Watermelon is grown for its fruit, ready to harvest about 85 days after planting. It's hardy across USDA zones 3 through 11 and handles dry spells once it's established. As a cucurbit (squash, melon, and cucumber), give it a fresh bed each year — away from where its relatives just grew — so the soil-borne pests and diseases of the family never get a foothold.
Zones
3-11
pH Range
5.5-7.5
Sun
Full Sun
Days to Maturity
85
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What Watermelon is
Watermelon reaches around a foot at maturity. It blooms yellow in summer.
How to grow Watermelon
Watermelon grows in USDA zones 3 through 11 and is ready to harvest about 85 days after planting. Watermelon does best in full sun — at least 6 hours of direct sun a day — and soil from pH 5.5 to 7.5, on well-drained ground. It needs around 2,500 growing degree days to mature, which is why climate matters as much as soil.
USDA Zones
3-11
USDA PHZM 2023
Soil pH
5.5 - 7.5
USDA PLANTS Database
Sun
Full Sun
plant_species_v5.csv
Drainage
well (dry spells)
plant_species_v5.csv
Frost Tolerance
59°F
plant_species_v5.csv
Days to Maturity
85 days
Watermelon; both methods viable in MA, transplant for short seasons.
UMass-Veg; OSU-PNW
GDD Required
2500+
plant_species_v5.csv
Mature Height
1 ft
plant_species_v5.csv
Frost-Free Days
0+
plant_species_v5.csv
Start the season right
Plant watermelon in full sun with at least 6 hours of direct sun, once the soil has warmed and frost risk has passed.
Match the soil
Watermelon prefers pH 5.5 to 7.5 (USDA PLANTS Database). A quick soil test from your local Extension lab tells you whether to add lime or sulfur to land in band.
Water steadily
Keep the root zone evenly moist through establishment. A 2–3 inch mulch layer holds moisture without waterlogging.
Harvest at maturity
Watermelon is ready about 85 days after planting (UMass-Veg; OSU-PNW). Pick when the fruit is full-colored and parts easily from the stem.
Good to know
Good news for pet owners — watermelon isn't known to be toxic to dogs or cats. (Source: ASPCA.)
Where Watermelon thrives
On hardiness alone, watermelon grows across most of the country — its range (USDA zones 3 through 11) is unusually wide. Zone is only the starting point, though: the soil pH, drainage, and frost dates on your specific land decide how well it actually does.
Zones 3–11·Where Watermelon growsOpen map →
On USDA hardiness-zone overlap, Watermelon can grow in these states:
See if Watermelon will thrive on your land
Zone averages are a start. Your exact soil pH, drainage, sun exposure, and frost dates shape whether watermelon actually takes — we score it against the real conditions at your address.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Frequently Asked Questions
Can I grow Watermelon in my zone?
Watermelon grows in USDA hardiness zones 3 through 11 (USDA PHZM 2023). Zone is one factor — soil pH, drainage, and frost dates on your specific parcel also shape whether it takes.
How long does Watermelon take to grow?
Watermelon is ready to harvest about 85 days after planting (UMass-Veg; OSU-PNW). Your local frost dates and soil temperature move that window earlier or later.
When should you plant Watermelon?
Most growers plant watermelon after the last spring frost, once the soil has warmed. Your local frost dates set the exact window — a Growable Ground report reads them for your address.
How much sun does Watermelon need?
Watermelon needs full sun — a spot that catches at least 6 hours of direct summer sun a day. In more shade it still grows, but usually gives a smaller, later crop. The catch is that a yard rarely gets even light everywhere — a fence, the house, or one tall tree can quietly take those hours. A Growable Ground report reads the real sun-hours across your land, canopy and buildings included, so you can pick the brightest bed before you plant.
What soil does Watermelon need?
Watermelon prefers soil pH 5.5 to 7.5, on well-drained ground (USDA PLANTS Database). Your report scores your parcel's actual soil against that using USDA SSURGO data.
Is Watermelon safe for pets?
Watermelon is not known to be toxic to dogs or cats based on available data (ASPCA). Always supervise pets around new plantings.