Plants of the genus Sempervivum go by many common names, including hen and chicks, stonecrop. Which is a direct translation of the Latin name. All species of sempervivum are small, low-growing succulent plants with a rosette form and spreading growth habit.
Although most sempervivums are commonly cultivated using vegetative propagation methods such as division, they also grow reliably from seeds if they are exposed to very warm, bright conditions and kept moderately moist.
Sempervivum seedlings are very susceptible to a fungal infection called damping-off, but this is easily avoided by not overwatering.
1. Fill a seedling tray with a well-draining growing mixture comprised of 2 parts coarse sand and 1 part perlite. Leave the top 1/4 inch of the seedling tray empty.
2. Sprinkle sempervivum seeds across the surface of the soil. Distribute the seeds so that only one or two lands on each square inch of the growing medium.
3. Spread a very scant layer of fine sand over the sempervivum seeds to help hold in moisture while still allowing light to reach them.
4. Mist the sempervivum seeds heavily after sowing them. Spritz the surface of the soil until the top 1/2 inch feels moderately moist. Maintain this level of moisture during the germination process.
5. Cover the seedling tray with plastic wrap to hold in heat and moisture. Apply bottom heat to the seedling tray using a propagation heat mat set to 90 degrees Fahrenheit.
6. Expose the sempervivum seeds to very bright light either by placing them near a large, south-facing window or by suspending a fluorescent lamp above them. Keep bright light on the seeds for six to eight hours every day.
7. Watch for germination in two to five weeks. Remove the plastic wrap as soon as the seedlings unfurl. Improve air circulation around the sempervivum seedlings by thinning them to one plant every two inches.
8. Decrease watering as soon as the seedlings emerge. Water with a spray bottle only when the top 1/4 inch of growing mixture dries out.
9. Transplant the sempervivum seedlings into 3.5-inch starter pots filled with succulent formula potting mix as soon as they reach 1/2 inch in height.
10. Keep the individually potted sempervivum seedlings in a warm, sheltered spot until they mature and take on their characteristic rosette shape, and then transplant them into permanent pots or directly into the garden.