Question 1

When should I plant watermelon in ZIP 85201?

Accepted Answer

In ZIP 85201, the main watermelon target is around Feb 19, based on the representative Phoenix frost station and USDA zone 10a.

Question 2

When should I start watermelon seeds indoors in 85201?

Accepted Answer

Start watermelon seeds indoors in ZIP 85201 around Jan 15, about 21 days before the Feb 5 last-frost estimate.

Question 3

When is the last frost in Mesa?

Accepted Answer

Mesa (ZIP 85201) has an average last spring frost around Feb 5, based on the representative Phoenix frost station.

Question 4

When is the first frost in Mesa?

Accepted Answer

Mesa (ZIP 85201) has an average first fall frost around Dec 15, leaving about 313 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	January 15, 2026	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	February 19, 2026	Move hardened-off seedlings outside after the frost-risk window.
Direct Sow	February 19, 2026	Sow seed outside when the crop and soil can handle the window.

Start watermelon seeds indoors around Jan 15

Watermelon dates for Mesa, AZ