Ryan, Iowa, sits in USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Crops well matched to these conditions include cabbage, cranberry, lavender, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Ryan, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Ryan lot. 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 Ryan — soil, climate, flood, and parcel records. How we handle your address.
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Ryan — the short answer
Ryan, Iowa: USDA zone 5a, about 175 days between hard freezes, across 280 acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~175
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 280 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 5a is Ryan's average, not your lot's — a low corner or a tree line moves it. Against Ryan's 175-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Ryan
Each reading below is measured for Ryan itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredRyan runs about 175 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredRyan sits in USDA hardiness zone 5a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Ryan is in
Ryan sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Ryan's own centroid rather than borrowed from Delaware County.
What Grows in Ryan
Every plant below cleared Ryan's own zone 5a and its 175-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Ryan?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 12 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Ryan
Closest first, within ~10 miles of Ryan. Listing isn't leaking, and distance isn't exposure.
- DELAWARE COUNTY ENGINEERUnderground Storage Tanks · 700 ft
- INDEPENDENCE WIND ENERGY LLCBrownfields · 750 ft
- RYAN FAST STOPUnderground Storage Tanks · 1200 ft
- CLEMENS STDUnderground Storage Tanks · 1300 ft
- RYAN MINI MARTUnderground Storage Tanks · 1400 ft
- 087N06W13DBA 02242 1946Ryan 2Nitrate · 1800 ft
- COGGON ELEMENTARYUnderground Storage Tanks · 5.4 mi
- BOB''S DX SERVICEUnderground Storage Tanks · 5.4 mi
- JOHNS GARAGEUnderground Storage Tanks · 5.5 mi
- BUFFALO BAY GRAIN INCUnderground Storage Tanks · 5.6 mi
- CARYL OIL COMPANYUnderground Storage Tanks · 5.6 mi
- CARSON GRAIN & IMPLEMENTUnderground Storage Tanks · 5.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Ryan'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 Ryan.
Total Sites
121
within ~10 miles of Ryan
Risk Level
Moderate
Highest-severity
8 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Ryan
Severity Distribution
within ~10 miles of Ryan
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Ryan, Toxics Release Inventory runs higher than the national average — 8 sites within ~10 miles of Ryan. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Ryan
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 Ryan average
Your land is one point inside Ryan
Everything above resolves to Ryan as a whole — one PHZM band and one 28°F frost record, read across 280 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 city 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 local average.
Your Lot vs the Ryan Average
Ryan Average
- ●USDA Zones 5a, averaged across Ryan
- ●One soil character for all of Ryan
- ●Frost dates read at Ryan's scale: Apr 20 to Oct 12
YOUR Parcel
- ✓Your exact zone, not Ryan's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Ryan
Pull a site-specific report for your exact address in Ryan, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Ryan averages can't show:
We read public map data around Ryan — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Ryan average
How we know this about Ryan
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Ryan’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Ryan
When does frost risk typically end in Ryan?
The last hard freeze (28°F) in Ryan typically lands around Apr 20, 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 May 11.
When is the first frost in Ryan?
The first hard freeze (28°F) in Ryan typically arrives around Oct 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 28, so the watching starts about Sep 12 — about 175 days after the spring freeze cleared.
How long is the growing season in Ryan?
Measured between 28°F hard freezes, Ryan sees about 175 frost-free days — roughly Apr 20 through Oct 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 11 to Sep 28, about 140 days.
Is the soil safe to grow vegetables in Ryan?
The federal record around Ryan shows 121 documented sites, mostly Underground Storage Tanks entries (64), the nearest Underground Storage Tanks record about 0.1 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Ryan?
From about Sep 12 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 12 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Ryan's scale — its 5a band and its 175-day season. Your yard writes its own version of Ryan's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Ryan’s own scale
6 of the readings below were taken at Ryan's own scale — its own ~175-day season between 28°F freezes, the 280 acres it covers and 121 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Ryan's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Ryan's own 28°F hard-freeze dates, about Apr 20 and Oct 12 and the ~175-day span between themNOAA 1991–2020 Climate Normals
- 121 documented contamination sites on the federal record near Ryan, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Ryan's boundary and the 280 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~175-day seasonGrowable Ground crop-matching engine
- The ecoregion at Ryan's own centroid, the Western Corn Belt PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Ryan's 280 acres read through its county's SSURGO summaryfrom Delaware County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Delaware County
- The growing challenges every Iowa grower plans around — written at state scale, so they stay on the state guidefrom Iowa
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Delaware County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Ryan's 280 acreswhy one lot differs from the next →
- Which side of Ryan you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 280 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Ryan-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaRyan sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides