Dublin in September: what to plant
Over the last 5 years, September in Dublin has run 11.6–17.1°C with about 107 mm of rain across the month. Here is what weather like that will carry to harvest.
Everything above is a five-year average. In the game it is this — the weather Dublin is actually having, today.
Grow one in Dublin's weather right now →❄️ No sub-zero nights in September in the last 5 years — frost is not the limiting factor here.
🗓️ This month sits inside the frost-free window. Average last spring frost around Feb 10, first autumn frost around Nov 30 — roughly 294 frost-free days. Sow tender crops after the last frost date and make sure they finish before the first.
☀️ About 8.0 h of sunshine a day this month. Within the month it cools by about 2.8°C from the first ten days to the last — the window for autumn sowings is opening.
Sow this month — when would you harvest?
Assuming you sow in mid-September, then adding up the warmth Dublin usually gets, one day at a time — which is why some of these run past the end of the month.
| Crop | Days | Harvest around |
|---|---|---|
| 🌿 Garlic chives | 217 | Apr 19 |
| 🧅 Leek | 231 | May 3 |
| 🥬 Napa cabbage | 202 | Apr 4 |
| 🥬 Cabbage | 215 | Apr 17 |
| 🫘 Broad bean | 158 | Feb 19 |
⏳ Too late this month: Marigold, Strawberry, Cauliflower, Carrot, Daikon radish, Peas, Beetroot would still be in the ground when the first frost arrives (around Nov 30). Sow them earlier in the year, or grow them under cover.
🌡️ Cucumber, Tomato, Chili Pepper, Pumpkin, Edamame, Yardlong bean, Bitter melon, Luffa, Winter melon, Aubergine, Okra never accumulate enough heat outdoors in Dublin — not in any month. Locally these need a greenhouse or a warm windowsill.
Best crops to sow now
They are all ideal for this month — the only real difference is how long each one takes, so pick whatever you want to eat.
- 🏵️ Marigold about 82 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🌿 Garlic chives about 91 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🧅 Leek about 111 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🍓 Strawberry about 73 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🥬 Napa cabbage about 84 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🥬 Cabbage about 102 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🥬 Cauliflower about 92 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🥕 Carrot about 92 days to harvest Recent mean 14.4°C — right in the sweet spot
- ⚪ Daikon radish about 70 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🫘 Broad bean about 84 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🫛 Peas about 68 days to harvest Recent mean 14.4°C — right in the sweet spot
- 🟣 Beetroot about 68 days to harvest Recent mean 14.4°C — right in the sweet spot
Leave these for another month
- 🌶️ Okra — Recent mean 14.4°C is too cold (ideal 20–33°C)
- 🍆 Aubergine — Recent mean 14.4°C is too cold (ideal 18–32°C)
- 🍈 Winter melon — Recent mean 14.4°C is too cold (ideal 18–32°C)
Other months in Dublin
📍 Somewhere else? Look up your own city →
Temperature and rainfall come from Open-Meteo's historical observations for Dublin, averaged day by day over the last 5 years. Whether a crop finishes in time is worked out from its own starting temperature and heat requirement — those numbers are listed on each crop page if you want to check them.