Silentnight Healthy Growth Astro Eco Comfort Pocket Kids Double Mattress
The Silentnight Healthy Growth Astro is a hybrid kids' mattress built around 600 Mirapocket® springs, which means your child gets support that adjusts to their body rather than a flat, one-note surface.
- Free from foam & chemical treatments
- Zoned springs that follow their shape
- 60-night trial & 5-year guarantee
£329
Get the lowest price we've found
Save with the previous model
Some retailers still sell the earlier version of this mattress for less than the current model's best price.
Silentnight Healthy Growth Astro Eco Comfort Pocket Kids Mattress
More available sizes
Mattress details
Mattress
Silentnight Healthy Growth Astro Eco Comfort Pocket Kids Mattress
Size
Firmness
Medium
Construction
Foam
Pocket Spring
Hybrid
Eco-Friendly
Depth (cm)
24
Layers
3
Layer Details
Sleep surface
A breathable quilted sleep surface, which means the top of the mattress lets air move through rather than trapping warmth. It's a simple layer doing a simple job.
Support system
600 Mirapocket® springs providing zoned support, which Silentnight says is scientifically proven to improve spinal alignment and posture. Each spring moves independently, so support follows your child's shape as they shift about.
Comfort layer
Breathable EcoComfort Fibres™ sit in the comfort layer for cooler sleep. This is where the mattress gets its softness without using any foam.
Layer details from silentnight.co.uk product page, September 2026.
Key benefits
- The biggest size in the range: The UK double is 45cm wider than the UK single, so an older child or teenager gets adult-scale space without changing mattress.
- Fits a normal UK bedroom: We suggest a room of at least 2.6m x 2.8m, which most second bedrooms and first flats can manage with a wardrobe still in place.
- Genuine room for two: At 67.5cm each for two people sharing, the UK double works for the occasional visiting couple in a guest room as well as one growing sleeper.
- Bedding is easy and cheap: Double sheets and a 200 x 200cm double duvet are stocked everywhere, so dressing this size costs less effort than any non-standard alternative.
- Room for the pets too: A solo sleeper who shares the bed with a dog or cat keeps a comfortable stretch of mattress even after a corner has been claimed.
This size suits you if...
You're buying for an older child or teenager who has outgrown a UK single and you'd rather not replace the mattress again in a few years, you want a foam-free bed that can double as guest space for visiting couples, or your child's room is a decent size and a wider bed won't crowd it.
Consider another size if...
Your child's room is under our suggested 2.6m x 2.8m minimum, or a younger child simply doesn't need the width. We'd recommend the UK single instead, which is 45cm narrower and the same length, needing a room of at least 2.1m x 2.8m.
Similar Mattresses in This Price Range
Did you know? On Mattress Unboxed we have over 1,000 different mattresses to suit all types of sleepers. View all mattresses.
FAQ's
Is the Silentnight Astro in a UK double big enough for a teenager?
Yes, comfortably. At 135 x 190cm it's the standard adult couples' size, so a teenager gets far more room than they need and can keep the mattress into adulthood. The medium feel and zoned pocket springs suit a growing sleeper, and the size means you won't be replacing the bed when they hit a growth spurt.
What size room fits the Silentnight Astro UK double?
We suggest at least 2.6m x 2.8m, with around 3m x 3m the comfortable norm. That allows walking space on both sides and, in most rooms, bedside tables too. If you're furnishing a second bedroom with a wardrobe and drawers as well, measure carefully before committing to the UK double.
Does the Silentnight Healthy Growth Astro come in a UK king?
No. The UK double is the largest size available, alongside the UK single and UK small double. That makes sense for a kids' mattress: the UK double already gives a child or teenager adult-scale space at 135 x 190cm, so a larger size would rarely be needed.
Should I buy the Astro in a UK double or a UK small double?
The UK double is 15cm wider than the UK small double and the same length. If the room allows, the UK double is the more flexible choice, since it doubles as a proper guest bed for two. The UK small double suits tighter rooms, needing at least 2.4m x 2.8m against 2.6m x 2.8m for the UK double.
Will the UK double Astro get up a narrow staircase?
Silentnight doesn't publish specific delivery dimensions for this size, and at 135cm wide a UK double is trickier on turning stairs in older terraces or tight new build landings than the UK single would be. Measure your stairwell and doorways before ordering, and check the delivery details with the retailers listed on this page.