Question 1

When should I plant watermelon in ZIP 80202?

Accepted Answer

In ZIP 80202, the main watermelon target is around May 19, based on the representative Denver frost station and USDA zone 6a.

Question 2

When should I start watermelon seeds indoors in 80202?

Accepted Answer

Start watermelon seeds indoors in ZIP 80202 around Apr 14, about 21 days before the May 5 last-frost estimate.

Question 3

When is the last frost in Denver?

Accepted Answer

Denver (ZIP 80202) has an average last spring frost around May 5, based on the representative Denver frost station.

Question 4

When is the first frost in Denver?

Accepted Answer

Denver (ZIP 80202) has an average first fall frost around Oct 5, leaving about 153 frost-free days.

Question 5

Is this a guaranteed planting date?

Accepted Answer

No. GrowZone uses frost-date estimates, hardiness zones, and crop timing rules for planning. Local microclimates and current weather can shift the right date.

Step	Date	How to use it
Start Indoors	April 14, 2026	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	May 19, 2026	Move hardened-off seedlings outside after the frost-risk window.
Direct Sow	May 19, 2026	Sow seed outside when the crop and soil can handle the window.

Start watermelon seeds indoors around Apr 14

Watermelon dates for Denver, CO