Sisco Heights, Washington, sits in USDA hardiness zone 8b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, fig, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Sisco Heights, 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 Sisco Heights 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 Sisco Heights — soil, climate, flood, and parcel records. How we handle your address.
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Sisco Heights — the short answer
Sisco Heights, Washington: USDA zone 8b, about 208 days between hard freezes, across 9K acres of town.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- Snohomish County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Nov 9
- Snohomish County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~208
- Snohomish County normal — NOAA 1991–2020, nearest to this town
- Town area
- 9K 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 Snohomish County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 8b is Sisco Heights's average, not your lot's — a low corner or a tree line moves it. Against Sisco Heights's 208-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Sisco Heights
Each reading below is measured for Sisco Heights itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsSisco Heights runs about 208 days between hard freezes (read from Snohomish County, the closest normal to Sisco Heights) — 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
MeasuredSisco Heights 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 Sisco Heights is in
Sisco Heights sits in the Puget Lowland — EPA Level III, inside the wider Marine West Coast Forest. That is read at Sisco Heights's own centroid, and it is not what its county reads: Snohomish County is mostly North Cascades. The wider page above you is answering a different question about different ground.
What Grows in Sisco Heights
Every plant below cleared Sisco Heights's own zone 8b and its 208-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Sisco Heights?
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 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 9 — 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 Sisco Heights
Closest first, within ~10 miles of Sisco Heights. Listing isn't leaking, and distance isn't exposure.
- SCOTT PROPERTYBrownfields · 500 ft
- 31N/05E-35R01Nitrate · 0.6 mi
- 30N/06E-06E02Nitrate · 0.6 mi
- SISCO LANDFILLSuperfund · 1.0 mi
- 30N/05E-02C02Nitrate · 1.1 mi
- 31N/06E-31G01Nitrate · 1.5 mi
- 30N/05E-03J02Nitrate · 1.6 mi
- 31N/05E-25L01Nitrate · 1.6 mi
- MARYSVILLE PLANTUnderground Storage Tanks · 1.8 mi
- 30N/05E-11Q03Nitrate · 1.9 mi
- 31N/06E-30L02Nitrate · 1.9 mi
- 30N/05E-26M01Nitrate · 2.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Sisco Heights'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 Sisco Heights.
Sources Checked
within ~10 miles of Sisco Heights
Severity Distribution
within ~10 miles of Sisco Heights
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Sisco Heights, Nitrate runs higher than the national average — 288 sites within ~10 miles of Sisco Heights. 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.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Sisco Heights
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 Sisco Heights average
Your land is one point inside Sisco Heights
Everything above resolves to Sisco Heights as a whole — one PHZM band, read across 9K acres, with hard-freeze dates borrowed from Snohomish County’s record because no 30-year normal resolves at this town’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 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 Sisco Heights Average
Sisco Heights Average
- ●USDA Zones 8b, averaged across Sisco Heights
- ●One soil character for all of Sisco Heights
- ●Frost dates read at Sisco Heights's scale: Apr 15 to Nov 9
YOUR Parcel
- ✓Your exact zone, not Sisco Heights's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Sisco Heights
Pull a site-specific report for your exact address in Sisco Heights, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Sisco Heights averages can't show:
We read public map data around Sisco Heights — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Sisco Heights average
How we know this about Sisco Heights
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 Snohomish County’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 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 Sisco Heights
When does frost risk typically end in Sisco Heights?
The last hard freeze (28°F) in Sisco Heights typically lands around Apr 15, 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 6.
When is the first frost in Sisco Heights?
The first hard freeze (28°F) in Sisco Heights typically arrives around Nov 9, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 26, so the watching starts about Oct 10 — about 208 days after the spring freeze cleared.
How long is the growing season in Sisco Heights?
Measured between 28°F hard freezes, Sisco Heights sees about 208 frost-free days — roughly Apr 15 through Nov 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 26, about 173 days.
Is the soil safe to grow vegetables in Sisco Heights?
The federal record around Sisco Heights is a meaningful one — 701 documented sites, mostly Nitrate entries (288), the nearest Brownfields record under a tenth of a mile 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 I protect my plants from frost in Sisco Heights?
From about Oct 10 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 9 (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 9. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Sisco Heights's scale — its 8b band and its 208-day season. Your yard writes its own version of Sisco Heights'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 Sisco Heights’s own scale
5 of the readings below were taken at Sisco Heights's own scale — the 8,844 acres it covers and 701 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Sisco Heights's own USDA hardiness band, zones 8bUSDA PHZM 2023
- 701 documented contamination sites on the federal record near Sisco Heights, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- Sisco Heights's boundary and the 8,844 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~208-day seasonGrowable Ground crop-matching engine
- Sisco Heights sits in the Puget Lowland — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Sisco Heights has no normal of its own, so its county's is the closest measured readfrom Snohomish County
- Soil character — no town-scale survey exists, so Sisco Heights's 8,844 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 Sisco Heights's 8,844 acreswhy one lot differs from the next →
- Which side of Sisco Heights you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 8,844 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Sisco Heights-wide figureread your own land →
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