Athosanswered grow question 6 years ago In soil you should fertilize no more than once per week, beware of dark green leaves, they are a symptom of too much grow nutrients.
As for watering, it not only depends on the size of the pot, but the size of the plant; the water you give the pot should be enough for the plant to use it in 4 to 7 days at most, anymore than that and the soil will stay damp too long: i) the wet soil will attract bugs, ii) the roots will have trouble getting oxygen, literally drowning the plant making it grow real slow.
A pot of soil usually holds around 20% of it's volume in water, so 57 liters of soil would need around 11 to 12 liters of water to be fully saturated (maybe a bit more), but if your plant is too small to use all this water, it could be disastrous).
Also, I would stop feeding and let the plant get whatever it needs from the soil; resume feeding once you notice the first symptoms of deficiency, 57 liters of soil should lasts the plant quite a while (11 liters of soil lasts me 7 or 8 weeks before needing liquid fertilizer).
How to tell when to water? When the plant needs water, you will notice the leaves will become droopy.
I would water with 2 liters, and check the plant daily for how long it takes to use that much: top soil feels dry? leaves droopy looking?