I'm on my first grow, but so far it's been successful. I started off two ways -- and the better result by far was germinating the seed in the rockwool and putting it under the CFL desk lamp right away. I did keep the cube in a dark closet until the little seedling was popping up just in case I hadn't pinched the opening completely closed and therefore ensuring the seed would pop, grow a tap root and push out the little plant with its cotyledons. But once I could see that, I gave it some light.
Then under the light for 16-18 hours a day until new leaves were growing and the root poked out the bottom. With everything done properly (no nutes, just water), it took 2.5 days to sprout and another 5 days to have new leaves and a root poking through the bottom. Then it went into my hydro system.