When to plant watermelons in Baltimore: 5 May – 13 August

In Baltimore, watermelon: sow for seedlings from 17 March to 16 July; plant into a greenhouse from 14 April to 13 August; plant out into open ground from 5 May to 13 August. For plants and seeds, the places nearby include Fruitland (farm shop, 11 km) and George's Farm Market (farm shop, 11 km); addresses and opening hours are below.

Watermelon in Baltimore: soil, season and weather

In Baltimore the soil, not frost, sets the date: the last frost is over around 31 March, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 5 May, 35 days later.

Last spring frost	31 March
Top 7 cm of soil at 18 °C	5 May, 35 days after the last frost
Into an unheated greenhouse	14 April – 13 August; April outside: 8.6 °C at night, 17.5 °C by day; card 18–35 °C
First autumn frost	22 November, 201 days after the start
Days in the bed to the first harvest (card)	59
First harvest, if planted in this window	3 July – 11 October
Days left for picking	142
Daylight	12:53 on 7 April, 13:59 on 5 May
Watering outdoors when fruiting (card)	every 5 days; the driest month, November, has 8 rainy days

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

Watermelon in Baltimore: care after planting

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

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

5 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 Baltimore during the watermelon season

No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 30 °C. Months that stay below 18 °C even by day on average: November (13.1 °C). Nights average below 18 °C in May (13.9 °C), October (12.4 °C) and November (5.6 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	21.9	13.9	163	14	14:19
June	27.3	19.2	139	13	14:55
July	30	22.5	191	16	14:41
August	28.5	21.4	162	13	13:44
September	25.5	18.4	146	11	12:29
October	19.7	12.4	102	9	11:13
November	13.1	5.6	88	8	10:03

ERA5 2016–2025, Open-Meteo

Watermelon in nearby cities

Around Baltimore, Washington, D.C. is 1 day earlier and Harrisburg 20 days later.

City	Distance	Date	Difference
Annapolis	37 km	8 May – 10 August	3 days later
Washington, D.C.	56 km	4 May – 7 August	1 day earlier
Dover	95 km	11 May – 17 August	6 days later
Hagerstown	104 km	23 May – 2 August	18 days later
Harrisburg	111 km	25 May – 2 August	20 days later
Philadelphia	144 km	14 May – 2 August	9 days later

Where to buy watermelon plants and seeds near Baltimore

Buy plants ready to set out from 5 May to 13 August (from 14 April to 13 August for an unheated greenhouse); seed for raising your own is sown from 17 March to 16 July. Within 15 km of Baltimore OpenStreetMap lists 8 garden centres, 4 plant nurseries, 20 markets and 3 farm shops (collected 20 October 2026).

George's Farm Market — farm shop
Harford Road 7956, 21234 Parkville · Mon–Sun 08:00–17:00 · 11 km
Fruitland — farm shop
Eastern Boulevard 106, 21221 Essex · 11 km
Walmart Garden Center — garden centre
10 km
Maxalea Nursery — plant nursery
10 km · maxalea.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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