PlantSowGrow
How to grow Snapdragon (Tall Mixed)
Antirrhinum majus
Spikes of velvety "dragon-mouth" flowers in every colour. Long-flowering and wonderful for cutting.
At a glance: Sow late January to early March.
When to sow, plant and harvest
Timed for a typical UK garden (last frost mid-April). The app uses your own town's frost dates.
Growing Snapdragon (Tall Mixed): what it needs
- Light
- Full sun · 6+ hours a day
- Watering
- Water in dry spells; pots daily in summer
- Soil
- Any well-drained soil
- Spacing
- 30 cm
- Height
- 90 cm
- In pots
- Grows well in containers
- Feeding
- Liquid feed every two weeks once flowering starts
- Hardiness
- USDA zones 2–11
- Difficulty
- Easy
Step by step
- Late January – early March · 12 weeks before the last spring frost
Sow Seeds Indoors
Sow in trays or modules of seed compost on a warm windowsill or in a propagator. Sprinkle the fine seed on the surface; do not cover — it needs light.
- 10–21 days after “Sow Seeds Indoors” · Late January – mid February
Check Germination
Seedlings should appear in 10–21 days. Keep the soil moist. If sown outdoors, thin them to 30 cm apart once they have two true leaves.
- 14–21 days after “Check Germination” · Mid February – late February
Pot On Seedlings
When seedlings have two true leaves, move each into its own small pot or module, holding them by a leaf, not the stem.
- Mid April · 3 days before the last spring frost
Harden Off
Stand plants outside by day and bring them in at night for 7–10 days so they get used to outdoor conditions.
- Late April – late May · 7 days after the last spring frost
Plant Out
Plant out 30 cm apart once frosts are over. Water in well.
- 14–21 days after “Plant Out” · Early May – mid May
Pinch Out Tips (optional)
Pinch out the growing tip above the third or fourth pair of leaves for bushier plants with more flowers.
- 14 days after “Pinch Out Tips” · Mid May
Add Support
Push in canes or twiggy sticks and tie in stems before they flop.
- 79–109 days after “Check Germination” · Mid May – mid June
First Flowers — Deadhead Regularly
Snip off faded flowers every few days to keep new ones coming for months. Take a photo for your journal!
- Mid October – early November · around the first autumn frost
Clear or Collect Seed
When frost blackens the plants, pull them up for the compost heap. Leave a few seedheads first if you want to save seed.
