When to plant cucumbers in Dundalk: 17 July – 5 September

In Dundalk, cucumber: sow for seedlings from 29 May to 8 August; plant into a greenhouse from 26 June to 5 September; plant out into open ground from 17 July to 5 September. For plants and seeds, the places nearby include Hardys (farm supply, 2 km); addresses and opening hours are below.

Cucumber in Dundalk: soil, season and weather

In Dundalk the soil, not frost, sets the date: the last frost is over around 20 March, but the top 7 cm of soil reaches 18 °C — the minimum on the cucumber card — only around 17 July, 119 days later.

Last spring frost	20 March
Top 7 cm of soil at 18 °C	17 July, 119 days after the last frost
Into an unheated greenhouse	26 June – 5 September; June outside: 10.6 °C at night, 17.6 °C by day; card 18–25 °C
First autumn frost	20 November, 126 days after the start
Days in the bed to the first harvest (card)	34
First harvest, if planted in this window	20 August – 9 October
Days left for picking	92
Daylight	17:09 on 19 June, 16:34 on 17 July
Watering outdoors when fruiting (card)	every 2 days; the driest month, July, has 15 rainy days

The same dates in Dundalk hold for Bell Pepper, Eggplant, Zucchini, Pumpkin and Watermelon.

Cucumber in Dundalk: care after planting

Planted on 17 July: in the first weeks water every 4 days.

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

24 July — feed: nitrogen

Pests and diseases of cucumber 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 Dundalk during the cucumber season

No month of the season averages above the cucumber card's 18–35 °C by day; the warmest, July, averages 19 °C. Months that stay below 18 °C even by day on average: September (16.5 °C), October (13.5 °C) and November (10 °C). Nights average below 18 °C in every month of the season, from 5 °C to 12.1 °C.

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
July	19	12.1	88	15	16:39
August	18.7	12	98	15	14:55
September	16.5	10.1	103	15	12:46
October	13.5	8.2	98	15	10:38
November	10	5	91	14	8:35

ERA5 2016–2025, Open-Meteo

Cucumber in nearby cities

All the nearest cities on our list plant cucumber earlier than Dundalk; the closest date is in Dublin, 1 day earlier.

City	Distance	Date	Difference
Dublin	73 km	16 July – 9 September	1 day earlier
Belfast	73 km	7 July – 4 September	10 days earlier
Athlone	120 km	13 July – 11 September	4 days earlier
Derry	126 km	13 July – 6 September	4 days earlier
Letterkenny	137 km	7 July – 13 September	10 days earlier
Sligo	138 km	30 June – 6 September	17 days earlier

Where to buy cucumber plants and seeds near Dundalk

Buy plants ready to set out from 17 July to 5 September (from 26 June to 5 September for an unheated greenhouse); seed for raising your own is sown from 29 May to 8 August. Within 15 km of Dundalk OpenStreetMap lists 2 garden centres, 2 farm-supply shops and 2 farm shops (collected 28 October 2026).

Killeavy Castle Farm Store — farm shop
14 km
Meigh Farm Shop — farm shop
14 km
Hardys — farm supply
Lisdoo, Newry Road, Dundalk · 2 km · joesphwallsonline.com
Dundalk Garden Centre — garden centre
2 km

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.

Questions