Question 1

When should I plant watermelon in ZIP 21201?

Accepted Answer

In ZIP 21201, the main watermelon target is around Apr 29, based on the representative Baltimore frost station and USDA zone 7b.

Question 2

When should I start watermelon seeds indoors in 21201?

Accepted Answer

Start watermelon seeds indoors in ZIP 21201 around Mar 25, about 21 days before the Apr 15 last-frost estimate.

Question 3

When is the last frost in Baltimore?

Accepted Answer

Baltimore (ZIP 21201) has an average last spring frost around Apr 15, based on the representative Baltimore frost station.

Question 4

When is the first frost in Baltimore?

Accepted Answer

Baltimore (ZIP 21201) has an average first fall frost around Nov 5, leaving about 204 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	March 25, 2026	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	April 29, 2026	Move hardened-off seedlings outside after the frost-risk window.
Direct Sow	April 29, 2026	Sow seed outside when the crop and soil can handle the window.

Start watermelon seeds indoors around Mar 25

Watermelon dates for Baltimore, MD