Yes — Strong Match
tatsoi is grown in zones 2-11, which covers every zone Arizona contains (5b-10b). Whether the season is long enough is the question that remains.
Tatsoi in Arizona — the short answer
Tatsoi in Arizona: grown in zones 2–11, part sun, against a state median of ~266 frost-free days.
- Plant zones
- Grown as an annual — see the growing season
- Growing season, not a hardiness zone
- Arizona zones
- 5b-10b
- USDA PHZM 2023
- Frost window
- Feb 1 - Apr 2 – Nov 13 - Dec 12
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 150 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 45 days
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Tatsoi is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Arizona site runs ~266 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score tatsoi against your land's actual frost dates, sun, and soil.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Arizona is not one climate
A single Arizona answer averages 15 counties whose growing seasons are 195 days apart — from 150 frost-free days in Coconino County to 345 in Maricopa County. Which end of that your land sits nearer changes what tatsoi can finish before the first hard freeze.
The middle half of 15 counties runs 207–316 days, with a median of 266 days — a 195-day span end to end.
Measured across 15 Arizona counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where in Arizona Fits Best
Even within Arizona's zones 5b-10b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for tatsoi (USDA PHZM 2023):
Zone Comparison
Tatsoi Needs
- USDA Zones: 2-11
- Frost-Free Days: 40+
- Sun: Part SunWe haven't confirmed this against a published source yet.
- Mature size: 8 in tallWe haven't confirmed this against a published source yet.
- Picking window: ~21 days of harvestWe haven't confirmed this against a published source yet.
- Drought tolerance: LowWe haven't confirmed this against a published source yet.
Arizona Has
- USDA Zones: 5b-10b
- Last Hard Freeze (28°F): Feb 1 - Apr 2
- First Hard Freeze (28°F): Nov 13 - Dec 12
- Annual Rainfall: 3-25 inches
- Common Soils: Caliche, Sandy loam, Desert pavement
Plant Zone Range (zones 2-11)
Preferred Soil pH
We haven't confirmed this against a published source yet.
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Tatsoi in Arizona
The frost window
Across Arizona, the last spring hard freeze (28°F) clears between Feb 1 and Apr 2, and the first fall hard freeze lands between Nov 13 and Dec 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 225-day window you can count on — up to 314 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.
When to start the seed
Those dates are when tatsoi goes out, not when it starts. It is sown under cover about 4 weeks ahead, so counting back from Arizona's late-side last freeze of Apr 2 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Days to maturity vs. the window
At 45 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 180 days to spare even in Arizona's tightest freeze scenario — room for a later start or a second sowing.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
Tatsoi is grown in zones 2–11, which covers every zone Arizona contains (5b-10b). It is grown as a summer crop, so season length decides it here. Arizona's typical season runs ~266 frost-free days against the ~40 tatsoi needs.
Frost-free days
Tatsoi wants 40+ frost-free days; a typical Arizona site sees ~266 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Tatsoi needs ~950 GDD (base 50°F) to ripen. We haven't confirmed this against a published source yet. The state median runs ~3945 GDD (from PRISM 1991-2020 climate normals), so Arizona's typical season clears that easily.
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
Tatsoi likes near-neutral soil (pH 5-7). That's the common-ground band across Arizona's caliche and sandy loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 5.5 and 6.5 — worth knowing before you decide whether a Arizona soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Arizona site is heavier clay or sits in a low spot, a raised bed lifts the roots above wet ground, or work in compost. pH range, preferred pH and drainage need: We haven't confirmed this against a published source yet.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Arizona soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant tatsoi for food
Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before tatsoi goes in. What follows is Arizona’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.
Safe to Grow Here?
What the federal record shows across Arizona — and how to grow with it.
We checked the federal record across Arizona — 18,099 documented sites across 6 of the 8 source types we track.
The most significant on record: 184 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Arizona 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 of imported, lab-tested soil grow well almost anywhere in the meantime.
