OK so let's recap.....
At the moment you are using plain water. Right? If you want to add to your water, use molasses. Unsulphured. 2 table spoons per gallon. But do not add anything else.
Take a pic or 2 of your whole setup. As is. Don't move the lights just take a pic so we can see what ya got goin on.
Do you have a fan to move air around? That will also help in making your plant stronger through the movement of the air and give fresh air. Growing in a closet, you need to have the airflow.
Run your lights 24-0. 18-6 may not be enough.
Having just transplanting them, they could be recovering from shock.
Going off of your posts, those babies are 25 days from sprout.
That pic at the top is about 5 days old. 3 weeks from sprout as of tomorrow.... Different light setup to you but I didnt start using any nutes until this past monday. Watered when needed. I will go take some pics in a bit to show you the diff. in just 5 days...
If ya got 20 bucks, Look up dudeoflife on here... He has his own nute lineup that I use and its awesome. 20 bucks will get you more than enough nutes.
Remember, try to keep temps around 75F. Humidity around 40% to 50%. I keep mine around 40%. Air flow is a must in a closet. No air movement will create alot of issues...