in my own opinion, 18/6 would be better..
your plant needs some resting time also..
& when lights are off they stretch their roots a bit..
which is a good thing.. but, it's really up to you..
what method did you use?
the paper towel or the cup filled water method?
& do you have it in a humidity dome?
or anything that contains high humidity?
the soil has to be saturated & warm..
oh, i don't like that method..
it kind of takes too long..
the method i use takes a max of 4 days..
half cup filled water for 24 hours (1 day)
planting & waiting for sprout max 3 days..
most of mine popped on the 2nd day..
90% of the time, they pop on the 2nd day..
while they are kept in the humidity dome..
i think you will be fine though..
since you're doing the paper towel method..
just wait it out & it will come out of the soil..
I have done both 24/0 and 18/6 and in my opinion 18/6 is better. It saves energy, it strengthens the roots from the essential dark time, and it grows stronger and bushier plants. 24/0 does work well but I just think that 18/6 has the edge.