How Long Does It Take for a Giant Imperial Mix to Germinate?

Seed Preparation

• Giant Imperial Mix larkspur seeds require pretreatment to enhance their rate and speed of germination. Soak the seeds in room temperature water for roughly 12 hours, then drain them for 10 minutes on a sheet of paper towel. Healthy seeds will sink in water, so discard any seeds that float to the surface. Place the seeds inside a plastic sandwich bag filled with moistened sphagnum moss and place it inside the refrigerator for one month, remoistening the sphagnum moss often so it never fully dries out.

Indoor vs. Outdoor Germination

• In colder climates with harsh winters, Giant Imperial Mix larkspur seeds should be sown indoors six to eight weeks before the last spring frost so they have a head start before planting time. They can also be germinated directly outdoors, but only after all danger of frost has passed and the soil has warmed to 55 degrees Fahrenheit. In warmer climates with mild winters, Giant Imperial Mix larkspurs can be started indoors or outdoors, in spring or in autumn. Autumn sowing is especially beneficial in areas with very hot summers because larkspurs are cool-season annuals that will quickly fade once temperatures warm up.

Sowing and Germination Process

• Whether germinated in a pot or outdoors in a garden bed, Giant Imperial Mix larkspurs require lightweight and well-tilled soil. Sow the seeds at a depth of 1/16 inch, which is roughly four times the diameter of the seed. A constant temperature of 55 degrees Fahrenheit is required to successfully germinate larkspur seeds, and warmer temperatures may cause them to go dormant, so regulate the soil temperature in outdoor beds by spreading a light layer of mulch. Constant moisture is also required. Water the seeds with a light mist until the top 3 inches of soil feel very moist. Avoid watering with a heavy stream of water because it may dislodge the seeds. Healthy Giant Imperial Mix larkspur seeds will sprout in roughly one month.

Warnings

• Despite their harmless appearance, the seeds of Giant Imperial Mix larkspur are extremely toxic. They contain a high concentration of alkaloids that cause a variety of neurological and gastrointestinal symptoms if ingested, including dizziness, muscle spasms and abdominal pain. In extreme cases, the seeds can also cause death by asphyxiation. Wear gloves when handling the seeds and young plants, and wash your hands thoroughly afterward. Also, keep the seeds away from children and pets to prevent accidental poisoning.