Index, Washington, sits in USDA hardiness zone 8b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
A short list that earns its place here — cabbage, fig, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Index, 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 Index 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 Index — soil, climate, flood, and parcel records. How we handle your address.
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Index — the short answer
Index, Washington: USDA zone 8b, about 232 days between hard freezes, across 147 acres of town.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~232
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 147 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 8b is Index's average, not your lot's — a low corner or a tree line moves it. Against Index's 232-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Index
Each reading below is measured for Index itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredIndex runs about 232 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
MeasuredIndex sits in USDA hardiness zone 8b.
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 Index is in
Index sits in the North Cascades — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Index's own centroid rather than borrowed from Snohomish County.
What Grows in Index
Every plant below cleared Index's own zone 8b and its 232-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Index?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Feb 28; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 15 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
What's on the federal record near Index
Closest first, within ~10 miles of Index. Listing isn't leaking, and distance isn't exposure.
- Helena ProspectMining · 1.2 mi
- REIDER ROAD RADIO/DEER CR FLAT 2740-BUnderground Storage Tanks · 1.4 mi
- AlphaMining · 2.0 mi
- Lake Serene MineMining · 2.1 mi
- North StarMining · 2.2 mi
- North Star ProspectMining · 2.3 mi
- Index-IndependentMining · 2.3 mi
- Lake SereneMining · 2.3 mi
- Index Bornite MineMining · 2.5 mi
- ReiterMining · 2.5 mi
- Index Bornite ProspectMining · 2.7 mi
- Gunn Peak ProspectMining · 2.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Index'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 Index.
Total Sites
256
within ~10 miles of Index
Risk Level
High
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Index
Severity Distribution
within ~10 miles of Index
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Index, Mining runs higher than the national average — 215 sites within ~10 miles of Index. That's not a problem with your land — it's information about it.
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 soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Index
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 Index average
Your land is one point inside Index
Everything above resolves to Index as a whole — one PHZM band and one 28°F frost record, read across 147 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 town 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 Index Average
Index Average
- ●USDA Zones 8b, averaged across Index
- ●One soil character for all of Index
- ●Frost dates read at Index's scale: Mar 28 to Nov 15
YOUR Parcel
- ✓Your exact zone, not Index's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Index
Pull a site-specific report for your exact address in Index, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Index averages can't show:
We read public map data around Index — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Index average
How we know this about Index
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Index’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 town grain anywhere on this page — there is no town-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 Index
When does frost risk typically end in Index?
The last hard freeze (28°F) in Index typically lands around Mar 28, 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 18.
When is the first frost in Index?
The first hard freeze (28°F) in Index typically arrives around Nov 15, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 1, so the watching starts about Oct 16 — about 232 days after the spring freeze cleared.
How long is the growing season in Index?
Measured between 28°F hard freezes, Index sees about 232 frost-free days — roughly Mar 28 through Nov 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 18 to Nov 1, about 197 days.
Is the soil safe to grow vegetables in Index?
The federal record around Index runs heavier than most — 256 documented sites, mostly Mining entries (215), the nearest Mining record about 1.2 miles 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 Index?
From about Oct 16 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 Nov 15 (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 Nov 15. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Index's scale — its 8b band and its 232-day season. Your yard writes its own version of Index'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 Index’s own scale
6 of the readings below were taken at Index's own scale — its own ~232-day season between 28°F freezes, the 147 acres it covers and 256 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Index's own USDA hardiness band, zones 8bUSDA PHZM 2023
- Index's own 28°F hard-freeze dates, about Mar 28 and Nov 15 and the ~232-day span between themNOAA 1991–2020 Climate Normals
- 256 documented contamination sites on the federal record near Index, the closest Mining record about 1.2 miles out from the town centreFederal environmental registers
- Index's boundary and the 147 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~232-day seasonGrowable Ground crop-matching engine
- The ecoregion at Index's own centroid, the North CascadesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Index's 147 acres read through its county's SSURGO summaryfrom Snohomish County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Snohomish 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 Snohomish County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Index's 147 acreswhy one lot differs from the next →
- Which side of Index you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 147 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Mining record about 1.2 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 Index-wide figureread your own land →
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