How to Set Up a Child's Sleep Space

The cot setup is one of the rare parenting decisions where the safest choice is also the simplest and the cheapest. A firm flat mattress with a fitted sheet — and nothing else — beats almost everything sold to make a cot look "cosier", and most of those add-ons (pods, nests, bumpers) actually carry safety warnings from the Lullaby Trust. The same setup that keeps the baby safe also produces the best sleep, because babies fall asleep best in environments their developing biology can read.

Healthbooq has the full safer-sleep environment guidance — same numbers as the Lullaby Trust and NHS — for each age band.

The Sleep Surface

• Cot, Moses basket, or bedside crib that meets current UK safety standards (BS EN 716 for cots; BS EN 1130 for cradles/cribs)
• In the parents' bedroom for the first 6 months, day and night (NHS / Lullaby Trust — associated with around 50% reduction in SIDS risk)
• Travel cots that meet BS EN 716-1:2017 are fine for occasional use; mattresses are usually thinner but appropriate for travel

• Firm — should not indent under the baby's weight
• Flat — no incline (inclined sleepers were banned in the US in 2022 and are not recommended by the Lullaby Trust)
• Use the mattress designed for the cot, or a properly-fitting replacement to BS EN 16890:2017
• Waterproof cover or use a waterproof sheet protector under the fitted sheet
• The Lullaby Trust advises against secondhand mattresses where avoidable; if used, only from a trusted source, in good condition, with no signs of wear or damage

Bedding — fitted sheet only. No pillows, no duvets, no quilts, no loose blankets, no pods, nests, positioners, bumpers (including "breathable" mesh bumpers — Lullaby Trust advises against all bumpers), no soft toys, no comforters in the cot under 6 months. A small comforter is generally considered safe from 6–12 months.

If using a blanket instead of a sleeping bag: thin, single layer, "feet to foot" position (baby's feet at the foot of the cot), tucked in firmly, no higher than the baby's shoulders.

Darkness

Light is the strongest input to the circadian clock. Even dim light suppresses melatonin (the hormone that initiates and maintains sleep). The effect is biggest from around 6–8 weeks, when the baby's own melatonin production starts coming online; before then darkness matters less, but the habit is worth establishing early.

What "dark enough" looks like:

• You shouldn't be able to read a book in the room
• A small dim warm-toned (red/amber) night-light is fine if needed for night feeds — avoid blue or white light, which is most suppressive to melatonin
• Blackout blinds or thermal blackout curtains are the simplest fix; cheap stick-on portable blackout panels work for travel

Darkness matters most for:

• Daytime naps (where ambient light is highest)
• The first 1–2 hours of bedtime in summer when sunset is late
• The early morning when sunrise can be as early as 04:30 in UK summer

Temperature

16–20°C is the Lullaby Trust / NHS / AAP recommended range for infant sleep. The reasons are independent and both real:

• Above 20°C is associated with increased SIDS risk (impaired arousal from deep sleep)
• A warm room blunts the small (~0.3–0.5°C) core body temperature drop the body uses to fall asleep — sleep onset takes longer and sleep is lighter

Use a digital thermometer at cot height. Wall thermostats read at adult head height where temperature can be 2–3°C warmer.

Check comfort by touching the baby's chest or the back of the neck (warm, not sweaty). Hands and feet run cool in babies even when the core is fine.

See the dedicated room temperature article for tog-by-temperature dressing guidance.

Sound

A quiet room is fine. A noisy room can be helped with consistent white or pink noise — typical setup:

• Continuous (not music or app cycles), played from a separate device (not a phone you'll need to take with you)
• Around 50–65 dB measured at the cot — about the level of a quiet shower
• Speaker placed at least 1–2 metres from the baby's head, never inside the cot
• The AAP has noted that white noise machines played at high volume close to the cot can exceed safe sound exposure limits — check with a sound-meter app once

White noise is most useful in flats, terraces, busy streets, or shared rooms where sudden noises trigger the startle reflex. It is not necessary in a quiet room.

Air Quality

Less talked about but worth checking:

• Smoke-free home (any smoking in the house is an independent SIDS risk factor)
• Avoid scented plug-ins and strong fragrances in the nursery
• Reasonable humidity — 40–60% is comfortable; very dry rooms (e.g. with intense central heating) can disturb sleep through nasal congestion
• Cot away from radiators, draughts, and external walls where possible

Consistency Across Sleeps

The same sleep space for every sleep — naps and nights — produces the strongest environmental cue. A baby who naps in a bouncer and sleeps at night in a cot is being asked to read two different environments. Where possible:

• Naps in the cot from around 8–12 weeks (in the parents' room until 6 months)
• The same darkness, temperature, and white noise (if used) for naps as for night
• The same sleeping bag

Buggy and car naps happen — that's life. They're fine occasionally, especially in the first few months. Aim for the cot as the default day-time sleep place from around 12 weeks.

What's Worth Buying — and What Isn't

• Cot, Moses basket, or bedside crib meeting current standards
• Properly fitting firm mattress
• 2–3 fitted sheets
• 1–2 sleeping bags in the right tog for the room
• Digital room thermometer (£5–£10)
• Blackout blinds or curtains
• White noise machine (around £20)

• Cot bumpers (any kind, including "breathable" mesh — Lullaby Trust advises against)
• Cot pods, nests, or positioners (linked to suffocation deaths)
• Inclined sleepers (banned US 2022, not recommended by Lullaby Trust)
• Sleep wedges
• Pillows for under-1s
• Heavy blankets, duvets, or weighted blankets (weighted blankets not recommended for under 12 months by the AAP)
• Smart cot mats / breathing monitors as a SIDS prevention tool — they are not proven to reduce SIDS risk and the Lullaby Trust does not recommend relying on them

When to See Someone

• Cot found in unsafe condition (collapsed, damaged) — replace immediately, don't repair
• Concerns about the room being impossible to keep in 16–20°C range — see the room temperature article; talk to health visitor if needed
• Concerns about a secondhand cot or mattress — Lullaby Trust helpline (0808 802 6869) gives general safer-sleep guidance

A good sleep space does two things at once — keeps the baby safe and helps them fall asleep. Six things to get right: a firm flat mattress in a cot or Moses basket, a clear sleep surface (fitted sheet only — no pods, nests, bumpers, pillows, blankets, or soft toys), blackout darkness to support melatonin from around 6–8 weeks, room temperature 16–20°C measured at cot height, optional white noise around 50–65 dB at the cot, and the same setup for every sleep — naps included — so the environment becomes a reliable cue. Up to 6 months the cot lives in the parents' room (NHS / Lullaby Trust).