Castleford 2 N, ID Frost Dates & Growing Season

The two dates every Castleford 2 N garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 17
~50% chance of frost after
First fall frost
Sep 29
~50% chance of frost before
Growing season
135 days
frost-free stretch
USDA zone
≈ 5b
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 30 May 17 Jun 5
First fall frost Oct 15 Sep 29 Sep 11
Hard freeze (28°F), median last Apr 30 · first Oct 13

Computed from NOAA 1991–2020 climate normals at the CASTLEFORD 2 N station. "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Castleford 2 N

Computed from Castleford 2 N's own frost dates. Click any crop for the full zone-5 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Mar 22 – Apr 5 May 24 – May 31
🫑 Peppers Mar 8 – Mar 22 May 31 – Jun 7
🥬 Lettuce Apr 5 – Apr 19 Apr 19 – May 3 Apr 19 – May 17
🫛 Peas Apr 5 – Apr 19
🥕 Carrots Apr 26 – May 17
🥦 Broccoli Mar 29 – Apr 12 Apr 26 – May 10
🥬 Kale Apr 5 – Apr 19 Apr 19 – May 3 Apr 19 – May 3
🥒 Cucumbers Apr 19 – Apr 26 May 24 – May 31 May 24 – May 31
🥒 Zucchini Apr 19 – Apr 26 May 24 – May 31 May 24 – May 31
🫘 Green Beans (Bush) May 24 – May 31
🌽 Sweet Corn May 24 – May 31
🌿 Basil Apr 5 – Apr 19 May 24 – May 31 May 31 – Jun 7
🧄 Garlic Fall: Aug 18 – Sep 15

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Castleford 2 N's dates automatically after a lookup.

Reading the season in Castleford 2 N

At about 135 frost-free days, Castleford 2 N rewards efficiency: start warm-season crops indoors, favor short-season varieties, and lean on cold-tolerant crops — peas, kale, roots — that shrug off the shoulder-season frosts on either end.

Frequently asked questions

When is the last frost in Castleford 2 N, ID?

The average last spring frost in Castleford 2 N is around May 17, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Castleford 2 N, ID?

The average first fall frost in Castleford 2 N arrives around Sep 29. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Castleford 2 N?

About 135 frost-free days on average, from May 17 to Sep 29. That favors short-season varieties and transplants for warm-season crops, with cool-season vegetables doing the heavy lifting in spring and fall.

What USDA zone is Castleford 2 N in?

USDA zone 5b on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.