Simla, Colorado, sits in USDA hardiness zone 5b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
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 Simla, 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 Simla 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 Simla — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Simla — the short answer
Simla, Colorado: USDA zone 5b, about 157 days between hard freezes, across 417 acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~157
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 417 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 5b is Simla's average, not your lot's — a low corner or a tree line moves it. Against Simla's 157-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Simla
Each reading below is measured for Simla itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSimla runs about 157 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
MeasuredSimla sits in USDA hardiness zone 5b.
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 Simla is in
Simla sits in the Southwestern Tablelands — EPA Level III, inside the wider Great Plains. That is read at Simla's own centroid rather than borrowed from Elbert County.
What Grows in Simla
Every plant below cleared Simla's own zone 5b and its 157-day season. Each card opens that plant's Colorado profile. How we score.
Is it too late to plant in Simla?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 6; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 8 — 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 Simla
Closest first, within ~10 miles of Simla. Listing isn't leaking, and distance isn't exposure.
- GOOD SAMARITAN SOCIETY - SIMLABrownfields · 650 ft
- BIG SANDY SCHOOL DIST 100-JBrownfields · 700 ft
- Happy TimezUnderground Storage Tanks · 750 ft
- M T Small EnginesUnderground Storage Tanks · 1200 ft
- Elbert County Road & Bridge DeptUnderground Storage Tanks · 1600 ft
- SC01106003DAC LFHMAS08Nitrate · 1.6 mi
- SB00205931DC1Nitrate · 4.6 mi
- OIT Simla #212Underground Storage Tanks · 5.9 mi
- CDOT MathesonUnderground Storage Tanks · 6.3 mi
- SC01106128CAA ARAPMAS26Nitrate · 9.6 mi
Measured from Simla'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 Simla.
Severity Distribution
within ~10 miles of Simla
Highest-Severity Sites
Know Before You Grow
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •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.
Check your specific parcel in Simla
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 Simla average
Your land is one point inside Simla
Everything above resolves to Simla as a whole — one PHZM band and one 28°F frost record, read across 417 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 town 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 Simla Average
Simla Average
- ●USDA Zones 5b, averaged across Simla
- ●One soil character for all of Simla
- ●Frost dates read at Simla's scale: May 4 to Oct 8
YOUR Parcel
- ✓Your exact zone, not Simla's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Simla
Pull a site-specific report for your exact address in Simla, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Simla averages can't show:
We read public map data around Simla — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Simla average
How we know this about Simla
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Simla’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 town grain anywhere on this page — there is no town-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 Simla
When does frost risk typically end in Simla?
The last hard freeze (28°F) in Simla typically lands around May 4, 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 25.
When is the first frost in Simla?
The first hard freeze (28°F) in Simla typically arrives around Oct 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 24, so the watching starts about Sep 8 — about 157 days after the spring freeze cleared.
How long is the growing season in Simla?
Measured between 28°F hard freezes, Simla sees about 157 frost-free days — roughly May 4 through Oct 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 25 to Sep 24, about 122 days.
Is the soil safe to grow vegetables in Simla?
The federal record around Simla is light — 13 documented sites across the 9 federal source types we checked, mostly Nitrate entries (6), the nearest Brownfields record about 0.1 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Simla?
From about Sep 8 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 8 (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 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Simla's scale — its 5b band and its 157-day season. Your yard writes its own version of Simla'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 Simla’s own scale
6 of the readings below were taken at Simla's own scale — its own ~157-day season between 28°F freezes, the 417 acres it covers and 13 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Simla's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Simla's own 28°F hard-freeze dates, about May 4 and Oct 8 and the ~157-day span between themNOAA 1991–2020 Climate Normals
- 13 documented contamination sites on the federal record near Simla, the closest Brownfields record about 0.1 miles out from the town centreFederal environmental registers
- Simla's boundary and the 417 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~157-day seasonGrowable Ground crop-matching engine
- The ecoregion at Simla's own centroid, the Southwestern TablelandsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Simla's 417 acres read through its county's SSURGO summaryfrom Elbert County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Elbert County
- The growing challenges every Colorado grower plans around — written at state scale, so they stay on the state guidefrom Colorado
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Elbert County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Simla's 417 acreswhy one lot differs from the next →
- Which side of Simla you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 417 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Simla-wide figureread your own land →
More in Colorado
Wider growing context
What grows across ColoradoSimla sits outside our named growing regions, so Colorado as a whole is its closest context here.