How to Grow Snapdragons from Seed (Antirrhinum majus)

Snapdragons are the cottage-garden flower everyone remembers from childhood — squeeze the side of a floret and the ‘dragon’ opens its mouth. They are also one of the most useful flowers you can raise from seed: dwarf types for pots and edging, tall spikes for the border and the vase, and a flowering season that runs from early summer until the first hard frost. The catch is that the seed is dust-fine and the plants need a long run-up, so the sowing date matters more than with most annuals. This guide covers Antirrhinum majus from a late-winter sowing to pinching, planting out, cutting and avoiding rust, plus how to choose between dwarf, intermediate and tall types.

• Sow February–March under cover; April direct for a late show
• Germination 1–3 weeks at 18–21 °C · surface-sow, seed needs light
• Plant out Late April–May, 20–30 cm apart, full sun, free-draining soil
• Flowers June until the frosts, if you deadhead or keep cutting

What kind of snapdragon to grow

Snapdragons are short-lived perennials from the Mediterranean, but in gardens they are grown as half-hardy annuals: sown under cover in late winter, planted out in spring and flowering the same summer. All the garden forms belong to one species, Antirrhinum majus, and the main choice you make is height, because that decides where the plants go and whether you need to stake them.

• Dwarf (around 20–25 cm). Types such as Tom Thumb form bushy little mounds smothered in short spikes. Ideal for the front of a border, window boxes and pots.
• Intermediate or half-tall (around 40–50 cm). The all-rounders: tall enough to cut a short bunch, compact enough not to need support in most gardens.
• Tall (75–90 cm or more). Long, straight spikes for the back of the border and for cutting. Give them a stake or a layer of netting.

Tetraploid strains carry a double set of chromosomes, which gives noticeably bigger florets and sturdier stems. You will find dwarf, semi-tall, tall, tetraploid and named colours such as Cherry Twist and Mango Twist in our snapdragon seed collection, also listed by botanical name under Antirrhinum majus.

When to sow snapdragon seeds

Snapdragons take around four months from seed to first flower, so the main sowing window is February to March under cover — a heated greenhouse, a propagator or a bright windowsill. Sowings in late January work too, especially if you grow the seedlings on under a lamp: our guide to grow lights for seedlings explains why early, light-hungry seedlings stretch without one, and the 10-hour daylight rule explains why anything sown much earlier simply sits still.

A sowing in April, under cover or direct into warm soil, still flowers, just later — from about August. The seedlings are tougher than most half-hardy annuals and tolerate a light frost once hardened off, which is why snapdragons also turn up in our February list for winter sowing in milk jugs. All our snapdragons are listed in the March sowing collection.

How to sow snapdragons: on the surface, in the light

• Use fine, moist compost. Fill a tray or small pots with sieved seed compost, firm it lightly and water it from below before you sow.
• Sow thinly on the surface. The seed is as fine as dust. Tip it onto a folded piece of paper and tap it off gently, or mix it with a pinch of dry sand for an even spread.
• Do not cover. Snapdragon seed needs light to germinate. Press it into the surface and, at most, dust it with vermiculite, which lets light through.
• Keep it warm and humid. 18–21 °C is ideal. Cover the tray with a clear lid or a plastic bag and keep it out of direct midday sun.
• Water from below. A watering can washes tiny seed into clumps. Stand the tray in water for a few minutes whenever the surface starts to dry.

Seedlings appear in one to three weeks. Remove the lid as soon as they do and give them the brightest spot you have; if they turn pale and floppy, see leggy seedlings: causes and fixes. Crowded trays of fine seedlings are also prone to damping off, so ventilate daily.

Pricking out, pinching and planting

Prick the seedlings out in small clumps or singly into modules once they can be handled by a leaf, usually three to four weeks after sowing. Grow them on somewhat cooler, around 10–15 °C, which keeps them short and sturdy. When a plant has three or four pairs of true leaves, pinch out the growing tip just above a pair of leaves. It feels harsh, but each pinched plant branches into five or more flowering stems instead of one.

Harden the plants off over a week or two and plant out from late April into May, after the worst frosts, in full sun and free-draining soil. Space dwarf types around 20 cm apart and tall types 25–30 cm. Snapdragons dislike heavy, wet ground, so add grit to clay or grow them in raised beds or pots. For tall varieties, push in canes now or stretch netting over the bed at about 30 cm, so the stems grow up through it.

How to grow snapdragons from seed: step by step

1. February–March: surface-sow under cover Fine moist compost, seed pressed in but not covered, 18–21 °C and a clear lid.
2. After 1–3 weeks: lid off, maximum light Brightest windowsill or a grow light; water from below.
3. 3–4 weeks: prick out into modules Handle by a leaf, never the stem, and grow on cooler at 10–15 °C.
4. 3–4 leaf pairs: pinch the tip Cut just above a leaf pair for bushy plants with many stems.
5. Late April–May: harden off and plant Full sun, free-draining soil, 20–30 cm apart; support tall types.
6. June onwards: cut or deadhead weekly Removing spent spikes keeps side shoots flowering until the frost.

Snapdragons for cutting or for the border?

The same species does two quite different jobs, and the way you grow it changes a little with each:

In the vase, snapdragons last about a week. Cut in the cool of the morning, strip the lower leaves and stand the stems upright straight away: laid flat, the tips bend upwards towards the light and you lose the straight spike. They sit perfectly between zinnias and cosmos in a mixed bunch — our guide to starting a cut flower garden from seed shows how to plan a bed around them. For tall spikes in blue, pair them with delphiniums and larkspur. If you are mapping out next year's plot this winter, a row of tall snapdragons at the end of a vegetable bed also draws in bumblebees — the only insects strong enough to prise the flowers open. See how to plan a vegetable garden.

Common mistakes when growing snapdragons

• Covering the seed. Buried seed stays dormant. Sow on the surface — more on light-sensitive seed in how to germinate seeds.
• Sowing too late. A May sowing indoors will not flower until late summer. Aim for February–March.
• Skipping the pinch. Unpinched plants give one tall spike and a few weak side shoots. Pinch once at three to four leaf pairs.
• Overhead watering and crowding. Snapdragon rust shows as brown-orange pustules under the leaves and thrives on wet foliage. Water at the base, space plants properly and do not grow them in the same spot every year; see common plant diseases.
• Letting them set seed. Plants that are left to form seed pods slow down. Cut or deadhead weekly to keep side spikes coming.

Frequently asked questions

Do snapdragon seeds need light to germinate?
Yes. Press the seed onto the surface of moist compost and leave it uncovered, or dust it with vermiculite at most. Covering it with compost is the most common reason snapdragons fail to come up.

When should I start snapdragon seeds indoors?
February to March for flowers from June. Late January works with good light or a grow light; sowings from April onwards flower from about August.

Should you pinch snapdragons?
For bushy plants with lots of flowering stems, yes — pinch out the tip once at three to four pairs of leaves. For a single extra-long spike for exhibition or cutting, leave the plant unpinched.

Do snapdragons come back every year?
They are short-lived perennials, and in a sheltered garden with free-draining soil plants often survive a mild winter and flower early the next year. They are usually weaker in their second season, so most gardeners sow fresh each spring. They also self-seed readily into gravel and paving cracks.

A pinch of snapdragon seed sown in February gives you more plants than you can fit in the border, and months of flowers for the vase. Combine them with cosmos, zinnias and the rest of our cut flower seeds, or browse all annual flower seeds. New to sowing? Start with our beginner's guide to growing flowers from seed, browse all our seed collections, or explore the rest of our growing guides.