Month-by-month planting calendar

Zones vs frost dates

USDA's 2023 hardiness map is based on the average coldest winter night from 1991 to 2020. It uses 10°F zones split into 5°F halves (a and b). That tells you which perennials survive winter. It does not tell you when to plant.

Your three numbers

For the NOAA station nearest you in distance and elevation, find:

• Last frost, median (LF50): half of years still freeze after this.

• Last frost, 10% (LF10): only 1 year in 10 freezes after this. In these stations it's about 2–3 weeks after the median, sometimes 3.

• First fall frost, median (FF50).

Where to get them:

• the frost-date table further down this lesson

• NOAA's normals tool

• your county extension office

Warm-area caution: in Florida, the Gulf Coast and the low desert, NOAA's dates describe only the years that freeze at all. Phoenix freezes in 17.5% of years and Orlando in 61%.

Cold pockets: low spots and valleys run colder than nearby slopes, and frost can form on plants when the thermometer says 36°F.

Fill in your own dates. The Seed starting lesson has the details.

\* Tender-plant date = 2 weeks after LF50 or the LF10 date, whichever is later. CSU puts very tender crops "2+ weeks after" the average last frost, and the 10% date is the cautious line.

Each calendar uses one real station as its example. If your dates differ, slide the garden tasks by the difference.

Zones 3–4: short season

Example: Fargo, ND (zone 4a)

• Last frost: median May 10, 10% May 23

• First fall frost: median Sep 30

• Season: 143 days

Colder variant: International Falls, MN (zone 3b)

• Last frost: median May 29, 10% Jun 16

• First fall frost: median Sep 13

• Season: 109 days

Cross-check: UMN starts onions in early February, brassicas in early March and tomatoes in early April, and moves warm crops out "mid-to-late May". Maine sets tomatoes out May 25–Jun 20. Both match the Fargo calculation.

Mountain West at zone 3–4 elevations has even later dates:

• Laramie, WY: median Jun 2, 102-day season

• Alamosa, CO: median Jun 7, 98-day season

Zones 5–6: four-season Midwest and Northeast

Example: Des Moines, IA (zone 5b)

• Last frost: median Apr 18, 10% May 2

• First fall frost: median Oct 20

• Season: 184 days

Variant: Albany, NY (zone 6a)

• Last frost: median Apr 27, 10% May 11

• First fall frost: median Oct 15

Mountain West at zone 5–6: Denver's median is May 5 and Billings' May 4, both with 156-day seasons. Montana keys crops to frost directly. Peas go in from 4–6 weeks before the last frost; broccoli from 6 weeks before.

Zones 7–8: long season with a fall garden

Example: St Louis, MO (zone 7a)

• Last frost: median Apr 2, 10% Apr 17

• First fall frost: median Nov 4

• Season: 215 days

Warmer example: Atlanta, GA (zone 8b)

• Last frost: median Mar 15, 10% Apr 4

• First fall frost: median Nov 20

• Season: 252 days

Onions in zones 8+ are short-day types. Johnny's sows them indoors mid-September to mid-October, and Louisiana sets them out Dec 15–Jan 31. The 16-week-before-frost rule doesn't apply there.

Zones 9–10: fall-to-spring gardening

Example: Charleston, SC (zone 9a)

• Last frost: median Mar 7, 10% Mar 27

• First fall frost: median Nov 27

• Season: 266 days

Zone 10: Orlando and Phoenix freeze only in some years (61% and 17.5% of years). Use the extension calendars below.

Bees (Utah State calendar; shift earlier in warm zones)

• Jan–Feb: emergency feeding only if a hive weighs under 50–80 lb, using fondant on a day above 55°F.

• Mar: 1:1 sugar syrup and pollen patty.

• Apr: first full inspection on a day above 55°F.

• May: swarm season. Start mite checks, then check monthly.

• Aug: mites "explode." Make your fall treatment plan and rotate products.

• Sep: 2:1 syrup. Target hive weight 80–100 lb.

• Oct: smallest entrance, mouse guard, wrap hives at high elevation.

• Nov–Dec: don't open hives below 55°F.

• Order packages in late fall or winter for April–May delivery.

• Mite thresholds differ: Utah treats above 5 mites per 300 bees. Mississippi uses 1% in February and 3% May–October. Follow your state's guidance and the product label.

• Northeast:

  • Maine's coast and north run 10–14 days off the central-Maine dates.
  • Philadelphia plants peas and potatoes mid-March and tomatoes mid-May to late June.

• Southeast:

  • South Georgia runs 2–3 weeks earlier in spring than middle Georgia; north Georgia runs 1–3 weeks later.
  • Summer heat and disease make fall the best garden season.

• Midwest:

  • Iowa shifts about 1 week earlier in the south and 1 week later in the north.
  • Cold, wet springs: plant by soil temperature.

• Southwest:

  • The low desert has two seasons, February–April and August–November.
  • Texas splits into Regions I–V, about zones 6 to 9B.
  • Elevation changes everything: Albuquerque's median is Apr 6, El Paso's Mar 2.

• Pacific Northwest:

  • West of the Cascades:
  • cool summers; tomatoes go in once soil passes 70°F
  • winter brassicas transplanted mid-July to early August
  • cover crops by September–October
  • garlic in October
  • East of the Cascades: peas and lettuce go in late April, corn late May.
  • Coastal Astoria's median last frost is Mar 26; Portland's is Mar 13.

• Mountain West:

  • Utah keys crops to each town's frost date: hardy crops as soon as soil can be worked, tender ones 2 weeks after last frost.
  • High valleys have 100-day seasons or less (Laramie, Alamosa).
  • Crested Butte (8,867 ft) can freeze in any month.

Zone 3

Zone 4

Zone 5

Zone 6

Zone 7

Zone 8

Zone 9

Zone 10

Notes

• Zone is not frost date. Zone 8b alone runs from Mar 2 (El Paso) to Apr 8 (Medford) for the median last frost.

• Warm-zone dates are conditional: in Florida, the low desert and the Gulf, NOAA's dates describe only the years that freeze at all; the percentages show how often that is.

• Dates crossing New Year: a spring date in December or a fall date in January means frost is rare and the freeze season wraps around the year.

• High elevation: Crested Butte, CO (8,867 ft) can see 32°F in any month.

• Station zones near a half-zone edge (within about 0.5°F): Billings, Boise, Caribou, Charleston, Burlington, International Falls, Crested Butte.

• Frost dates: your nearest NOAA station's median and 10% dates, or NOAA's normals tool.

• Soil thermometer: for 4-in soil readings at 8 a.m..

• Row covers: medium weight gives up to about 4°F of protection, heavy 4–8°F.

• Low tunnels: fabric, switching to 4–6 mil plastic as weather cools.

• Paper calendar or spreadsheet with the master-calendar rules filled in for your dates.

Costs: none of these sources gave prices. See the individual topic guides.

1. 1

   Planning from your zone instead of your frost dates.

2. 2

   Using the average last frost for tomatoes and peppers. Use the later 10% date.

3. 3

   Starting seeds too early, which gives over-age transplants.

4. 4

   Forgetting the fall garden. Count back from the first frost (days to maturity + 18).

5. 5

   Using northern onion timing in the South, where onions are short-day types sown in fall.

6. 6

   Planting extension-table dates without checking that table's frost assumptions. Utah's table uses Apr 26 for Salt Lake; NOAA's 1991–2020 median is Apr 8.

7. 7

   Grazing frosted sorghum or sudangrass too soon.

8. 8

   Skipping late-summer mite checks.