Coco is not the same as soil. You need to use nutrients EVERY TIME!!!!!! When you water you need to think about watering the coco rather than the plant. The Coco stores the nutrients until the plant needs to use them. If you water with just water you wash out all of the beneficial bacteria, trichoderma etc and have to add it back in to get the performance out of your coco. Watering depends on the pots you use and the size. I use 5 gallon smart pots and I water every 3 days. This is a hydroponic way of growing so expect to go through water. Also the nutrients you use are important with coco, I wouldn't recommend skimping there. I use the canna coco line and I use the nutrients on the high end of their scale. I haven't been let down yet. You can also reuse your coco if you use cannazyme throughout your grow and add great white for the first few weeks of veg.