There are two things that pop in my mind when leaves start drooping. A watering issues or not enough light. Since you said that you are watering properly then id lean more towards the light. What size and spectrum are you using? How big is that homemade box? When was the last time they were transplanted? What type of soil are they in? What's the ph of the ingoing water? If you fill out the trouble shooting form properly and paste it on here it would help out alot.

You should start seeing little white hairs within two weeks from switching to 12/12. Were the nodes alternating before they went to flower?