Doesn't seems to work for me. I first put them under a flood light after sunset. Then I even built a grow box and put them under 20/4 over 2 weeks and no progress as far as growing any new leaves.

Those clones average 5 inches, but I just tried some DJ blueberry and it's potent. I also currently have a Master Kush ultra flowing at around 3 inches. So April or even May is not the right time for clones.