How to Sprout Penstemon From Seed

Soak the penstemon seeds in a bowl of cool water for 24 hours before sowing them. Do this in early spring approximately six weeks before the last hard freeze.

Sow the penstemon seeds in 3-1/2 inch starter pots filled with seedling compost. Place a seed on the compost’s surface. Sprinkle a scant layer of seedling compost on top of the seed without completely burying it.

Spritzing each starter pot with water from a spray bottle anchors the seed and moistens the compost at a depth of 1/4 inch. Spray each pot four or five times with the spray bottle. Maintain moisture at 1/4-inch depth during the germination process.

Place the starter pots outdoors in a cold, shaded spot for one to two weeks chilling the seeds. Make sure temperatures stay below 55 degrees Fahrenheit during the chilling period.

Move the starter pots into a cold frame or indoors onto a sunny, warm windowsill following the chilling period. Exposing the pots to very bright light for at least eight hours each day prompts germination.

Watch for sprouting in two to four weeks. Move the starter pots outdoors to a sunny, sheltered spot where temperatures stay above 60 F.

Transplant the penstemon seedlings into a bed with fertile soil and full sun as soon as nighttime temperatures stay reliably above 50 F.