GreenlyHelsinki: frost dates
Finland
In Helsinki the last spring frost usually comes around 6 May and the first autumn frost around 20 October, which leaves about 167 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 2 June.
| Last spring frost | around 6 May |
|---|---|
| First autumn frost | around 20 October |
| Frost-free days | 167 days |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.
When to sow and plant
| Crop | Sow for seedlings | Plant out in a greenhouse | Open ground |
|---|---|---|---|
| Achocha | 15 March | 24 April | 15 May |
| Arugula | — | 25 March | sow 15 April |
| Basil | 19 April | 27 May | 17 June |
| Beet | — | 25 March | sow 15 April |
| Bell Pepper | 14 March | 27 May | 17 June |
| Black-eyed Susan | 14 March | — | 15 May |
| Bok Choy | 20 March | 24 April | 15 May |
| Broad bean | — | 25 March | sow 15 April |
| Broccoli | — | 25 March | sow 15 April |
| Brussels Sprouts | 8 February | 25 March | 15 April |
| Cabbage | — | 25 March | sow 15 April |
| Calendula | — | 25 March | sow 15 April |
| Carrot | — | — | sow 15 April |
| Cauliflower | 11 February | 25 March | 15 April |
| Celeriac | 6 February | 24 April | 15 May |
| Celery | 6 February | 24 April | 15 May |
| Celosia | 6 April | 21 May | 11 June |
| Chamomile | — | 25 March | sow 15 April |
| Chayote | 30 January | 28 April | 19 May |
| Chickpea | — | — | sow 15 April |
| Chili Pepper | 22 March | 4 June | 25 June |
| China aster | 5 April | 27 May | 17 June |
| Chives | — | — | sow 15 April |
| Cilantro | — | 25 March | sow 15 April |
| Corn | — | 28 April | sow 19 May |
| Cosmos | 6 April | 21 May | 11 June |
| Cucumber | 15 April | 27 May | 17 June |
| Daikon | — | 25 March | sow 15 April |
| Delphinium | 15 February | — | 15 April |
| Dill | — | 25 March | sow 15 April |
| Eggplant | 18 March | 27 May | 17 June |
| Florence fennel | 10 March | 24 April | 15 May |
| Garden sorrel | — | 25 March | sow 15 April |
| Green Beans | 22 March | 28 April | 19 May |
| Hyssop | — | — | sow 15 April |
| Kale | — | 25 March | sow 15 April |
| Kiwano | 10 April | 12 May | 2 June |
| Kohlrabi | — | 25 March | sow 15 April |
| Leek | 14 January | 25 March | 15 April |
| Lemon balm | — | 25 March | sow 15 April |
| Lettuce | — | 25 March | sow 15 April |
| Lisianthus | 28 December | 25 March | 15 April |
| Lovage | — | — | sow 15 April |
| Luffa | 15 April | 27 May | 17 June |
| Marigold | 13 March | 24 April | 15 May |
| Melon | 5 April | 27 May | 17 June |
| Microgreens | — | 21 May | sow 11 June |
| Moringa | 10 April | 4 June | 25 June |
| Mustard greens | — | 25 March | sow 15 April |
| Napa cabbage | 22 March | 24 April | 15 May |
| Nasturtium | 17 March | 24 April | 15 May |
| Okra | 15 April | 27 May | 17 June |
| Oregano | 24 January | 25 March | 15 April |
| Pansy | 28 January | 25 March | 15 April |
| Parsley | — | 25 March | sow 15 April |
| Parsnip | — | — | sow 15 April |
| Peanut | 20 April | 27 May | 17 June |
| Peas | — | 25 March | sow 15 April |
| Petunia | 25 March | 27 May | 17 June |
| Physalis | 28 March | 12 May | 2 June |
| Pumpkin | 5 April | 12 May | 2 June |
| Purple coneflower | 12 February | — | 15 April |
| Radish | — | — | sow 15 April |
| Sage | 4 February | 25 March | 15 April |
| Snapdragon | 19 January | 25 March | 15 April |
| Spinach | — | 25 March | sow 15 April |
| Stevia | 24 March | 12 May | 2 June |
| Stock | — | 25 March | sow 15 April |
| Sunflower | — | 21 May | sow 11 June |
| Sweet Corn | — | 28 April | sow 19 May |
| Sweet pea | 11 February | 25 March | 15 April |
| Sweet William | — | — | sow 15 April |
| Swiss Chard | — | 25 March | sow 15 April |
| Thyme | — | 25 March | sow 15 April |
| Tomato | 16 March | 12 May | 2 June |
| Turnip | — | 25 March | sow 15 April |
| Watercress | — | 25 March | sow 15 April |
| Watermelon | 25 April | 27 May | 17 June |
| Zinnia | 30 April | 4 June | 25 June |
| Zucchini | 10 April | 12 May | 2 June |
Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day.
Helsinki: weather for the next 7 days
Forecast by Open-Meteo. Nights at or below 0 °C are marked as frost.
Planted in autumn
| Crop | Plant around |
|---|---|
| Bearded Iris | 20 September |
| Crocus | 20 September |
| Daffodil | 20 September |
| Garlic | 20 September |
| Hyacinth | 20 September |
| Lily | 20 September |
| Peony | 20 September |
| Saffron | 20 September |
| Tulip | 20 September |
| Wild garlic | 20 September |
A month before the first autumn frost, so the roots grow before winter.