How to Sucessfully Night Time Potty Train in 5 Steps. Step 1-He has to be ready. Is he staying dry throughout the day with ease? Is he waking up with a dry diaper the majority of the time? Then he's probably ready! The phsyical ability to hold urine for long periods of time plus the nerve signal from the bladder to the brain to wake up to pee is both part of age - 66% of kids under three years old have night time control, and almost 75% have it under the age of four years.