Seed
“For reasons that are not well understood, Salvia divinorum plants almost never set seed. Botanists have never found seeds on plants growing in their indigenous habitat, and I know of only four instances in which they have been found on cultivated plants. The seeds we are offering were obtained from a Salvia divinorum farmer in Hawaii who was willing to part with some of his precious crop.

The seeds germinate in approximately fourteen days, and the germination rate is typically about thirty percent. Almost all Salvia divinorum plants in circulation have been propagated from cuttings derived from only two clones, thus genetic diversity has been extremely limited. When you start new plants from seed you are establishing new, genetically unique individuals, and thus doing important work to help expand the genetic diversity of this rare species. Please be careful to label your seed-raised plants so that they do not get confused with other Salvia divinorum plants in your collection. Most Salvia divinorum plants are indistinguishable from each other, but occasionally a seed-raised plant will be visibly distinctive in some way.”

The only place where Salvia Divinorum seeds are sometimes offered is Daniel Sieberts Salvia Shop: www.sagewisdom.com The quote above is from his site.

Plant

Cultivation of Salvia Divinorum
Grow in as large a pot as practical (3-10 gallons is best for mature growth), filled with a loose, moist, very rich soil. The small shipping pots can be replaced immediately upon arrival with a 4" to 1 gallon pot. In all but the mildest climates (where temperatures never drop below freezing), winter indoors.
The plant will freeze to the roots with any frost but is root-hardy to about 25°. It likes warm, 75-95° summer temperatures, with the condition that the humidity is high. Mist in hot weather or keep in a high-humidity (above 50%) environment such as a greenhouse.
During the growing season (usually May to October), feed often (every two weeks) with a dilute high-nitrogen fertilizer. Inorganic farmers prefer mixtures such as MiracleGro (the acid variety is best). Organic farmers prefer high-humus, very well composted manure.
Do not fertilize during the semi-dormant winter months. Begin light fertilization in early spring and gradually increase until early fall. Distorted leaves and weak, leggy growth are evidence of over fertilization. Yellowing leaves will usually indicate too little food available for the plant to use. This can either be from too little food in the soil or from a soil that is too cold or from some type of root damage usually caused by the soil drying out.Yellow leaves can also be a sign of too little light or too low temperature.
Keep the soil moist but not soggy. Never allow it to dry out. If the soil ever becomes dry, the roots can become damaged and the plant will wilt or lose leaves. Make sure that the container and the potting soil that you use for the plant have good drainage. Never use ordinary garden soil or dirt or fresh compost when growing Salvia in pots. Always use a commercial potting soil. Doing so will avoid problems with drainage and parasites.
If you have problems with wilting or the edges of the leaves turning brown and dry, a simple humidity tent will often temporarily provide relief for the plants. (Quote from THEATRUM BOTANICUM )