5-8 days?seems like underwatering in my opinion..i also use 5 gallon buckets and use similar medium ,have holes for drainage and use rocks in bottom of buckets also and i have to water about every 3 days....4 if they r just babies.. i dont know if its true for every one but its been for me for 6 years..for indoors ...outdoors everyday sometimes except in fall...then i stop watering completely because we usually have enough rainfall until time for harvest