Unlikely — Zone Mismatch
caladium (zones 9-11) does not overlap with Pennsylvania's zone range (5b-8a). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
Caladium is hardy to zone 9, and the warmest ground in Pennsylvania is zone 7 — 2 zones short. Planted in open ground it will not survive a Pennsylvania winter. To grow it here, grow caladium under glass — a greenhouse is the only lift this wide the engine models.
A greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 9-11 (plant) against 5-7 (Pennsylvania). 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.
Pennsylvania spans zones 5b-8a, 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 caladium against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Zone Comparison
Caladium Needs
- USDA Zones: 9-11
- Frost-Free Days: 180+
- Sun: Full Sun
- Mature size: 2 ft tall
- Picking window: ~90 days of harvest
- Drought tolerance: Low
Pennsylvania Has
- USDA Zones: 5b-8a
- Last Hard Freeze (28°F): Apr 6 - Apr 24
- First Hard Freeze (28°F): Oct 25 - Nov 3
- Annual Rainfall: 36-48 inches
- Common Soils: Silt loam, Shale-derived, Limestone-derived
Plant Zone Range (zones 9-11)
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 Caladium in Pennsylvania
The frost window
Across Pennsylvania, the last spring hard freeze (28°F) clears between Apr 6 and Apr 24, and the first fall hard freeze lands between Oct 25 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 184-day window you can count on — up to 211 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
Caladium is frost-tender — its listed minimum temperature is 50°F (USDA PLANTS Database) — 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.
Timing tuned to sub-state frost dates — Potter 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 caladium does not survive a Pennsylvania 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 Pennsylvania under protection.
Frost-free days
Caladium wants 180+ frost-free days; a typical Pennsylvania site sees ~197 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a tight window — use transplants and pick early-maturing cultivars.
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
Caladium tolerates a wide pH range (pH 4.3-8.2) — 3.9 units, acid ground through alkaline — so soil acidity is rarely what limits it in Pennsylvania. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. 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 Pennsylvania soil test result is a problem or just a number. Drainage matters: this plant wants poorly (saturated >50% of year), well (dry spells). If your Pennsylvania site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 14.1% of Pennsylvania as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Caladium has low drought tolerance, so it is the fast-draining end that will cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Pennsylvania soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Caladium in Pennsylvania — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 9-11 (USDA PLANTS Database)
- State Zones: 5b-8a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 6 - Apr 24 to Oct 25 - Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Caladium in Pennsylvania
Zone compatibility tells you about winter cold survival — but Pennsylvania growers also need to think about:
Rocky shale soils in the ridge-and-valley region
Short mountain seasons in the Poconos and Alleghenies
Deer pressure is among the highest in the US
Growing caladium here specifically
Caladium needs sharp drainage and sends medium roots hardy to about 50°F; in Pennsylvania, about 14.1% of soils are poorly-drained (SSURGO), and standing water is what actually kills it.
Build caladium up on a coarse, free-draining mound so its roots never sit in saturated soil. How to handle it →
What to actually do about these — and the constraints that apply to every Pennsylvania grower, not just caladium — is covered on the Pennsylvania growing guide.
Timing shifts within Pennsylvania
Pennsylvania isn't one climate. In Potter County, the last hard freeze (28°F) holds until about May 5 — roughly 21 days later than the recorded state median — so plant caladium to your county's window, not the statewide date.
Caladium needs about 180 days of frost-free season to complete its cycle. 52 of Pennsylvania’s 67 counties give it that outright. The tightest that does is Butler County at 181 frost-free days — 1 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
Across Pennsylvania’s 67 counties the frost-free season runs from 160 days in Potter County to 250 days in Philadelphia County — a spread of 90 days, which is why a single statewide planting date misleads. The median Pennsylvania county sees 197 frost-free days, leaving caladium about 17 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"). Caladium's 180-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Good to Know Before You Plant Caladium
Caladium is listed as toxic to dogs, cats (all) at a moderate level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear. Worth knowing for placement: in Pennsylvania this is a one-season plant and the first hard freeze (Oct 25 - Nov 3) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Caladium Varieties for Pennsylvania
Pennsylvania publishes no state variety trial for caladium, so we won't invent a "best for Pennsylvania" list. Choose types rated to your USDA hardiness zone (5b-8a), and confirm winter survival and drainage against your own parcel.
Pennsylvania Cooperative Extension
For Pennsylvania-specific cultivar recommendations, planting calendars, and pest pressure for caladium, the canonical source is Penn State Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Caladium in Pennsylvania
When can I plant Caladium in Pennsylvania?
Pennsylvania's last spring hard freeze (28°F) clears between Apr 6 and Apr 24, and the first fall hard freeze lands between Oct 25 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). Caladium is frost-tender — its listed minimum temperature is 50°F (USDA PLANTS Database) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
What hardiness zone is Caladium grown in across Pennsylvania?
Pennsylvania spans USDA hardiness zones 5b-8a (USDA ARS PHZM 2023). Caladium carries a range of zones 9-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Pennsylvania site have?
A typical Pennsylvania site sees ~197 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Caladium needs 180+ 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 Potter, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for Caladium in Pennsylvania?
Caladium tolerates pH 4.3-8.2 and poorly (saturated >50% of year), well (dry spells) drainage (FAO ECOCROP). That is a 3.9-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Pennsylvania site — amend for drainage and organic matter first.
Will Caladium actually grow on my specific land in Pennsylvania?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores caladium 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 Pennsylvania
State-level data is a sketch. Your Growable Ground report scores caladium against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Pennsylvania caladium averages can't show:
We read public map data around Pennsylvania — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Pennsylvania caladium average
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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