the amount of water an indoor plant needs will vary a lot.... depending on what light source you are using,the size of the pots and the temp (to name just a few of the variables).... I have been vegging with LED's and fluro's in 10 litre pots and its winter so its cool,,, I water them every 8 days or so but my flowering plants under 600w HID light need it every 4 days or so....I suggest that you just water them when they need it and not worry to much...most plants like their roots to be in moist soil and if the soil feels dry a inch or so underneight the surface then its time for a drink... hope this helps :^)