Gladioli: Sowing, planting and harvest calendar
How do you sow gladioli outdoors?
Check your material before starting: sowing gladiolus means using seeds, not corms. The organs sold as bulbs are planted, and should not be described as seeds sown ten centimetres deep. Gladiolus species can be raised from seed, but seedlings do not necessarily retain the characteristics of a named hybrid. To obtain exactly its flowers, use its corms and small cormlets instead.
For actual sowing, choose identified seed and follow the supplier's instructions for covering and temperature. In spring, a cool greenhouse or protected position makes specialist species easier to monitor than direct sowing into a border. Use a pot with drainage holes and free-draining seed compost, moistened before distributing the seed. Label with the name and date.
Keep the compost moist without waterlogging and protect seedlings from excessive cold, heavy rain and slugs. Whether they can stay outdoors depends on species hardiness and local temperatures. Not every gladiolus has the same growing cycle, so check the identity before deciding on winter conditions.
Prick out seedlings when large enough, taking care of their roots, and allow the small corms to grow. Flowering may take two to three years. Retain healthy foliage during growth, and do not confuse the absence of flowers in the first year with failed sowing.
When do gladioli flower and how do you care for them in bloom?
