Silentnight Plant Based Box Top 1800 Super King Mattress
The Silentnight Plant Based Box Top 1800 is a medium feel pocket spring mattress with a plant based comfort layer made from bamboo, kapok, flax and aloe vera.
- Plant-based natural comfort layers
- Minimises partner disturbance
- 60-night trial & 5-year guarantee
£744
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Silentnight Plant Based Box Top 1800 Mattress
More available sizes
Mattress details
Mattress
Silentnight Plant Based Box Top 1800 Mattress
Size
Firmness
Medium
Construction
Foam
Pocket Spring
Memory Foam
Depth (cm)
31
Layers
4
Layer Details
Tencel™ Lyocell sleep surface
A silky, soft touch top layer woven to allow airflow and carry moisture away from you as you sleep. In practice, that means a cooler, drier feel through the night.
Platinum comfort layer
Silentnight says this layer is ten times more breathable than memory foam while offering the same pressure relief. You get that cocooning, contouring feel with less of the heat build-up memory foam is known for.
Plant Based Comfort Layer
A cushioning layer made from a combination of bamboo, kapok, flax and aloe vera, which Silentnight says is sustainably sourced. This is where the mattress gets its plant based name and much of its soft, breathable character.
Mirapocket® springs and mini springs
800 Mirapocket springs adjust to your movements through the night, combined with 1000 mini springs for extra comfort and breathability. Each spring works independently, which means better isolation of movement between you and a partner.
Layer details from silentnight.co.uk product page, September 2026.
Key benefits
- 90cm each for two sharing: Two people get 90cm each, which means a partner who fidgets or turns is simply further away from you all night.
- Distance plus spring isolation: The 800 Mirapocket springs move independently, and combined with the extra width, movement on one side rarely travels far enough to wake you.
- Space for the whole household: When children arrive at 3am or a large dog claims the foot of the bed, this width means nobody ends up clinging to the edge.
- 30cm wider than a UK king: The UK super king is 30cm wider than the UK king and the same length, a difference you feel every time someone else moves.
- A cooler surface at scale: The Tencel Lyocell surface is woven for airflow, useful when three bodies and a duvet are generating heat across one mattress.
This size suits you if...
You share the bed every night and want your own undisturbed territory, children or pets regularly join you and a UK king has started to feel crowded, or you have a large master bedroom where anything smaller would look undersized. Allow at least 3m x 2.9m of floor space, ideally more, so you can still walk around it comfortably.
Consider another size if...
Your bedroom falls short of the 3m x 2.9m we suggest, or a bed this wide would leave no space for anything else. We'd recommend the UK king instead: it is 30cm narrower, the same length, and needs at least 2.7m x 2.9m.
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FAQ's
What are the dimensions of the Silentnight Plant Based Box Top 1800 super king?
This size measures 180 x 200cm, or 6ft x 6ft 6in. The box top construction makes it 31cm deep, a fuller profile than most mattresses, so check that your super king fitted sheets have deep enough corners before it arrives.
Is the super king Silentnight Plant Based Box Top good for restless couples?
It is a strong match. With 90cm of width each, a fidgeting partner is physically further from you, and the 800 Mirapocket springs plus 1000 mini springs compress independently, so movement stays on their side. Distance and isolation together do more than either alone.
What room size do I need for this mattress in a UK super king?
We suggest a bedroom of at least 3m x 2.9m so you can walk around the bed and open drawers without shuffling sideways. If your room is smaller than that, the UK king needs at least 2.7m x 2.9m and gives up only 30cm of width.
Is the super king big enough for children climbing in at night?
Yes, and that is one of the main reasons people choose it. At 180cm wide, a child arriving in the small hours still leaves both adults a reasonable share, and the independent pocket springs mean their wriggling is less likely to wake everyone else.
Where can I compare prices for the Silentnight Plant Based Box Top 1800 super king?
The prices shown on this page are pulled from retailers stocking this exact size and updated as they change them, so the table here is the quickest way to see what the UK super king currently costs and who has it available.