Sources Checked
across Arizona
Severity Distribution
across Arizona
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Arizona, Mining runs higher than the national average — 6,160 sites across Arizona. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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.
Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.
What Else to Consider for Tatsoi in Arizona
The zone range tells you where tatsoi is grown — but Arizona growers also need to think about:
Extreme heat exceeding 110F stresses most plants
Minimal rainfall requires drip irrigation
Caliche hardpan prevents root penetration without breaking through
What to actually do about these — and the constraints that apply to every Arizona grower, not just tatsoi — is covered on the Arizona growing guide.
Timing shifts within Arizona
Tatsoi needs about 40 days of frost-free season to complete its cycle. Even Coconino County — Arizona’s shortest season at 150 frost-free days — clears that by 110 days, so season length isn’t the constraint anywhere in Arizona. What varies is your own parcel.
Across Arizona’s 15 counties the frost-free season runs from 150 days in Coconino County to 345 days in Maricopa County — a spread of 195 days, which is why a single statewide planting date misleads. The median Arizona county sees 266 frost-free days, leaving tatsoi about 226 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"). Tatsoi's 40-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
Tatsoi draws honeybees and native bees (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, tatsoi can only work that bloom inside Arizona's frost window — roughly 266 days, opening after the last 28°F freeze (Feb 1 - Apr 2) and closing at the first (Nov 13 - Dec 12), per NOAA Regional Climate Centers ACIS, 1991-2020. Pollinator value: We haven't confirmed this against a published source yet.
Arizona Cooperative Extension
For Arizona-specific cultivar recommendations, planting calendars, and pest pressure for tatsoi, the canonical source is University of Arizona Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Tatsoi native to Arizona?
No — the USDA PLANTS Database lists Tatsoi as introduced rather than native in the Lower 48, so it is not part of Arizona's native flora. It grows here as a garden plant; pairing it with a few Arizona natives keeps local pollinators fed too.
Looking for plants that belong here? The Arizona growing guide lists plants that USDA PLANTS records growing in Arizona and that Kew and NatureServe Explorer both list in its native range, leaving out any that NatureServe flags as exotic there or that our audit holds.
State records: USDA PLANTS Database state-distribution data (presence, not state-level nativity), accessed 2026-10-19.
Common Questions About Growing Tatsoi in Arizona
When can I plant Tatsoi in Arizona?
Arizona's last spring hard freeze (28°F) clears between Feb 1 and Apr 2, and the first fall hard freeze lands between Nov 13 and Dec 12 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Tatsoi mature before first frost in Arizona?
Yes — Tatsoi matures in 45 days (Growable Ground Plant Database), and Arizona's dependable hard-freeze-free window runs 225 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 180 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Tatsoi grown in across Arizona?
Arizona spans USDA hardiness zones 5b-10b (USDA ARS PHZM 2023). Tatsoi carries a range of zones 2-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Arizona site have?
A typical Arizona site sees ~266 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Tatsoi needs 40+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Tatsoi native to Arizona?
No — the USDA PLANTS Database lists Tatsoi as introduced rather than native in the Lower 48, so it is not part of Arizona's native flora. It grows here as a garden plant; pairing it with a few Arizona natives keeps local pollinators fed too.
How should I amend the soil for Tatsoi in Arizona?
Tatsoi prefers pH 5-7 and well (dry spells) drainage. We haven't confirmed this against a published source yet. That sits in the common-ground band across Arizona soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Tatsoi actually grow on my specific land in Arizona?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores tatsoi against your address's mapped soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Arizona
State-level data is a sketch. Your Growable Ground report scores tatsoi against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that Arizona tatsoi averages can't show:
We read public map data around Arizona — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Arizona tatsoi average
Explore More
Growing guides for tatsoi
Explore Arizona county by county
Arizona carries 15 counties with their own USDA zone — a sample of the growing pages for tatsoi there:
Where else tatsoi grows
Tatsoi's zone band crosses state lines — these are the states closest to Arizona in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Arizona
Arizona has a growing page for 1,036 plants — a rotating sample of the rest of the shelf.
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