Union Gap, Washington, sits in USDA hardiness zone 7a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Among the crops suited to this profile: cabbage, hazelnut, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Union Gap, 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 Union Gap 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 Union Gap — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Union Gap — the short answer
Union Gap, Washington: USDA zone 7a, about 211 days between hard freezes, across 4K acres of city.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~211
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 4K 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 7a is Union Gap's average, not your lot's — a low corner or a tree line moves it. Against Union Gap's 211-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Union Gap
Each reading below is measured for Union Gap itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredUnion Gap runs about 211 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredUnion Gap sits in USDA hardiness zone 7a.
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 Union Gap is in
Union Gap sits in the Columbia Plateau — EPA Level III, inside the wider North American Deserts. That is read at Union Gap's own centroid rather than borrowed from Yakima County.
What Grows in Union Gap
Every plant below cleared Union Gap's own zone 7a and its 211-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Union Gap?
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 Mar 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 26 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near Union Gap
Closest first, within ~10 miles of Union Gap. Listing isn't leaking, and distance isn't exposure.
- MACRO PLASTICS WASHINGTON IPL GLOBALToxics Release Inventory · 400 ft
- MACRO PLASTICS WASHINGTONToxics Release Inventory · 1400 ft
- PACIFIC POWER & LIGHT UNION GAPUnderground Storage Tanks · 2000 ft
- THERMOFORMING SYSTEMS LLCBrownfields · 2300 ft
- WEYHAEUSER COMPANY UNION GAPUnderground Storage Tanks · 2300 ft
- FEDEX GROUND YAKIMABrownfields · 2500 ft
- WASHINGTON BEEF INCUnderground Storage Tanks · 2600 ft
- NOEL FOODS INCUnderground Storage Tanks · 0.5 mi
- ORCHARD RITE UNION GAPToxics Release Inventory · 0.5 mi
- ORCHARD RITE UNION GAPBrownfields · 0.5 mi
- COSTCO WHOLESALE 1013Brownfields · 0.6 mi
- COSTCO WHOLESALE #1013Underground Storage Tanks · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Union Gap'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 Union Gap.
Sources Checked
within ~10 miles of Union Gap
Severity Distribution
within ~10 miles of Union Gap
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Union Gap, Underground Storage Tanks runs higher than the national average — 447 sites within ~10 miles of Union Gap. That's not a problem with your land — it's information about it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Union Gap
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 Union Gap average
Your land is one point inside Union Gap
Everything above resolves to Union Gap as a whole — one PHZM band and one 28°F frost record, read across 4K 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 city 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 Union Gap Average
Union Gap Average
- ●USDA Zones 7a, averaged across Union Gap
- ●One soil character for all of Union Gap
- ●Frost dates read at Union Gap's scale: Mar 29 to Oct 26
YOUR Parcel
- ✓Your exact zone, not Union Gap's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Union Gap
Pull a site-specific report for your exact address in Union Gap, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Union Gap averages can't show:
We read public map data around Union Gap — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Union Gap average
How we know this about Union Gap
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Union Gap’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 city grain anywhere on this page — there is no city-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 Union Gap
When does frost risk typically end in Union Gap?
The last hard freeze (28°F) in Union Gap typically lands around Mar 29, 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 Apr 19.
When is the first frost in Union Gap?
The first hard freeze (28°F) in Union Gap typically arrives around Oct 26, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 12, so the watching starts about Sep 26 — about 211 days after the spring freeze cleared.
How long is the growing season in Union Gap?
Measured between 28°F hard freezes, Union Gap sees about 211 frost-free days — roughly Mar 29 through Oct 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 19 to Oct 12, about 176 days.
Is the soil safe to grow vegetables in Union Gap?
The federal record around Union Gap runs heavier than most — 687 documented sites, mostly Underground Storage Tanks entries (447), the nearest Toxics Release Inventory record under a tenth of a mile out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Union Gap?
From about Sep 26 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 26 (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 26. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Union Gap's scale — its 7a band and its 211-day season. Your yard writes its own version of Union Gap'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 Union Gap’s own scale
6 of the readings below were taken at Union Gap's own scale — its own ~211-day season between 28°F freezes, the 3,569 acres it covers and 687 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Union Gap's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Union Gap's own 28°F hard-freeze dates, about Mar 29 and Oct 26 and the ~211-day span between themNOAA 1991–2020 Climate Normals
- 687 documented contamination sites on the federal record near Union Gap, the closest Toxics Release Inventory record under a tenth of a mile out from the town centreFederal environmental registers
- Union Gap's boundary and the 3,569 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~211-day seasonGrowable Ground crop-matching engine
- The ecoregion at Union Gap's own centroid, the Columbia PlateauUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Union Gap's 3,569 acres read through its county's SSURGO summaryfrom Yakima County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Yakima County
- The growing challenges every Washington grower plans around — written at state scale, so they stay on the state guidefrom Washington
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Yakima County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Union Gap's 3,569 acreswhy one lot differs from the next →
- Which side of Union Gap you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,569 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Toxics Release Inventory 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 Union Gap-wide figureread your own land →