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When to plant in Keystone, FL

USDA Zone 9b

Here are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Keystone, Florida — all computed from Keystone's nearest NOAA weather station.

Keystone's growing season is short at roughly -11 days, so succession planting is limited; lean on transplants over direct sowing for anything slow to mature. In zone 9b, frost is a minor factor for Keystone — most perennials thrive, and annual vegetables can go out early and stay late.

Station · TARPON SPGS SEWAGE PLT · 14.6 km
Last spring frost
January 20
50% chance · 32°F
First fall frost
January 9
50% chance · 32°F
Growing season
-11 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for KeystoneA year-band from January to December for Keystone: Keystone is effectively frost-free at 32°F — no distinct frost season.
Keystone is effectively frost-free at 32°F — no distinct frost season.

Frost probability

TARPON SPGS SEWAGE PLT · 1991–2020

The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Keystone’s own odds, recorded at TARPON SPGS SEWAGE PLT.

Frost-probability curves for KeystoneProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around January 20 and the first fall frost around January 9, where a 32°F freeze is rare enough that there is effectively no distinct frost season.
Last spring frostFirst fall frostbold = 32°F · thin = 28°F / 36°F · dot = 50% date · band = 10–90% window
ThresholdSPRING 10%SPRING 50%SPRING 90%FALL 10%FALL 50%FALL 90%
36°FMar 1Jan 31Jan 1Dec 3Dec 31Jan 27
32°FFeb 14Jan 20Dec 29Dec 16Jan 9Feb 4
28°FFeb 5Jan 15Dec 29Dec 24Jan 13Feb 1

Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.

What to plant now

TODAY · JULY 19

Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.

Add the next planting windows to your calendar (.ics) ↓

Full-year planting calendar

Start indoorsTransplantDirect sowFall sow

Each bar is the exact window to take a planting action in Keystone, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

3 within 25 km · complete 32°F normals

When stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.

TARPON SPGS SEWAGE PLT
Primary
15 km · 2 m elevation
SPRING
Jan 20
FALL
Jan 9
TAMPA INTL AP
20 km · 6 m elevation
SPRING
Jan 20
FALL
Jan 12
ST PETERSBURG INTL AP
25 km · 3 m elevation
SPRING
Jan 17
FALL
Jan 14

Keystone planting FAQ

When is the last spring frost in Keystone, FL?

Plan for the last spring frost in Keystone around January 20 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.

When is the first fall frost in Keystone, FL?

The first fall frost in Keystone typically arrives around January 9 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.

What hardiness zone is Keystone in?

Keystone is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.

How long is the growing season in Keystone?

Keystone has about -11 frost-free days — a short growing season — between the average last spring frost (January 20) and first fall frost (January 9).

When should I plant tomatoes in Keystone?

For Keystone, sow tomatoes indoors about November 25–December 9 and move the seedlings out around January 27, after the last spring frost.

Planting reminders

Never miss a window in Keystone

An email when it’s time to start seeds, transplant, and sow — timed to Keystone’s frost dates. Double opt-in, one-click unsubscribe, no spam.

Nearby cities

8 within reach

Frost dates recorded at TARPON SPGS SEWAGE PLT, 15 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.

Cite this page
BlissGarden. "When to Plant in Keystone, FL — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00088824. Retrieved from https://blissgarden.com/florida/keystone.