Cannabis likes to be watered thoroughly and then not watered again until the soil dries out completely. Dry soil promotes root growth and you want this. Learn to judge watering by feeling the weight of the pot; you'll know what "needs watering" feels like. You can even judge by looking at the plants -- when they get thirsty, they look sad and start to wilt. This is OK because the plants recover quickly once you water them, but the weight-of-the-pot method is recommended.
The need for watering will vary significantly during the growing process and will differ from plant to plant. This is why a fixed schedule like you have is not ideal.
When you water, water until water comes out of the drainage holes in the bottom of the pot. Water the soil from the middle all the way to the edges of the pot -- not just in the middle.