While many gardeners propagate geraniums from cuttings, it is possible to do so from seed. Seed-grown geraniums offer heat tolerance and disease resistance, two things that ensure lower maintenance in the garden. They are a slow-growing plant, so they must be started early in order to be ready for bed planting in the spring. Begin the seeds approximately 15 weeks before you plan to set them outside; it will ensure that they'll be ready to bloom once in the ground.
Sterilize the seed pots before planting. Wash in a solution of one part bleach to 10 parts water then rinse well.
Fill the pots with a sterile soil-less seed starting mix to within 1/2 inch of the rim. Moisten the mix evenly throughout before planting.
Sow two seeds per pot directly on the soil surface. Cover with 1/8 inch of soil.
Cover the pot with plastic wrap then place it where it receives bright, indirect light. Maintain a temperature in the room of 70 to 75 F during germination.
Remove the plastic wrap and place the seedlings under grow lights once they germinate, approximately seven to 10 days after sowing. Set the lights 4 inches above the tops of the seedlings and leave them on for 12 to 16 hours a day.
Water once the soil surface begins to feel dry. Apply a half-strength liquid fertilizer every two weeks once the plants produce their second set of leaves.