Tall Timber, Colorado, sits in USDA hardiness zone 6a — 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, blackberry, california poppy, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Tall Timber, 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 Tall Timber 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 Tall Timber — soil, climate, flood, and parcel records. How we handle your address.
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Tall Timber — the short answer
Tall Timber, Colorado: USDA zone 6a, about 168 days between hard freezes, across 367 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 14
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~168
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 367 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 6a is Tall Timber's average, not your lot's — a low corner or a tree line moves it. Against Tall Timber's 168-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Tall Timber
Each reading below is measured for Tall Timber itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredTall Timber runs about 168 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
MeasuredTall Timber sits in USDA hardiness zone 6a.
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 Tall Timber is in
Tall Timber sits in the Southern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Tall Timber's own centroid rather than borrowed from Boulder County.
What Grows in Tall Timber
Every plant below cleared Tall Timber's own zone 6a and its 168-day season. Each card opens that plant's Colorado profile. How we score.
Is it too late to plant in Tall Timber?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 14 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Tall Timber
Closest first, within ~10 miles of Tall Timber. Listing isn't leaking, and distance isn't exposure.
- SB00107133BACB SITE 004Nitrate · 1100 ft
- SB00107128CCBC SITE 003Nitrate · 2100 ft
- SB00107133BDDA SITE 002Nitrate · 2300 ft
- SC00407120CABANitrate · 0.7 mi
- PORE WATER AT 06727000Nitrate · 1.2 mi
- Poormans ReliefMining · 1.2 mi
- SB00107132CDBA SITE 011Nitrate · 1.2 mi
- SB00107127DBCA SITE C51Nitrate · 1.3 mi
- SB00107127DBCD SITE C55Nitrate · 1.3 mi
- Sylvanite TunnelMining · 1.5 mi
- SB00107132CCCB SITE 015Nitrate · 1.6 mi
- Alaska TunnelMining · 1.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Tall Timber'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 Tall Timber.
Sources Checked
within ~10 miles of Tall Timber
Severity Distribution
within ~10 miles of Tall Timber
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Tall Timber, two things run higher than the national average within ~10 miles of Tall Timber — Mining (97 sites) and Superfund (14 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Tall Timber
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 Tall Timber average
Your land is one point inside Tall Timber
Everything above resolves to Tall Timber as a whole — one PHZM band and one 28°F frost record, read across 367 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 Tall Timber Average
Tall Timber Average
- ●USDA Zones 6a, averaged across Tall Timber
- ●One soil character for all of Tall Timber
- ●Frost dates read at Tall Timber's scale: Apr 29 to Oct 14
YOUR Parcel
- ✓Your exact zone, not Tall Timber's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Tall Timber
Pull a site-specific report for your exact address in Tall Timber, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Tall Timber averages can't show:
We read public map data around Tall Timber — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Tall Timber average
How we know this about Tall Timber
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 Tall Timber’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 Tall Timber
When does frost risk typically end in Tall Timber?
The last hard freeze (28°F) in Tall Timber typically lands around Apr 29, 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 20.
When is the first frost in Tall Timber?
The first hard freeze (28°F) in Tall Timber typically arrives around Oct 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 30, so the watching starts about Sep 14 — about 168 days after the spring freeze cleared.
How long is the growing season in Tall Timber?
Measured between 28°F hard freezes, Tall Timber sees about 168 frost-free days — roughly Apr 29 through Oct 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 20 to Sep 30, about 133 days.
Is the soil safe to grow vegetables in Tall Timber?
The federal record around Tall Timber runs heavier than most — 694 documented sites, mostly Underground Storage Tanks entries (213), the nearest Nitrate record about 0.2 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Tall Timber?
From about Sep 14 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 14 (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 14. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Tall Timber's scale — its 6a band and its 168-day season. Your yard writes its own version of Tall Timber'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 Tall Timber’s own scale
6 of the readings below were taken at Tall Timber's own scale — its own ~168-day season between 28°F freezes, the 367 acres it covers and 694 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Tall Timber's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Tall Timber's own 28°F hard-freeze dates, about Apr 29 and Oct 14 and the ~168-day span between themNOAA 1991–2020 Climate Normals
- 694 documented contamination sites on the federal record near Tall Timber, the closest Nitrate record about 0.2 miles out from the town centreFederal environmental registers
- Tall Timber's boundary and the 367 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~168-day seasonGrowable Ground crop-matching engine
- The ecoregion at Tall Timber's own centroid, the Southern RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Tall Timber's 367 acres read through its county's SSURGO summaryfrom Boulder County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Boulder 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 Boulder County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Tall Timber's 367 acreswhy one lot differs from the next →
- Which side of Tall Timber you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 367 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.2 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 Tall Timber-wide figureread your own land →
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