Northern Light Auto

So your in a 9l pot. I'd guess about 1.5L should give 20% runoff. So what I would do is leave her until the pot feels really light to pick up. When it does give her a watering. 1.5l should be plenty to saturate the soil and give runoff. Empty the runoff from the drain tray and leave her again until the pot feels light. Keep watering in this way. Just to put it into perspective, with my 2 new plants... they are in 12L pots (3gal). I watered 2L before putting in the seed. Waited 24 hours. Then put in my seed. I didnt water again (NOT a drop) for 10 days. So depending on your temps and RH I would expect about a week before your need to water again.