Getting a baby to sleep in a crib comes down to timing, consistency, and creating the right conditions. Most babies resist the crib because it feels unfamiliar compared to being held or sleeping in a smaller bassinet, but with a predictable routine and a few adjustments, the transition typically takes one to two weeks.
When to Make the Move
Most parents transition their baby from a bassinet to a crib around 4 to 6 months, though the timing depends more on physical milestones than age. Bassinets are certified for babies up to specific weight limits (usually 10, 15, or 20 pounds depending on the model), and you need to stop using one as soon as your baby starts rolling over or pushing up on hands and knees, regardless of weight. Rolling can happen as early as 2 months for some babies.
Room sharing for at least the first 6 months is recommended for safety, so if the crib is in a separate room, you can keep it in your bedroom during the early months or start with naps in the crib to build familiarity before moving nighttime sleep there.
Set Up the Crib Safely
A safe crib is a bare crib. Use a firm, flat mattress (never inclined) covered by a fitted sheet and nothing else. No blankets, pillows, bumper pads, or stuffed animals. This feels sparse, but soft bedding is one of the leading risk factors for infant sleep-related deaths. If you’re worried about warmth, a wearable sleep sack is the safest alternative to a blanket.
If you’ve been swaddling your baby, stop as soon as they show any signs of trying to roll over. A baby who rolls while swaddled can’t use their arms to reposition, which creates a suffocation risk. Transition to a sleep sack with arms free instead.
Get the Room Right
Keep the room between 68 and 72°F (20 to 22°C) with humidity between 30 and 50 percent. A room that’s too warm is a greater concern than one that’s slightly cool. Dress your baby in one layer more than you’d wear comfortably, and check the back of their neck or chest rather than their hands or feet to gauge temperature (extremities run cool naturally).
Darkness matters. Blackout curtains help signal to your baby’s brain that it’s time to sleep. Newborns are born without a functioning internal clock, and their bodies don’t begin producing melatonin (the hormone that drives sleepiness at night) until roughly 6 to 8 weeks of age. One case study found that melatonin rhythms emerged around day 45, with nighttime sleep aligning to darkness by day 60. Before that point, your baby genuinely cannot tell day from night, so exposing them to bright light during the day and keeping things dark at night helps calibrate their system faster.
Build a Short Bedtime Routine
A consistent bedtime routine is one of the most effective tools you have, and it doesn’t need to be elaborate. Research on young children found that a simple three-step routine, a bath, a brief massage or lotion application, then quiet activities like cuddling or singing, completed within 30 minutes total, significantly improved sleep outcomes.
The specific activities matter less than the consistency. Do the same things in the same order every night so your baby starts to associate those cues with sleep. End the routine by placing your baby in the crib drowsy but still awake. This is the single most important habit to build: falling asleep in the crib rather than in your arms teaches your baby that the crib is where sleep happens.
What to Do When Your Baby Cries
Expect some protest, especially in the first few nights. If your baby cries after being placed in the crib, one well-studied approach is graduated response: wait 2 to 5 minutes before going in, offer brief reassurance without picking the baby up, then leave again. Extend the interval by a few minutes each time. This method, sometimes called controlled crying or the Ferber method, typically produces noticeable improvement within one week.
The research on this approach is reassuring. In a trial of 235 infants averaging 7 months old, sleep training cut severe sleep problems from 14% to 4% and reduced the number of babies waking two or more times per night from 60% to 31%. A larger trial of 328 families found that parents in the sleep training group reported fewer depression symptoms two years later (15% versus 26%). No adverse effects on children have been reported in follow-up studies extending to five years.
If graduated response feels too difficult, a gentler alternative is to sit in a chair next to the crib while your baby falls asleep, then move the chair a few inches farther from the crib each night until you’re eventually outside the room. This takes longer but works for families who want to stay present. Either way, the goal is the same: your baby learns to fall asleep independently in the crib.
Why the Startle Reflex Wakes Your Baby
If your young baby seems to jolt awake moments after being placed in the crib, the startle reflex (called the Moro reflex) is likely the culprit. This involuntary reflex causes babies to throw their arms outward suddenly, which wakes them. It’s present from birth and typically disappears by 6 months. Before it fades, a sleep sack with a snug fit around the torso can dampen the reflex enough to prevent wake-ups without the risks of traditional swaddling.
Handling Sleep Regressions
Even after your baby is sleeping well in the crib, expect temporary setbacks. Most babies experience at least one sleep regression in their first year, and these are driven by developmental changes rather than happening at fixed ages. The most common triggers include learning a new physical skill (rolling, pulling up to stand), teething pain, growth spurts that increase hunger, and separation anxiety, which tends to peak around 9 months.
The 4-month mark is when many parents notice the first major disruption. This coincides with a permanent change in sleep architecture: your baby’s sleep cycles are maturing to resemble adult patterns, meaning they cycle through lighter sleep stages more often and wake more easily between cycles. This isn’t a problem to fix so much as a transition to ride out. Stick with your bedtime routine, keep putting your baby down drowsy but awake, and sleep typically stabilizes within 2 to 4 weeks.
Common Mistakes That Backfire
Rocking or feeding your baby fully to sleep before placing them in the crib creates a dependency. When your baby wakes between sleep cycles (which all humans do, multiple times per night), they’ll need the same conditions to fall back asleep. If those conditions involve being in your arms, you’ll be called back every cycle. Putting your baby down drowsy but awake avoids this pattern entirely.
Keeping the room too quiet can also cause problems. Babies who fall asleep in total silence startle awake at any household noise. A white noise machine at a moderate volume provides consistent background sound that masks disruptions and mimics the constant noise of the womb.
Finally, inconsistency is the biggest obstacle. Picking your baby up some nights but not others, or switching between the crib and your bed based on how tired you are, sends mixed signals. Choose your approach and commit to it for at least a full week before judging whether it’s working.