Wow, i cant believe only one person told you they are overwatered. That is what is wrong with them. Even the worst soil will have enough nutes in it to last 20 days. Those leaves look like cabbage or something....WAAAY to much water. You can even tell by just looking at the soil. Plants can go ALOT longer with little water than you think. One way to tell, if you are sure, when to water is to wait until the soil starts pulling away from the sides of the container. Or wait until the top 1-2" are absolutly bone dry. Trust me bro, you will notice when they need water before its too late. You arent going to underwater them. Lay off the water for awhile. Then next time you water add just a little bit of nutrients and water until a little bit runs out the bottom. You do have holes in the bottom right? If you dont, you need them. Just water until a little trickles out the bottom then stop. Those things are soaking wet. Good luck!