Grass mature before first frost in Utah?
Yes — Koronivia Grass matures in 120 days (Growable Ground Plant Database), and Utah's dependable hard-freeze-free window runs 155 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 35 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Koronivia Grass grown in across Utah?
Utah spans USDA hardiness zones 4a-9a (USDA ARS PHZM 2023). Koronivia Grass carries a range of zones 10-13, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Utah site have?
A typical Utah site sees ~175 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Koronivia Grass needs 90+ 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 Summit, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for Koronivia Grass in Utah?
Koronivia Grass tolerates pH 4.5-7.5 and poorly (saturated >50% of year), 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 Utah site — amend for drainage and organic matter first.
Will Koronivia Grass actually grow on my specific land in Utah?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores koronivia grass against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Utah
State-level data is a sketch. Your Growable Ground report scores koronivia grass against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Utah koronivia grass averages can't show:
We read public map data around Utah — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Utah koronivia grass average
Explore More
Growing guides for koronivia grass
Explore Utah county by county
Utah carries 29 counties with their own USDA zone — a sample of the growing pages for koronivia grass there:
Where else koronivia grass grows
Koronivia Grass's zone band crosses state lines — these are the states closest to Utah in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Utah
Utah has a growing page for 1,038 plants — a rotating sample of the rest of the shelf.
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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