Houston, Alaska, sits in USDA hardiness zone 4a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
A short list that earns its place here — cabbage, cranberry, cilantro, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Houston, 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 Houston 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 Houston — soil, climate, flood, and parcel records. How we handle your address.
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Houston — the short answer
Houston, Alaska: USDA zone 4a, about 145 days between hard freezes, across 15K acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 6
- Matanuska-Susitna Borough normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Sep 28
- Matanuska-Susitna Borough normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~145
- Matanuska-Susitna Borough normal — NOAA 1991–2020, nearest to this town
- City area
- 15K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Matanuska-Susitna Borough’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 4a is Houston's average, not your lot's — a low corner or a tree line moves it. Against Houston's 145-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Houston
Each reading below is measured for Houston itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsHouston runs about 145 days between hard freezes (read from Matanuska-Susitna Borough, the closest normal to Houston) — 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
MeasuredHouston 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
What Grows in Houston
Every plant below cleared Houston's own zone 4a and its 145-day season. Each card opens that plant's Alaska profile. How we score.
Is it too late to plant in Houston?
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 Sep 28 — 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's on the federal record near Houston
Closest first, within ~10 miles of Houston. Listing isn't leaking, and distance isn't exposure.
- SB01800322CCDA1 001Nitrate · 1.0 mi
- Alaska Railroad Corp (arrc) - Sunshine SectionUnderground Storage Tanks · 1.0 mi
- Houston Volunteer Fire DepartmentUnderground Storage Tanks · 1.0 mi
- Lot 27 Usrs, T17n, R4wUnderground Storage Tanks · 1.0 mi
- SB01700302ABDC1 006Nitrate · 1.8 mi
- STR GROUP, LLCBrownfields · 3.7 mi
- Meadowood TESOROUnderground Storage Tanks · 3.7 mi
- Big Lake Super StoreUnderground Storage Tanks · 4.3 mi
- SB01700205ABCD2Nitrate · 4.4 mi
- Big Lake Public Safety BldgUnderground Storage Tanks · 4.4 mi
- J & M AIRCRAFTBrownfields · 4.4 mi
- BIG LAKE NAV AIDSSuperfund · 4.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Houston'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 Houston.
Total Sites
68
within ~10 miles of Houston
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Houston
Severity Distribution
within ~10 miles of Houston
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Houston, Nitrate runs higher than the national average — 40 sites within ~10 miles of Houston. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Houston
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 Houston average
Your land is one point inside Houston
Everything above resolves to Houston as a whole — one PHZM band, read across 15K acres, with hard-freeze dates borrowed from Matanuska-Susitna Borough’s record because no 30-year normal resolves at this city’s own centroid. 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 Houston Average
Houston Average
- ●USDA Zones 4a, averaged across Houston
- ●One soil character for all of Houston
- ●Frost dates read at Houston's scale: May 6 to Sep 28
YOUR Parcel
- ✓Your exact zone, not Houston's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Houston
Pull a site-specific report for your exact address in Houston, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Houston averages can't show:
We read public map data around Houston — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Houston average
How we know this about Houston
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 Matanuska-Susitna Borough’s record, because none resolves here; 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 Houston
When does frost risk typically end in Houston?
The last hard freeze (28°F) in Houston 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.
When is the first frost in Houston?
The first hard freeze (28°F) in Houston typically arrives around Sep 28, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 14, so the watching starts about Aug 29 — about 145 days after the spring freeze cleared.
How long is the growing season in Houston?
Measured between 28°F hard freezes, Houston sees about 145 frost-free days — roughly May 6 through Sep 28, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 27 to Sep 14, about 110 days.
Is the soil safe to grow vegetables in Houston?
The federal record around Houston is a meaningful one — 68 documented sites, mostly Nitrate entries (40), the nearest Nitrate record about 1.0 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 Houston?
With about 145 frost-free days between hard freezes, Houston 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 173 to 201 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 Houston's scale — its 4a band and its 145-day season. Your yard writes its own version of Houston'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 Houston’s own scale
4 of the readings below were taken at Houston's own scale — the 15,325 acres it covers and 68 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Houston's own USDA hardiness band, zones 4aUSDA PHZM 2023
- 68 documented contamination sites on the federal record near Houston, the closest Nitrate record about 1.0 miles out from the town centreFederal environmental registers
- Houston's boundary and the 15,325 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~145-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The 28°F hard-freeze dates — Houston has no normal of its own, so its county's is the closest measured readfrom Matanuska-Susitna Borough
- Soil character — no town-scale survey exists, so Houston's 15,325 acres read through its county's SSURGO summaryfrom Matanuska-Susitna County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Matanuska-Susitna County
- The growing challenges every Alaska grower plans around — written at state scale, so they stay on the state guidefrom Alaska
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Matanuska-Susitna County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Houston's 15,325 acreswhy one lot differs from the next →
- Which side of Houston you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 15,325 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 1.0 miles 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 Houston-wide figureread your own land →