Yes — Strong Match
watermelon (zones 3-11) covers every zone Kansas contains (5b-7a), so hardiness is not what limits it anywhere in the state.
Watermelon in Kansas — the short answer
Watermelon in Kansas: hardy in zones 3–11, full sun, against a state median of ~208 frost-free days.
- Plant zones
- 3-11
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Kansas zones
- 5b-7a
- USDA PHZM 2023
- Frost window
- Apr 1 - Apr 12 – Oct 25 - Nov 3
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 177 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 85 days
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Kansas spans zones 5b-7a, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score watermelon against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Kansas is not one climate
A single Kansas answer averages 105 counties whose growing seasons are 54 days apart — from 177 frost-free days in Greeley County to 231 in Crawford County. Which end of that your land sits nearer changes what watermelon can finish before the first hard freeze.
The middle half of 105 counties runs 197–216 days, with a median of 208 days — a 54-day span end to end.
Measured across 105 Kansas counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where in Kansas Fits Best
Even within Kansas's zones 5b-7a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for watermelon (USDA PHZM 2023):
Zone Comparison
Watermelon Needs
- USDA Zones: 3-11
- Sun: Full Sun
- Mature size: 1 ft tall
- Picking window: ~21 days of harvest
- Drought tolerance: High
Kansas Has
- USDA Zones: 5b-7a
- Last Hard Freeze (28°F): Apr 1 - Apr 12
- First Hard Freeze (28°F): Oct 25 - Nov 3
- Annual Rainfall: 16-42 inches
- Common Soils: Prairie loam, Silt loam, Clay
Plant Zone Range (zones 3-11)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Watermelon in Kansas
The frost window
Across Kansas, the last spring hard freeze (28°F) clears between Apr 1 and Apr 12, and the first fall hard freeze lands between Oct 25 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 196-day window you can count on — up to 216 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
When to start the seed
Those dates are when watermelon goes out, not when it starts. It is sown under cover about 3 weeks ahead, so counting back from Kansas's late-side last freeze of Apr 12 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Days to maturity vs. the window
At 85 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 111 days to spare even in Kansas's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Greeley County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says watermelon survives winter here. Whether the season is long enough — and warm enough — is a different question.
Days to maturity
Watermelon matures in ~85 days (Growable Ground Plant Database). A typical Kansas site has ~208 frost-free days, so plenty of room for a second succession.
Growing degree days
Watermelon needs ~2500 GDD (base 50°F) to ripen. The state median runs ~3821 GDD (from PRISM 1991-2020 climate normals), so Kansas's typical season clears that easily.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Watermelon likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across Kansas's prairie loam and silt loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 7 — worth knowing before you decide whether a Kansas soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Kansas site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Kansas's soils run mostly silt loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Watermelon needs about 59 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how watermelon performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Kansas soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant watermelon for food
Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before watermelon goes in. What follows is Kansas’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.
Safe to Grow Here?
What the federal record shows across Kansas — and how to grow with it.
We checked the federal record across Kansas — 33,298 documented sites across 8 of the 9 source types we track.
The most significant on record: 146 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Kansas carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources Checked
across Kansas
Severity Distribution
across Kansas
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Kansas, two things run higher than the national average across Kansas — Nitrate (15,878 sites) and CAFO (485 sites). That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What Else to Consider for Watermelon in Kansas
Zone compatibility tells you about winter cold survival — but Kansas growers also need to think about:
Low rainfall in western KS requires irrigation
Extreme wind and hail during severe storm season
Hot dry summers with 100F+ days
Growing watermelon here specifically
Watermelon sends deep roots and rates to zones 3–11, but much of Kansas sits on slow-draining, restrictive ground (SSURGO hydrologic group D) that forks and stunts them.
Loosen a deep, stone-free bed for watermelon and break any compacted or hardpan layer before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Kansas grower, not just watermelon — is covered on the Kansas growing guide.
Timing shifts within Kansas
Kansas isn't one climate. In Greeley County, the last hard freeze (28°F) holds until about Apr 23 — roughly 18 days later than the recorded state median — so plant watermelon to your county's window, not the statewide date.
Watermelon needs about 85 days of frost-free season from planting to harvest. Even Greeley County — Kansas’s shortest season at 177 frost-free days — clears that by 92 days, so season length isn’t the constraint anywhere in Kansas. What varies is your own parcel.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Watermelon's 85-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.
Kansas Cooperative Extension
For Kansas-specific cultivar recommendations, planting calendars, and pest pressure for watermelon, the canonical source is K-State Research and Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Watermelon native to Kansas?
No — the USDA PLANTS Database lists Watermelon as introduced rather than native in the Lower 48, so it is not part of Kansas's native flora. It grows here as a garden plant; pairing it with a few Kansas natives keeps local pollinators fed too.
Looking for plants that belong here? The Kansas growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
What pests threaten watermelon in Kansas?
Squash bug is documented in Kansas and will find watermelon, but it is manageable here. What an experienced grower watches for, and does:
Squash bug
Worth watchingSquash bugs will feed on any cucurbit — the University of Illinois says all members of the family — but they prefer squash and pumpkins, so a cucumber or melon planting is usually the second thing they find, not the first.
What to do: Let the squash rows do the scouting: check them first, and when egg clusters show up there, start checking leaf undersides here too. Crush eggs on sight and keep debris cleared.
Here: In Kansas that second clean-up lands around Oct 25 - Nov 3, when the first 28°F freeze typically ends the watermelon — pulling the vines then is what strips the overwintering shelter, and leaving them is what stocks next season.
Documented range: the United States · University of Illinois IPM, University of Minnesota Extension
Only pests whose documented range and host relationship both trace to a primary source appear here — so a quiet section means we have nothing sourced to tell you, not that your garden is pest-free.
Common Questions About Growing Watermelon in Kansas
When can I plant Watermelon in Kansas?
Kansas's last spring hard freeze (28°F) clears between Apr 1 and Apr 12, and the first fall hard freeze lands between Oct 25 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Watermelon mature before first frost in Kansas?
Yes — Watermelon matures in 85 days (Growable Ground Plant Database), and Kansas's dependable hard-freeze-free window runs 196 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 111 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Watermelon grown in across Kansas?
Kansas spans USDA hardiness zones 5b-7a (USDA ARS PHZM 2023). Watermelon carries a range of zones 3-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Kansas site have?
A typical Kansas site sees ~208 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Watermelon should be matched against that window, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Greeley, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Watermelon native to Kansas?
No — the USDA PLANTS Database lists Watermelon as introduced rather than native in the Lower 48, so it is not part of Kansas's native flora. It grows here as a garden plant; pairing it with a few Kansas natives keeps local pollinators fed too.
How should I amend the soil for Watermelon in Kansas?
Watermelon prefers pH 5.5-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Kansas soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Watermelon actually grow on my specific land in Kansas?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores watermelon against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Kansas
State-level data is a sketch. Your Growable Ground report scores watermelon against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Kansas watermelon averages can't show:
We read public map data around Kansas — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kansas watermelon average
Explore More
Growing guides for watermelon
Explore Kansas county by county
Kansas carries 105 counties with their own USDA zone — a sample of the growing pages for watermelon there:
Where else watermelon grows
Watermelon's zone band crosses state lines — these are the states closest to Kansas in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Kansas
Kansas has a growing page for 893 plants — a rotating sample of the rest of the shelf.
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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