When to plant watermelons in Knoxville: 4 May – 3 August

In Knoxville, watermelon: sow for seedlings from 16 March to 6 July; plant into a greenhouse from 13 April to 3 August; plant out into open ground from 4 May to 3 August. For plants and seeds, the places nearby include Mayo Garden Center (garden centre, 6 km) and Kirby Plants (garden centre, 15 km); addresses and opening hours are below.

Watermelon in Knoxville: soil, season and weather

In Knoxville the soil, not frost, sets the date: the last frost is over around 29 March, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 4 May, 36 days later.

Last spring frost	29 March
Top 7 cm of soil at 18 °C	4 May, 36 days after the last frost
Into an unheated greenhouse	13 April – 3 August; April outside: 9 °C at night, 20.8 °C by day; card 18–35 °C
First autumn frost	12 November, 192 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	2 July – 1 October
Days left for picking	133
Daylight	12:45 on 6 April, 13:44 on 4 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 8 rainy days

The same dates in Knoxville hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.

Watermelon in Knoxville: care after planting

Planted on 4 May: in the first weeks water every 5 days.

Feeding, by the card’s schedule from that day:

4 May — feed: balanced (NPK)

Pests and diseases of watermelon to watch for:

Dates count from the first planting day of the window above; a later planting moves them by as many days.

Weather in Knoxville during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 31.6 °C. Months that stay below 18 °C even by day on average: November (15.7 °C). Nights average below 18 °C in May and September–November (5.1–17.5 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	25.3	14.5	115	13	14:03
June	29.6	18.6	82	12	14:35
July	31.6	21.3	87	14	14:23
August	30.2	20.1	111	14	13:33
September	28.3	17.5	85	9	12:27
October	22.7	11.3	87	7	11:19
November	15.7	5.1	77	8	10:17

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Knoxville, Atlanta is 21 days earlier and Asheville 20 days later.

City	Distance	Date	Difference
Asheville	130 km	24 May – 24 July	20 days later
Chattanooga	156 km	27 April – 3 August	7 days earlier
Greenville	184 km	23 April – 13 August	11 days earlier
Athens (United States)	229 km	17 April – 13 August	17 days earlier
Lexington	231 km	15 May – 29 July	11 days later
Atlanta	249 km	13 April – 13 August	21 days earlier

Where to buy watermelon plants and seeds near Knoxville

Buy plants ready to set out from 4 May to 3 August (from 13 April to 3 August for an unheated greenhouse); seed for raising your own is sown from 16 March to 6 July. Within 15 km of Knoxville OpenStreetMap lists 7 garden centres, 1 plant nursery and 5 markets (collected 20 October 2026).

Seeds of Change Landscaping & Lawn Care — garden centre
4 km
Southern Rail Station — market
1 km
Mayo Garden Center — garden centre
Kingston Pike 4718, 37919 · Mon–Sat 09:00–18:00; Sun 00:00–17:00 · 6 km · mayogardencenters.com
Kirby Plants — garden centre
Oak Ridge Highway 7234, 37931 Knoxville · 15 km · kirbyplants.com

Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

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