I soaked my salvia seeds overnight in very dilute hydrogen peroxide (one ounce of 3% H2O2 in a quart of water).
They swelled right up like frogs' eggs and I got 60-80% germination from most batches even though some were a few years old.
In prior years I had very low germination (but might have covered the seeds with 1/16 - 1/8" of mix and then kept it too wet.
To keep the varieties separate, I soaked them in the cells of a plastic ice cube tray then scooped them out with tiny measuring spoons..
