Good rule of thumb my friend if it looks dry water it and then wait for it to dry out again just like you would any other plant be that your garden daffodils or your Cannabis plants I am going to be transplanting my outdoors into the ground soon if you wanna be sure get down on your hands and knees and just unearth the top part of the plant if the ground beneath is very moist they she probably wont need any but if its dry even a few cms down she defenalty needs water :) Let your experience guide you my friend. your a seasoned grower I'm sure you will know when your plants need water and when they don't but if you think about it more closely it also depends on the temperature and climate of the country your growing in too alot can some into effect if you go into detail I'm sure you can find guides online that will advise you good watering routines for your part of the world :)