Here are some things to consider:

- Water once every 3 days. Just enough to get runoff.
- Make sure you are not locking out nutrients, check your ph levels from the runoff water.
- make sure you have a good intake of air flowing, buildup of CO2 can cause this as well. The plants will suffocate.
- See through or opaque containers kill roots, make sure the roots are not getting ANY light and that you cannot see them.
- Make sure they are not "rootbound", now might be a good time to consider planting to bigger pots.

I am sure one of the things I mentioned is the problem. Troubleshooting should be relatively easy, with watering keep this in mind - Less is more. It needs a wet/dry cycle. Let it get dry, the plants prefer it this way. Stick your finger in the dirt about halfway near the stalk, if it feels moist, wait another day to water. On a side note, read my grow log for reference.