Select a container to start your seeds. Choose a seed-raising tray with drainage holes in the bottom. Fill the container with moist potting soil to within 3/4 inch of the top. Lightly press down on the soil with your fingers so it sits firmly in the container. Sow the seeds. Place the seeds on the soil with a 1-inch distance between them. Sprinkle soil over the seeds. Aim for a planting depth of 1/8 inch.
Moisten the top layer of soil with warm water. Use a spray bottle to moisten the soil — this will keep the seeds intact and won't rinse them away.
Cover the container with a clear plastic bag to help the soil retain moisture. Seal the bag with an elastic band. Keep the plastic approximately 1 inch above the soil surface. Stick a plant name tag in the soil to help hold the plastic up.
Place the container in a dark, warm area of the house. Phlox seeds need a temperature of 65 F to germinate. Use a space heater for additional heat, or place a heating pad under the seed-raising container.
Wait for the seeds to germinate. This can take anywhere from five to 10 days. Check the soil moisture regularly throughout the germinating period. Aim to keep the soil moist at all times.
Relocate the container to a bright area of the house. Remove the plastic from the container once the seeds start germinating. Place the container in a sunny window to expose the seedlings to at least 12 hours of light. Continue moistening the soil as needed.
Beautiful! These are really easy to split. I'd recommend doing it in autumn. You can lift the whole root out of the ground and divide and replant or you can go through the plant with a spade and break a piece off to plant elsewhere.