Malta, Idaho, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Growers here do well with cabbage, blackberry, california poppy, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Malta, 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 Malta 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 Malta — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Malta — the short answer
Malta, Idaho: USDA zone 6a, about 146 days between hard freezes, across 883 acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 3
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~146
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 883 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 6a is Malta's average, not your lot's — a low corner or a tree line moves it. Against Malta's 146-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Malta
Each reading below is measured for Malta itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMalta runs about 146 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
MeasuredMalta sits in USDA hardiness zone 6a.
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 Malta is in
Malta sits in the Northern Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at Malta's own centroid rather than borrowed from Cassia County.
What Grows in Malta
Every plant below cleared Malta's own zone 6a and its 146-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Malta?
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 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 3 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
What's on the federal record near Malta
Closest first, within ~10 miles of Malta. Listing isn't leaking, and distance isn't exposure.
- BENNETT SERVICEUnderground Storage Tanks · 300 ft
- LEVON WILLETTUnderground Storage Tanks · 300 ft
- MALTA FUEL LLCUnderground Storage Tanks · 600 ft
- RAFT RIVER RURAL ELECTRICUnderground Storage Tanks · 1300 ft
- 13S 26E 01CCC1Nitrate · 2600 ft
- RAFT RIVER HIGHWAY DISTUnderground Storage Tanks · 0.5 mi
- USFS MALTA WORK CENTERUnderground Storage Tanks · 0.7 mi
- MALTA BUS COMPOUNDUnderground Storage Tanks · 0.7 mi
- RAFT RIVER SPRINGDALE FARMUnderground Storage Tanks · 0.7 mi
- RAFT RIVER GEOTHERMAL SITEUnderground Storage Tanks · 0.7 mi
- 13S 27E 18BD 2Nitrate · 1.4 mi
- 13S 26E 22ADC1Nitrate · 2.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Malta'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 Malta.
Sources Checked
within ~10 miles of Malta
Severity Distribution
within ~10 miles of Malta
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Malta, two things run higher than the national average within ~10 miles of Malta — Nitrate (36 sites) and Mining (3 sites). That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Malta
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 Malta average
Your land is one point inside Malta
Everything above resolves to Malta as a whole — one PHZM band and one 28°F frost record, read across 883 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 Malta Average
Malta Average
- ●USDA Zones 6a, averaged across Malta
- ●One soil character for all of Malta
- ●Frost dates read at Malta's scale: May 10 to Oct 3
YOUR Parcel
- ✓Your exact zone, not Malta's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Malta
Pull a site-specific report for your exact address in Malta, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Malta averages can't show:
We read public map data around Malta — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Malta average
How we know this about Malta
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 Malta’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 Malta
When does frost risk typically end in Malta?
The last hard freeze (28°F) in Malta typically lands around May 10, 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 31.
When is the first frost in Malta?
The first hard freeze (28°F) in Malta typically arrives around Oct 3, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 19, so the watching starts about Sep 3 — about 146 days after the spring freeze cleared.
How long is the growing season in Malta?
Measured between 28°F hard freezes, Malta sees about 146 frost-free days — roughly May 10 through Oct 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 31 to Sep 19, about 111 days.
Is the soil safe to grow vegetables in Malta?
The federal record around Malta shows 50 documented sites, mostly Nitrate entries (36), the nearest Underground Storage Tanks record under a tenth of a mile out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do gardeners stretch the season in Malta?
With about 146 frost-free days between hard freezes, Malta 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 174 to 202 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 10 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Malta's scale — its 6a band and its 146-day season. Your yard writes its own version of Malta'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 Malta’s own scale
6 of the readings below were taken at Malta's own scale — its own ~146-day season between 28°F freezes, the 883 acres it covers and 50 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Malta's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Malta's own 28°F hard-freeze dates, about May 10 and Oct 3 and the ~146-day span between themNOAA 1991–2020 Climate Normals
- 50 documented contamination sites on the federal record near Malta, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Malta's boundary and the 883 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~146-day seasonGrowable Ground crop-matching engine
- The ecoregion at Malta's own centroid, the Northern Basin and RangeUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Malta's 883 acres read through its county's SSURGO summaryfrom Cassia County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Cassia County
- The growing challenges every Idaho grower plans around — written at state scale, so they stay on the state guidefrom Idaho
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Cassia County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Malta's 883 acreswhy one lot differs from the next →
- Which side of Malta you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 883 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Malta-wide figureread your own land →
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