Recently there have been several boards threads on when a baby can be sleep trained. There doesn't seem to be a consensus among doctors, sleep experts, and parents. I've done so much reading on the topic, I can't believe I only recently remembered the book Bed Timing by husband and wife developmental therapists, Marc Lewis and Isabella Granic. Lewis and Granic suggest that it doesn't really matter how you sleep train, as all of the popular methods work. What matters most is when you do it. Children go through predictable developmental stages at certain ages (another great book to read on that is The Wonder Weeks), so timing sleep training around those stages ensures the least tears and most success.

The first good opportunity for sleep training is between 2½ and four months, they feel. “This is a period of relative stability and resilience,” the authors write. “There is no good reason not to try sleep training at this age if your intuition says ‘go.’ ” When babies are four to 5½ months is not a good time because “at four months, there’s a lot more smiling, giggling, and tickling games are starting to work,” said Lewis. “As your baby learns new interpersonal skills—skills that call for expected responses from you and lead to a stronger bond between you—it’s better not to disturb them until they’ve really begun to solidify.”


This really made a lot of sense to me! Many babies go through an infamous "4 month sleep regression," and Charlie was no exception. While his sleep was already bad before 4 months, it became exponentially worse after 4 months! Babies are going through an intense developmental stage at that time, becoming more social, and mastering skills like rolling over. We sleep trained Charlie at 4 1/2 months using the Ferber method when his quality of life had greatly declined due to exhaustion. Looking back now, I think we probably should have sleep trained him closer to 3 months. He was a big boy (90%), took to sleep training very well despite mastering rolling over in the middle of it, and we could have saved him weeks of exhaustion.

Personally, Granic and Lewis chose to Ferberize their sons at six months. The couple believe that at 5½ to 7½ months, "babies are engaged with the world of objects around them [more than they are with people] and show almost no sign of separation distress." It’s an ideal time to sleep train, they say. (source)

Because sleep training worked so well with Charlie, I always thought that we'd sleep train our second child. Olive is nowhere close to sleeping through the night (she wakes up 4 times during a 14 hour period), and her naps are usually 30 minutes or less, but she's happy, is getting enough sleep in a 24 hour period, and I'm just used to being sleep deprived as a second time parent. Olive is 5 1/2 months old now, and if we do decide to sleep train, it'll probably be within the next 2 months since 8-11 months is supposed to be when separation anxiety really kicks in, and sleep training becomes difficult.


Charlie left and Olive right. Wow Charlie was so much chubbier than Olive!

These are their recommended ages for good and not so good times to sleep train:

0 to 2.5 months - not so good
2.5 to 4 months - good
4 to 5.5 months - not so good
5.5 to 7.5 months - ideal
8 to11 months - really not so good
12 to 16 months - good
17 to 21 months - not so good
22 to 27 months - good
28 months to 3 years - not so good
3 to 3.5 years - good
3.5 to 4 years - not so good

For those of you trying to decide which sleep training book to read, this may be a good one to start with because they list the pros and cons of the 5 most popular sleep training methods, including Mindell, Ferber and Weissbluth. If method doesn't really matter, then you just have to find one that you feel comfortable with, and be consistent.

If you sleep trained, do you feel you should have done it sooner or later?