March is the month everything changes in the Irish garden. After weeks of looking at seed packets and planning on paper, the soil is finally waking up and there is real work to be done.
What you sow in March determines most of what you will harvest from June onwards. I know that sounds dramatic, but it is true. Miss this window and you spend the rest of the season playing catch-up.
Whether you have a polytunnel, a raised bed or just a few pots on a south-facing patio, there is plenty you can get started right now.
What to sow indoors in March
Tomatoes are the priority. Sow them in a propagator or on your warmest windowsill. They need six to eight weeks before they can go outside, so a late March sowing lands you perfectly for a mid-May plant-out after the last frost.
At BloomySeeds we grow San Marzano for sauce and Cuore di Bue as a big beefsteak tomato for salads. Both are Italian classics that do very well in Irish summers, even the grey ones.
Courgettes are fast and satisfying. Sow one seed per pot, push it in on its side to stop it rotting, and keep it somewhere warm. They grow quickly and will be ready to plant out by late May.
Basil wants warmth above everything else. A late March sowing kept on a warm windowsill will give you strong plants by the time it is safe to move them outside in June. The Genovese basil from Franchi Sementi has noticeably larger and more fragrant leaves than anything you will find in a supermarket.
Brassicas including cabbage, broccoli and kale can all be started indoors now for planting out in April and May. Aubergine and peppers started in January or February need potting on now if they have outgrown their seed tray.
What to sow direct in March
From mid-March, once the soil has warmed a little, you can start sowing straight into the ground.
Broad beans are the hardiest thing you can grow and one of the most rewarding. They can go direct from early March in most parts of Ireland. Sow them about 5cm deep and 20cm apart.
Peas go in from mid-March. They tolerate a light frost without much complaint. Sow them 5cm deep in a double row and give them something to climb.
Spinach and Swiss chard can go direct from mid-March. They germinate quickly and you will be picking leaves within weeks.
Hardy flowers like cornflowers, calendula and nigella can all go direct from late March once the worst cold is behind you.
The varieties I recommend for March in Ireland
Not every tomato or courgette variety suits the Irish climate. Short summers and cool nights mean you need varieties that ripen reliably without needing weeks of Mediterranean sun.
For vegetables, I trust San Marzano tomato which is reliable even in a poor Irish summer, Zucchino Romano courgette for heavy cropping with excellent flavour, Basilico Genovese which is fragrant and productive on a warm windowsill, Cavolo Nero Tuscan kale which is extremely hardy and at its best through an Irish winter, and Pisello Telephone pea which is a tall classic with outstanding flavour.
For flowers, Fiordaliso cornflower mix is beautiful sown direct and loved by pollinators, Calendula arancio is easy and cheerful with edible petals, and Zinnia sown indoors now gives you colour all summer long.
All of these are available at bloomyseeds.com.
A note on germination
One of the most common frustrations I hear from Irish gardeners is seeds that simply do not come up. Cheap seeds, old seeds, or seeds that have been stored badly will let you down every time.
Every variety we sell at BloomySeeds comes from Franchi Sementi, Italy’s oldest seed house, founded in Bergamo in 1783. Their germination rates are tested before packaging. The Vintage 1928 range in particular has consistently strong results, even from seeds stored correctly over two seasons.
Quick reference for March
| What to sow | When | How |
|---|---|---|
| Tomatoes | All month | Indoors |
| Courgette | Mid-March | Indoors |
| Basil | Late March | Indoors |
| Broad beans | Early March | Direct |
| Peas | Mid-March | Direct |
| Spinach and chard | Mid-March | Direct |
| Cornflower | Late March | Direct |
| Cabbage and kale | All month | Indoors |
One last thought
March passes faster than you expect. The seeds that feel too early to sow today will feel late in three weeks. Get them started now and the harvest will look after itself.
