Merced County, in California, sits in USDA hardiness zone 9a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Well-matched crops include artichoke, fig, california poppy, and cabbage, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Merced County lies within the San Joaquin Valley and the California Central Valley — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Merced County holds more than one microclimate.
Soils and elevations shift across Merced County, so your frost dates and drainage aren't the county average. 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 Merced County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Merced County — the short answer
Merced County, California: USDA zone 9a, about 318 days between hard freezes, across 1.2M acres.
- USDA zone
- 9a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 21
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Dec 5
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~318
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.2M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 9a is Merced County's average, not your lot's — a low corner or a tree line moves it. Against Merced County's 318-day season, see what your own ground reads.
Heat and winter chill in Merced County
Across a year, Merced County accumulates about 4,517 growing degree days above 50°F, about 760 more than the middle California county — ahead of 40 of California’s 57 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Winter banks about 1,200 hours below 45°F, 13 more than the California middle of 1,187. Chill is what tells a fruit tree its dormancy is over, and it is set by climate rather than by anything you can build.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Merced County
Across Merced County, the ground is predominantly Alfisols, where Delhi, Atwater, and Fresno are the most extensive named soil series. The soil is generally well drained with a clay loam surface. Topsoil pH runs about 6.7–7.9, neutral. Rainfall drains through hydrologic group D soils.
Soil order
Alfisols
Drainage
Well drained
Hydric soils
29%
Soil still varies lot by lot — soil types explained.
How the ground varies across Merced County
The USDA soil survey maps 45% of Merced County as well drained — but another 52% drains differently: 15% moderately well drained, 13% poorly drained.
Delhi is the most extensive named soil at 5% of mapped acres, then Atwater (3%) and Fresno (3%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Merced County
Each reading below is measured for Merced County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Merced County are well drained, in hydrologic group D — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Merced County runs about pH 6.7–7.9, on the alkaline side.
Many vegetables cope, but acid-lovers like blueberries struggle, and iron and manganese lock up above about pH 7.5 — leaves yellow between the veins even in rich soil.
Elemental sulfur and generous organic matter lower pH slowly for the beds that need it; test first so you add only what the soil actually calls for.
USDA NRCS SSURGO
Wet ground
MeasuredAbout 29% of Merced County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredMerced County runs about 318 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
The kind of country Merced County is in
Merced County spans 2 EPA Level III ecoregions — Central California Valley (77%) and Central California Foothills and Coastal Mountains (23%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Merced County
We scored all 1,086 plants against Merced County's own USDA zone 9a and its own 318-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's California profile.
Is it too late to plant in Merced County?
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 Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 21 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 5 — long-season crops need about 90 days of runway, quick greens only 30. With almost year-round growing weather, timing is about heat and rainfall more than frost — some bench is always in play.
Documented around Merced County
- monarch butterfly4 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Merced County
USGS estimates 677,084 lb of Glyphosate on Merced County farmland in 2019, its largest by weight, ahead of Metolachlor & Metolachlor-s (32,791 lb) and Methoxyfenozide (32,507 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Merced County — and how to grow with it.
We checked the federal record across Merced County — 2,292 documented sites across 7 of the 9 source types we track.
The most significant on record: 4 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Merced County carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Merced County
Closest first, across Merced County. Listing isn't leaking, and distance isn't exposure.
- 009S012E05D001MNitrate · 2.0 mi
- 009S011E10M001MNitrate · 3.0 mi
- THRNER ISLANC FARMSBrownfields · 3.7 mi
- 009S012E17B001MNitrate · 3.7 mi
- 009S011E16H001MNitrate · 3.7 mi
- WOLFSEN LAND & CATTLEBrownfields · 4.7 mi
- BOWLES FARMING COMPANY INCBrownfields · 5.3 mi
- 009S011E20J003MNitrate · 5.3 mi
- 009S011E20J002MNitrate · 5.3 mi
- 009S011E20J001MNitrate · 5.3 mi
- PALAZZO FARMING, INC.Brownfields · 5.4 mi
- 009S012E02K002MNitrate · 5.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Merced County'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 Merced County.
Sources Checked
across Merced County
Severity Distribution
across Merced County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Merced County, two things run higher than the national average across Merced County — Nitrate (876 sites) and Brownfields (1,225 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.
Brownfields: Brownfield sites are former commercial or industrial properties where legacy soil contamination (heavy metals, PAHs, petroleum compounds) may persist.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check EPA brownfield remediation status — many sites have completed cleanup with institutional controls.
Check your specific parcel in Merced County
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 Merced County average
Your land is one point inside Merced County
Everything above resolves to Merced County as a whole — one PHZM band and one county frost record, read across 1.2M 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 county 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 county average.
Your Lot vs the Merced County Average
Merced County Average
- ●USDA Zones 9a, averaged across Merced County
- ●One soil character for all of Merced County
- ●Frost dates read at Merced County's scale: Jan 21 to Dec 5
YOUR Parcel
- ✓Your exact zone, not Merced County's 9a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Merced County
Pull a site-specific report for your exact address in Merced County, California — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Merced County averages can't show:
We read public map data around Merced County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Merced County average
How we know this about Merced County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Merced County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Merced County
When does frost risk typically end in Merced County?
The last hard freeze (28°F) in Merced County typically lands around Jan 21, 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 11.
How long is the growing season in Merced County?
Measured between 28°F hard freezes, Merced County sees about 318 frost-free days — roughly Jan 21 through Dec 5, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 11 to Nov 21, about 283 days.
Is the soil safe to grow vegetables in Merced County?
The federal record around Merced County runs heavier than most — 2,292 documented sites, mostly Brownfields entries (1,225), the nearest Nitrate record about 2.0 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.
Everything above is measured at Merced County's scale — its 9a band and its 318-day season. Your yard writes its own version of Merced County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads California's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Merced County’s own scale
9 of the readings below were taken at Merced County's own scale — its own ~318-day span between 28°F freezes, the 3 most extensive soil series mapped here and 2,292 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Merced County's own USDA hardiness band, zones 9aUSDA PHZM 2023
- Merced County's own 28°F hard-freeze dates and its ~318-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Merced CountyUSDA NRCS SSURGO
- 2,292 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 2.0 miles outFederal environmental registers
- Merced County's boundary and the 1,240,332 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9a and a ~318-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Merced County spans, Central California Valley the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Merced County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Merced County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every California grower plans around — written at state scale, so they stay on the state guidefrom California
What this page can’t tell you
- How the season shifts across Merced County — the ~318 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Merced County's 1,240,332 acreswhy one lot differs from the next →
- Which of those 2,292 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Merced Countyread your own land →