When to plant watermelon in Salt Lake City, Utah
April 14 – April 28
Transplant outdoors · typical Salt Lake City yearClimate basis: NOAA station Salt Lake Triad Ctr, UT (USC00427606), 1 mi (2 km) from downtown Salt Lake City (ZCTA 84111 centroid), elevation 4280 ft, on the 1991–2020 climate normals. Transplant watermelon outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (March 31). One year in ten still freezes after April 19.
The Salt Lake City year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to Apr 19
Every method, with its sources
Start seeds indoors
Mar 17 – Mar 24Iowa State: start seeds indoors 3–4 weeks before the anticipated outdoor planting date (Missouri G6570: 3–5 weeks). Anchored to the median last spring freeze (Mar 31). Iowa State University Extension and Outreach · University of Missouri Extension
Transplant outdoors
Apr 14 – Apr 28Same outdoor timing as direct seeding, using pot-grown transplants. Anchored to the median last spring freeze (Mar 31). Iowa State University Extension and Outreach · Purdue University Extension
Direct-sow outdoors
Apr 14 – Apr 28Iowa State: plant after the danger of frost is past once soil reaches 60–70°F; Purdue's very-tender melon class (at least two weeks after frost) is the conservative reading used. Anchored to the median last spring freeze (Mar 31). Iowa State University Extension and Outreach · Purdue University Extension
Variety assumption: Assumes an average variety (about 80–90 days from seed).
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 (3)
- Iowa State University Extension and Outreach: Growing Watermelon in the Home Garden (accessed 2026-07-24)"Plant melons after the danger of frost is past and soil temperatures have warmed to 60 to 70°F." "Start seeds indoors 3 to 4 weeks before the anticipated outdoor planting date."
- University of Missouri Extension: Starting Plants Indoors from Seeds (G6570) (accessed 2026-07-24)Weeks needed to grow vegetable transplants indoors (Table 2).
- Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.