In very short order our lettuce has sprouted! It actually sprouted several days before we left for vacation on Dec 29th, less than 10 days after we planted.
We have four modules up and running right now. I was actually surprised at the speed at which the lettuce sprouted so now I am in a mad rush to build more modules so that the lettuce can receive its proper amount of illumination. I should be able to get another four modules built this week. Maybe more if I work it over the weekend.