Emerald Lake Hills, California, sits in USDA hardiness zone 9b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
The conditions favor okra, meyer lemon, california poppy, and artichoke, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Emerald Lake Hills, 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 Emerald Lake Hills 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 Emerald Lake Hills — soil, climate, flood, and parcel records. How we handle your address.
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Emerald Lake Hills — the short answer
Emerald Lake Hills, California: USDA zone 9b, about 341 days between hard freezes, across 756 acres of town.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Dec 22
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~341
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 756 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 9b is Emerald Lake Hills's average, not your lot's — a low corner or a tree line moves it. Against Emerald Lake Hills's 341-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Emerald Lake Hills
Each reading below is measured for Emerald Lake Hills itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredEmerald Lake Hills runs about 341 days between hard freezes — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredEmerald Lake Hills sits in USDA hardiness zone 9b.
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 Emerald Lake Hills is in
Emerald Lake Hills sits in the Central California Foothills and Coastal Mountains — EPA Level III, inside the wider Mediterranean California. That is read at Emerald Lake Hills's own centroid, and it is not what its county reads: San Mateo County is mostly Coast Range. The wider page above you is answering a different question about different ground.
What Grows in Emerald Lake Hills
Every plant below cleared Emerald Lake Hills's own zone 9b and its 341-day season. Each card opens that plant's California profile. How we score.
Is it too late to plant in Emerald Lake Hills?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 22 — long-season crops need about 90 days of runway, quick greens only 30. Here the calendar nearly circles: cool-season crops take the winter shift, and the next window is always close.
Documented around Emerald Lake Hills
Spotted lanternfly documented 20 miles from Emerald Lake Hills, first recorded 2023. What to watch for.
What's on the federal record near Emerald Lake Hills
Closest first, within ~10 miles of Emerald Lake Hills. Listing isn't leaking, and distance isn't exposure.
- BRENDAN ROYERBrownfields · 2200 ft
- CITY OF REDWOOD CITY GLENLOCK WATER STABrownfields · 2600 ft
- CANYON GAS & PROPANEUnderground Storage Tanks · 0.5 mi
- CANYON AUTO SERVICEBrownfields · 0.5 mi
- CITY OF REDWOOD CITYBrownfields · 0.6 mi
- AT&T MOBILITYBrownfields · 0.7 mi
- ANDREW KIRMSEBrownfields · 0.7 mi
- REDWOOD CITY SCHOOL DIST/ROY CLOUDBrownfields · 0.7 mi
- HYDROSTATIC TEST T32 REDWOOD CITYBrownfields · 0.7 mi
- BILL STEVENSBrownfields · 0.7 mi
- LAVONNE RICHARDSONBrownfields · 0.9 mi
- CRYSTAL LUBrownfields · 1.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Emerald Lake Hills'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 Emerald Lake Hills.
Total Sites
3,912
within ~10 miles of Emerald Lake Hills
Risk Level
Elevated
Highest-severity
14 Superfund sites
Sources Checked
within ~10 miles of Emerald Lake Hills
Severity Distribution
within ~10 miles of Emerald Lake Hills
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Emerald Lake Hills, Brownfields runs higher than the national average — 3,541 sites within ~10 miles of Emerald Lake Hills. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Emerald Lake Hills
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 Emerald Lake Hills average
Your land is one point inside Emerald Lake Hills
Everything above resolves to Emerald Lake Hills as a whole — one PHZM band and one 28°F frost record, read across 756 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 Emerald Lake Hills Average
Emerald Lake Hills Average
- ●USDA Zones 9b, averaged across Emerald Lake Hills
- ●One soil character for all of Emerald Lake Hills
- ●Frost dates read at Emerald Lake Hills's scale: Jan 15 to Dec 22
YOUR Parcel
- ✓Your exact zone, not Emerald Lake Hills's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Emerald Lake Hills
Pull a site-specific report for your exact address in Emerald Lake Hills, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Emerald Lake Hills averages can't show:
We read public map data around Emerald Lake Hills — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Emerald Lake Hills average
How we know this about Emerald Lake Hills
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 Emerald Lake Hills’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 Emerald Lake Hills
When does frost risk typically end in Emerald Lake Hills?
The last hard freeze (28°F) in Emerald Lake Hills typically lands around Jan 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 Feb 5.
When is the first frost in Emerald Lake Hills?
The first hard freeze (28°F) in Emerald Lake Hills typically arrives around Dec 22, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Dec 8, so the watching starts about Nov 22 — about 341 days after the spring freeze cleared.
How long is the growing season in Emerald Lake Hills?
Measured between 28°F hard freezes, Emerald Lake Hills sees about 341 frost-free days — roughly Jan 15 through Dec 22, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 5 to Dec 8, about 306 days.
Is the soil safe to grow vegetables in Emerald Lake Hills?
The federal record around Emerald Lake Hills is a meaningful one — 3,912 documented sites, mostly Brownfields entries (3,541), the nearest Brownfields record about 0.4 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 I protect my plants from frost in Emerald Lake Hills?
From about Nov 22 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 Dec 22 (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 Dec 22. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Emerald Lake Hills's scale — its 9b band and its 341-day season. Your yard writes its own version of Emerald Lake Hills'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 Emerald Lake Hills’s own scale
7 of the readings below were taken at Emerald Lake Hills's own scale — its own ~341-day season between 28°F freezes, the 756 acres it covers and 3,912 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Emerald Lake Hills's own USDA hardiness band, zones 9bUSDA PHZM 2023
- Emerald Lake Hills's own 28°F hard-freeze dates, about Jan 15 and Dec 22 and the ~341-day span between themNOAA 1991–2020 Climate Normals
- 3,912 documented contamination sites on the federal record near Emerald Lake Hills, the closest Brownfields record about 0.4 miles out from the town centreFederal environmental registers
- Emerald Lake Hills's boundary and the 756 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~341-day seasonGrowable Ground crop-matching engine
- Emerald Lake Hills sits in the Central California Foothills and Coastal Mountains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Emerald Lake Hillslydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Emerald Lake Hills's 756 acres read through its county's SSURGO summaryfrom San Mateo County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom San Mateo County
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom San Mateo County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Emerald Lake Hills's 756 acreswhy one lot differs from the next →
- Which side of Emerald Lake Hills you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 756 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 0.4 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 Emerald Lake Hills-wide figureread your own land →