imo,i do just lik ur doing,with little amont of water,only let it dry out and dont water twice a day.considr the plant size and cup size on amont of water.tak anotherpot sam size and soil mix as the one ur growin in,weigh its dry weight,wen plant ur growin weighs this amont or a little less water.i can get buy with watering a seedling as tall theoneur growin with 1 ounce of water.wen it starts usin that amont in one day,instead of 2-3 days ,up the amont by a 1/2 ounce or a little less.u can go by table spoon to at this stage,2 tablespoons=1 ounce.there are diff. ways of doing it too,with the watering.