When to plant scallions (green onions) in Knoxville, Tennessee

March 14 – March 28

Direct-sow outdoors · typical Knoxville year

Climate basis: NOAA station Knoxville Exp Stn, TN (USC00404946), 5 mi (8 km) from downtown Knoxville (ZCTA 37902 centroid), elevation 830 ft, on the 1991–2020 climate normals. Direct-sow scallions (green onions) from approximately the dates above, anchored to the median last spring 32°F freeze (April 11). One year in ten still freezes after April 29.

Last spring freezeApril 111-in-10 after Apr 29

First fall freezeOctober 281-in-10 before Oct 13

Frost-free season≈ 198 daysmedian at 32°F

Hard freeze, 28°Mar 31 – Nov 6kills even hardy greens

USDA zone7b5 to 10°F winter low — not frost timing

The Knoxville year

Direct-sow outdoorsMar 14 – Mar 28

Fall plantingSep 2 – Sep 30

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to Apr 29

Scallions (Green Onions) in Knoxville · freeze context from Knoxville Exp Stn, TN, 1991–2020 normals.

Every method, with its sources

Direct-sow outdoors

Mar 14 – Mar 28

Colorado State University Extension's CMG GardenNotes #720 groups onions with the Hardy Vegetables that may go in "As early as 2-4 weeks before the date of the average last spring frost," and the same publication's Table 1 Cool Season Vegetable Planting Guide lists "Onions, green" among those cool-season crops, so the 2-to-4-week pre-frost span is used directly; no other extension source located gave a later-starting green-onion spring rule, so nothing needed reconciling. Anchored to the median last spring freeze (Apr 11). Colorado State University Extension (Colorado Master Gardener)

Fall planting

Sep 2 – Sep 30

Purdue Extension HO-186-W Table 2 lists green onion among cool-season plants for late-summer or fall planting to be planted "at least 4-8 weeks before first fall frost," which encodes as a window running from eight weeks down to four weeks ahead of the first fall freeze; it was the only extension source found anchoring a green-onion fall sowing to frost, so it stands unreconciled. Anchored to the median first fall freeze (Oct 28). Purdue University Extension, Department of Horticulture and Landscape Architecture

Variety assumption: Assumes non-bulbing bunching types or true onions pulled young; Colorado State's Table 1 gives 60 typical days to harvest for "Onions, green" versus 110 for dry onions, and this entry encodes only the green-onion crop.

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:

Crop rule sources (2)

Colorado State University Extension (Colorado Master Gardener): CMG GardenNotes #720: Vegetable Planting Guide (accessed 2026-07-25)
"Hardy Vegetables ... Crops: broccoli, cabbage, kohlrabi, onions, lettuce, peas, radish, spinach, turnips"
Purdue University Extension, Department of Horticulture and Landscape Architecture: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-25)
"Table 2. Cool season plants for late-summer or fall planting (plant at least 4-8* weeks before first fall frost) (See Figure 2)"

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