Generally — Most Areas
Swiss chard (zones 2-11) suits most of Florida (8b-12a) — zones 8-11 are in range, and the rest of the state is the exception.
Swiss Chard in Florida — the short answer
Swiss Chard in Florida: hardy in zones 2–11, part sun, against a state median of ~320 frost-free days.
- Plant zones
- 2-11
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Florida zones
- 8b-12a
- USDA PHZM 2023
- Frost window
- Jan 25 - Feb 10 – Dec 7 - Dec 18
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 281 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 55 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.
Florida spans zones 8b-12a, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score swiss chard against your land's actual soil, sun, and frost.
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Florida is not one climate
A single Florida answer averages 67 counties whose growing seasons are 84 days apart — from 281 frost-free days in Holmes County to 365 in Sarasota County. Which end of that your land sits nearer changes what swiss chard can finish before the first hard freeze.
The middle half of 67 counties runs 300–333 days, with a median of 320 days — a 84-day span end to end.
Measured across 67 Florida 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 Florida Fits Best
Even within Florida's zones 8b-12a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for swiss chard (USDA PHZM 2023):
Zone Comparison
Swiss Chard Needs
- USDA Zones: 2-11
- Frost-Free Days: 160+
- Sun: Part Sun
- Mature size: 1.5 ft tall
- Picking window: ~90 days of harvest
- Drought tolerance: Medium
Florida Has
- USDA Zones: 8b-12a
- Last Hard Freeze (28°F): Jan 25 - Feb 10
- First Hard Freeze (28°F): Dec 7 - Dec 18
- Annual Rainfall: 50-65 inches
- Common Soils: Sandy, Muck (Everglades), Shell-rock (Keys)
Plant Zone Range (zones 2-11)
Preferred Soil pH
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 Swiss Chard in Florida
The frost window
Across Florida, the last spring hard freeze (28°F) clears between Jan 25 and Feb 10, and the first fall hard freeze lands between Dec 7 and Dec 18 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 300-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.
Frost tenderness
Swiss Chard is frost-tender — FAO ECOCROP puts its killing temperature at 32°F — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
When to start the seed
Swiss Chard is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Florida's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 55 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 245 days to spare even in Florida'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
The zone check says swiss chard survives winter in part of Florida, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Swiss Chard wants 160+ frost-free days; a typical Florida site sees ~320 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Swiss Chard needs ~700 GDD (base 50°F) to ripen. The state median runs ~7743 GDD (from PRISM 1991-2020 climate normals), so Florida'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
Swiss Chard likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across Florida's sandy and muck (everglades) — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 7 — worth knowing before you decide whether a Florida soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Florida site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
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. Florida soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant swiss chard 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 swiss chard goes in. What follows is Florida’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 Florida — and how to grow with it.
We checked the federal record across Florida — 76,189 documented sites across 7 of the 9 source types we track.
The most significant on record: 602 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Florida 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.
Severity Distribution
across Florida
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What Else to Consider for Swiss Chard in Florida
Zone compatibility tells you about winter cold survival — but Florida growers also need to think about:
Sandy soils drain too fast and hold few nutrients — frequent fertilization needed
Humidity drives fungal diseases (powdery mildew, black spot, rust)
Hurricane season (June-November) can destroy plantings
Nematodes are a serious pest in sandy FL soils
What to actually do about these — and the constraints that apply to every Florida grower, not just swiss chard — is covered on the Florida growing guide.
Timing shifts within Florida
Swiss Chard needs about 160 days of frost-free season to complete its cycle. Even Holmes County — Florida’s shortest season at 281 frost-free days — clears that by 121 days, so season length isn’t the constraint anywhere in Florida. What varies is your own parcel.
Across Florida’s 67 counties the frost-free season runs from 281 days in Holmes County to 365 days in Sarasota County — a spread of 84 days, which is why a single statewide planting date misleads. The median Florida county sees 320 frost-free days, leaving swiss chard about 160 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"). Swiss Chard's 160-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Florida Cooperative Extension
For Florida-specific cultivar recommendations, planting calendars, and pest pressure for swiss chard, the canonical source is UF/IFAS Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Swiss Chard in Florida
When can I plant Swiss Chard in Florida?
Florida's last spring hard freeze (28°F) clears between Jan 25 and Feb 10, and the first fall hard freeze lands between Dec 7 and Dec 18 (NOAA Regional Climate Centers ACIS, 1991-2020). Swiss Chard is frost-tender — its killing temperature is 32°F (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
Can Swiss Chard mature before first frost in Florida?
Yes — Swiss Chard matures in 55 days (Growable Ground Plant Database), and Florida's dependable hard-freeze-free window runs 300 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 245 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 Swiss Chard grown in across Florida?
Florida spans USDA hardiness zones 8b-12a (USDA ARS PHZM 2023). Swiss Chard 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 Florida site have?
A typical Florida site sees ~320 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Swiss Chard needs 160+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
How should I amend the soil for Swiss Chard in Florida?
Swiss Chard prefers pH 5.5-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Florida soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Swiss Chard actually grow on my specific land in Florida?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores swiss chard 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 Florida
State-level data is a sketch. Your Growable Ground report scores swiss chard against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Florida swiss chard averages can't show:
We read public map data around Florida — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Florida swiss chard average
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Growing guides for swiss chard
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