A wicking bed is a thinner layer of lava rock with a thicker layer of potting soil or compost on top. There's a barrier between the rock and soil: perlite, weed blocker, etc. You keep water trickling into the bed and you have drain pipe buried horizontally just above the lava rock. The soil wicks water up and it stays perfectly moist all the time. You control the amount of moisture by adjusting the flow of water into the bed. No siphon or anything. It just constantly trickles in and out. Slick.

This will be better for starting from seed, for both transplanting outside in the spring and for some stuff that just does better in soil to just stay there.