Steps to Starting Gladiolus Early Indoors
You can start your gladiolus corms indoors about four weeks before your last frost date. Gladiolus can be started in either soil or water. Which method you use for starting your gladiolus early is up to you.
Starting Gladiolus Early in Water
Depending on how many gladiolus you have to start, choose either a shallow bowl or some other flat container that will hold a small amount of water and all of the gladiolus corms spread out. Fill the container with water to the depth of 1/4 inch (6 mm.). The water should just be deep enough to cover the base of the gladiolus corms. Place the gladiolus corms into the water, with the pointed end up and the scarred side down. Place the gladiolus corms and the container in bright, indirect light.
Starting Gladiolus Early in Soil
Gladiolus can also be started early in soil. Fill a container with 4 to 5 inches (10-13 cm.) of potting soil. Press the gladiolus corm into the soil pointy side up so that only half of the corm is in the soil. Water the soil and gladiolus corms so that the soil is damp, but not soaked. Keep the soil damp while the gladiolus are indoors. Place the container of gladiolus corms in a location with bright, indirect light.
Planting Sprouted Gladiolus Corms Outside
After your last frost date you can plant your sprouted gladiolus outside. Choose a location for the gladiolus that is well drained and has plenty of light. If the sprouted leaves on the gladiolus are under 5 inches (13 cm.) tall, bury the corm deep enough to also cover the sprouted leaf. Be careful not to break the sprout while you are covering it. If the sprout breaks, the gladiolus will not grow. If the sprout on the gladiolus corm is longer than 5 inches (13 cm.), bury the gladiolus corm 5 inches (13 cm.) deep and allow the rest of the gladiolus sprout to poke up above the ground. Starting your gladiolus corms indoors a little early is a great way to get a jump start on the season. By starting gladiolus indoors, you can be enjoying lovely gladiolus flowers when your neighbors still only have leaves.
