When to plant watermelons in Maryland
Maryland’s average last spring frost is April 14, and the first fall frost typically arrives around October 20 — about 189 frost-free days (USDA zones 5b, 6a, 6b, 7a, 7b, 8a). Watermelon needs 70–100 days to mature, which fits comfortably within Maryland's growing season.
Maryland covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant watermelons in Maryland: the short answer
For a spring planting, plant out Apr 21 – May 8, with seeds started indoors Mar 17 – Mar 31. Wait until the soil is at least 70°F and frost is over.
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow watermelons in Maryland, step by step
- Start seeds indoors (Mar 17 – Mar 31). Sow seeds 1 inch deep in seed-starting mix under bright light. They take 4-10 days to sprout, fastest in soil around 85°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. They need at least six to eight hours of direct sun a day and loose soil at least 24 inches deep, with a pH between 5.5 and 6.8. Dig in compost before planting.
- Plant out (Apr 21 – May 8). Space plants about 36 inches apart in rows 72 inches apart. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: striped cucumber beetle, aphids, squash vine borer. Diseases and disorders: anthracnose, fusarium wilt, powdery mildew, gummy stem blight.
- Harvest (from about Jul 7 – Aug 6). Watermelon takes 70-100 days to reach harvest. Longest-season cucurbit here - icebox varieties (70-75 days) are the realistic choice north of the mid-Atlantic. Ripe when the curly tendril nearest the fruit is brown and dry and the ground spot is buttery yellow.
Figures come from our crop data; dates use Maryland’s average frost dates. More in the full watermelon growing guide.
Watermelon planting dates by USDA zone in Maryland
Maryland spans USDA zones 5b, 6a, 6b, 7a, 7b, 8a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the watermelon dates shift with them.
When to plant watermelons in nearby states
| State | Last frost | Plant out |
|---|---|---|
| Maryland (this page) | April 14 | Apr 21 – May 8 |
| New Jersey | April 20 | Apr 27 – May 14 |
| Pennsylvania | May 1 | May 8 – May 25 |
| Delaware | April 14 | Apr 21 – May 8 |
| District of Columbia | April 10 | Apr 17 – May 4 |
| Virginia | April 15 | Apr 22 – May 9 |
| West Virginia | May 5 | May 12 – May 29 |
Questions gardeners in Maryland ask
When is the best time to plant watermelons in Maryland?
Plant watermelon transplants outdoors in Maryland between April 21 and May 8. That timing is set by Maryland's average last spring frost of April 14; Maryland spans several climates, so cooler and higher parts of the state run later.
When should I start watermelon seeds indoors in Maryland?
Start seeds indoors between March 17 and March 31, about 3 weeks before the last frost, so the seedlings are ready to plant out from April 21.
What is the latest I can plant watermelons in Maryland?
About August 11. Watermelons need at least 70 days to mature, and frost around October 20 ends the season, so later plantings risk being cut short.
When will watermelons planted in Maryland be ready to harvest?
Planted on time, watermelons are usually ready from about July 7 to August 6, 70-100 days after planting.
When is the last frost in Maryland?
On average around April 14, with the first fall frost around October 20 - about 189 frost-free days. Your town may differ by two weeks or more.