perlights a good ideal, never use it my self, I use less soil and let the soil dry out before watering, even when the top soil is bone dry the soil could have enought water for a 2-3 days more, when you have a good large root mass, you will need to water every 2 days if your temps and humidty are in a good range (20-30c) (humidty 40-60) and then the plants ready to be potted up