When to plant rhubarb in Knoxville, Tennessee
February 28 – March 14
Transplant outdoors · typical Knoxville yearClimate 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. Transplant rhubarb outdoors 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.
The Knoxville year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to Apr 29
Every method, with its sources
Transplant outdoors
Feb 28 – Mar 14Purdue Extension HO-186-W Table 1 lists rhubarb in the group headed "Hardy (tolerates hard frost)" with the instruction "plant 4-6 weeks before last spring frost (see Figure 1)" and footnotes it as typically vegetatively propagated, so the source's own 4-6 week range is used directly as the window for setting out dormant crowns rather than seed; the University of Minnesota rhubarb guide was re-checked and anchors only indoor seed starting to the last frost, so it supplied no competing crown-planting date to reconcile against. Anchored to the median last spring freeze (Apr 11). Purdue University Extension, Department of Horticulture and Landscape Architecture
Start seeds indoors
Not calculatedRhubarb is planted from crowns or divisions, and although the Minnesota guide does say to start seed indoors six weeks before the last frost, seed-grown plants push the first harvest to the third season and are not the planting path this window times.
Direct-sow outdoors
Not calculatedPurdue Table 1 footnotes rhubarb as typically vegetatively propagated and publishes no separate direct-seeding date for it.
Fall planting
Not calculatedNo source-backed fall planting rule exists for this crop in the registry, so no fall window is calculated.
Variety assumption: A long-lived perennial planted from crowns or divisions: Minnesota advises waiting until the second season before harvesting (the third season if started from seed), with the harvest season running until the end of June.
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.
Crop rule sources (1)
- 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)"