Unlikely — Zone Mismatch
tree tomato (zones 12-13) does not overlap with California's zone range (4b-11a). Growing outdoors is unlikely without significant protection.
One zone short — what would close it
Tree Tomato is hardy to zone 12, and the warmest ground in California is zone 11 — 1 zone short. Planted in open ground it will not survive a California winter. To grow it here, grow tree tomato in a container and move it under cover for the coldest weeks, or give it a greenhouse.
Season extension and overwintering under cover both work at this margin. How to buy the weeks →
Zone math from 12-13 (plant) against 5-11 (California). Lift modeled by crop_engine Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.
Your yard isn't the whole zone.
California spans zones 4b-11a, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score tree tomato against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Tree Tomato Needs
- USDA Zones: 12-13
- Frost-Free Days: 270+
- Sun: Full Sun
California Has
- USDA Zones: 4b-11a
- Last Hard Freeze (28°F): Jan 19 - Mar 19
- First Hard Freeze (28°F): Nov 29 - Dec 12
- Annual Rainfall: 5-80 inches
- Common Soils: Alluvial clay, Sandy loam, Adobe clay
Plant Zone Range (zones 12-13)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Tree Tomato in California
The frost window
Across California, the last spring hard freeze (28°F) clears between Jan 19 and Mar 19, and the first fall hard freeze lands between Nov 29 and Dec 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 255-day window you can count on — up to 327 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Winter standing
California runs as cold as USDA zone 4, and no sourced winter-hardiness floor is on record for tree tomato, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether tree tomato is a permanent planting or a replant-every-spring crop for you turns on your own zone within California; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Mono County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says tree tomato does not survive a California winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on California under protection.
Frost-free days
Tree Tomato wants 270+ frost-free days; a typical California site sees ~317 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a workable window — start indoors to bank time.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Tree Tomato likes near-neutral soil (pH 5.8-7.5). That's the common-ground band across California's alluvial clay and sandy loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6.3 and 7 — worth knowing before you decide whether a California soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your California site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
California's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Tree Tomato needs about 7 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how tree tomato performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. California soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Tree Tomato in California — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 12-13 (USDA PLANTS Database)
- State Zones: 4b-11a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Jan 19 - Mar 19 to Nov 29 - Dec 12 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Tree Tomato in California
Zone compatibility tells you about winter cold survival — but California growers also need to think about:
Drought is a persistent challenge — irrigation is essential in most regions
Wildfire risk affects rural and foothill properties
Adobe clay soils in valleys drain poorly without amendment
Wide climate variation means plant selection is highly location-specific
Growing tree tomato here specifically
Tree Tomato wants pH 5.8–7.5 and rates to USDA zones 12–13, but California's soils are dominantly loam — the fit is decided by your parcel's own map unit, not the state average.
Match tree tomato to your parcel's SSURGO map unit — test pH and texture, and amend toward its 5.8–7.5 range. How to handle it →
What to actually do about these — and the constraints that apply to every California grower, not just tree tomato — is covered on the California growing guide.
Timing shifts within California
California isn't one climate. In Mono County, the last hard freeze (28°F) holds until about Jun 4 — roughly 120 days later than the recorded state median — so plant tree tomato to your county's window, not the statewide date.
Tree Tomato needs about 270 days of frost-free season to complete its cycle. 43 of California’s 57 counties give it that outright. The tightest that does is Humboldt County at 278 frost-free days — 8 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
Across California’s 57 counties the frost-free season runs from 108 days in Mono County to 365 days in Ventura County — a spread of 257 days, which is why a single statewide planting date misleads. The median California county sees 317 frost-free days, leaving tree tomato about 47 days of slack on a typical parcel — room for a second sowing where the season runs long.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Tree Tomato's 270-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Tree Tomato draws native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, tree tomato can only work that bloom inside California's frost window — roughly 317 days, opening after the last 28°F freeze (Jan 19 - Mar 19) and closing at the first (Nov 29 - Dec 12), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Tree Tomato
Tree Tomato is listed as toxic to dogs, cats (leaves, unripe fruit) at a mild level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.
California Cooperative Extension
For California-specific cultivar recommendations, planting calendars, and pest pressure for tree tomato, the canonical source is UC Agriculture and Natural Resources. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Tree Tomato in California
When can I plant Tree Tomato in California?
California's last spring hard freeze (28°F) clears between Jan 19 and Mar 19, and the first fall hard freeze lands between Nov 29 and Dec 12 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Tree Tomato, so this page does not state whether it overwinters in California and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Tree Tomato grown in across California?
California spans USDA hardiness zones 4b-11a (USDA ARS PHZM 2023). Tree Tomato carries a range of zones 12-13, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical California site have?
A typical California site sees ~317 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Tree Tomato needs 270+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Mono, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for Tree Tomato in California?
Tree Tomato prefers pH 5.8-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across California soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Tree Tomato actually grow on my specific land in California?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores tree tomato against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in California
State-level data is a sketch. Your Growable Ground report scores tree tomato against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that California tree tomato averages can't show:
We read public map data around California — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the California tree tomato average
Explore More
Growing guides for tree tomato
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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