Yeah, you need to change the way you are watering them because the way you are doing it is not correct. What you want to do is allow the soil to become almost completely dry all the way through. Then, water it heavily making sure to fully saturate the soil. Given the size of the container you are using, I estimate that you should be waiting 4 to 5 days between watering. The problem with the way you are watering it is that the bottom portion of the container always has moist soil because it is not given the proper time to dry out. This causes the roots to stay bound up down in the bottom rather than spreading out evenly throughout the entire container. Because of this, adequate oxygen is unable to permeate the root zone, causing slow growth. This situation also increases your chances of developing root-rot.
By allowing the soil to completely dry out, the roots are forced to spread out in search of water, colonizing the soil as it moves along. The dry soil allows oxygen to penetrate all the way through to the roots, boosting growth rates. Then, a heavy watering fully saturating all the soil gives them a drink just when they are most thirsty. At this point, you should allow several days to let your soil dry out, about 4 days. Then drench it to the point where water starts to flow from the bottom drainage holes. Take your time when saturating the soil, doing it slowly will ensure that the water fully soaks into the soil and does not just run out the drainage holes before it can be absorbed.
Are my lights not strong enough? How do they look?
