The Ultimate Guide to Growing Ammi Majus From Seed

May 12, 2026

How To Grow Ammi Majus From Seed

Ammi Majus is absolutely gorgeous in borders — it is tall so looks good at the back of the borders and it is also a brilliant cut flower. It is a superb annual that has cute, dainty white flowers and fine green foliage. I sow these plants from late February and they can be sown all the way up to May.

For anyone creating a cottage garden, cut flower patch or natural-style planting scheme, Ammi Majus is one of the best easy-to-grow annual flowers for adding softness and movement through summer. You can also browse our Individual Seed Packet for more flower seeds to grow alongside your Ammi Majus.

ammi majus - the rose press garden

Ammi Majus can be grown in autumn for a head start or in the spring for flowers in the summer. It is an annual so you will need to sow Ammi Majus every year, although it does self sow easily.

We grow Ammi Majus in well-drained soil in sun to partial shade, which means it isn't great for super shady gardens or borders.

If you love growing flowers from seed, you may also enjoy our Monthly Gardening Subscription Box which includes seasonal gardening jobs, seeds and growing inspiration throughout the year.

I sow my Ammi Majus in trays but you can sow them in pots if that is all you have to hand. Plus have a look at my blog for how to get pots for free from kitchen items.

Watch our video on how to grow Ammi Majus from seed, then go through the checklist below to ensure you are up to scratch!

Growing Ammi Majus

1) Fill trays with good quality compost

Ideally use peat-free compost where you can. The RHS guide to peat-free gardening is really useful if you're making the switch.

2) Sow the seeds over the tray

Try and keep them spread out so they are easier to separate and pot on later on.

3) Lightly cover the seeds with compost

I simply pick some up with my hands and lightly cover them (it doesn't need to be complicated!)

4) Water and place somewhere bright

Place on a sunny windowsill, in a cold frame or greenhouse. Once they have germinated, if you have them on a sunny windowsill you will need to ensure it is in a cooler part of the house e.g. porch, cold conservatory or a room with less heating. Ensure the seedlings have plenty of light.

You can find more seasonal sowing inspiration in our gardening advice blogs and our range of Ready To Plant Flowers & Plants.

5) Pot on into individual pots

Pot on when they have produced their first true leaves.

NB: We do not “pinch” Ammi Majus. It doesn't branch in the same way Dahlias or sweet peas do.

6) Harden off before planting out

I harden off Ammi Majus before planting out after the frosts have passed.

“Potting on” involves the process of moving young plants into larger pots to continue growing. The next stage in the process when they are ready is “hardening off”. This is the process of gradually acclimatising plants to outdoor conditions before planting them out in the garden.

The RHS guide to hardening off plants is also really helpful for beginners.

7) Alternatively sow direct

Sow direct in late spring or early summer and thin out to 20–30cm as they grow.

8) Support taller plants

Ensure you stake the Ammi Majus plants as they grow if you are in an exposed space.

Seeds sown in autumn and overwintered in a cold frame will produce bigger plants which will flower earlier in the year than those sown in spring.

When To Sow Ammi Majus

Sow: October–November or late February–May

When Does Ammi Majus Flower?

Flowering: June–September

If you enjoy growing easy annual flowers for cutting gardens and pollinator-friendly borders, have a browse through our full collection of Flower Seeds & Individual Seed Packets for more seasonal favourites.

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