Simba Earth Source Mattress review: Firm support straight from the farm

In the UK, Simba is one of the top mattress brands on the market, with a wide range of hybrid options available. The Simba Earth Source is part of the Earth mattress collection, which is the brand’s first foray into more traditional sprung mattresses. Having reviewed many of the brand’s hybrid mattresses, including one of our all-time favourite mattresses – the Simba Hybrid Pro – I had high hopes for this sprung model.

The Simba Earth collection is designed using environmentally friendly, responsibly sourced British materials. All its wool can be traced back to British farms, and the mattresses are manufactured and hand-finished in Hampshire. The Earth Source is the range’s entry-level mattress and, in our tests, it proved to be great at minimising motion transfer, and providing a firm, supportive base. That said, its firm feel lacks the soft cushioning you’d typically get in a hybrid model, which makes it less comfortable for side sleepers.

Simba Earth Source mattress review: What you need to know

One of the most important things to consider when buying a mattress is your desired support level. The Simba Earth Source mattress is advertised as medium firm but, in my experience, I found the mattress to be very firm. Perhaps this is because I am used to sleeping on a hybrid mattress with a softer foam top, while the Earth Source doesn’t provide very much cushioning. In place of foam, the Simba Earth Source uses layers of wool underneath the soft plant-derived viscose top cover.

These include two quilted layers of cushioning wool, followed by a flat layer of Hampshire wool and a supportive British wool layer. Simba claims these layers add comfort, enhance support and maintain breathability.

Underneath all this wool, you’ll find a layer of ‘Aerocoil’ springs. These titanium alloy springs have a distinctive conical shape that is designed to respond to your body weight to provide the right level of support and pressure relief. Between that and the main sprung base, there’s another layer of wool to help provide stability.

Finally, you have the main bulk of the mattress: the “CoreMax” sprung base, in which up to 1,000 high-carbon steel springs are distributed across seven support zones. This helps to improve body alignment, while a reinforced outer frame reinforces the edge support.

The eight-layered mattress is 28cm deep, which is on the thicker side of average but should still be suitable for a standard fitted sheet and mattress protector. However, my standard sheets fit pretty snugly, so if you struggle with tight-fitting sheets, you may want to invest in something a bit deeper.

The mattress doesn’t feature a non-slip base, which means it’s susceptible to shifting and sliding around on your bed frame during everyday use. However, this makes it easier to turn, using the handles on each edge. Simba recommends users turn the mattress every few weeks for the first three months of its life, and then every six months thereafter. If you don’t do this, you risk invalidating the mattress’ 10-year warranty.

As the Simba Earth Source is a bed-in-a-box mattress, you won’t be able to test it before you buy. Thankfully, you’ll be able to use Simba’s 200-night trial period to ensure you’re fully satisfied with your purchase. If you’re not happy, you can return it for free for a full refund (excluding any delivery charges initially paid for).

Simba Earth Source mattress review: Price and competition

The Simba Earth Source mattress is more expensive than our favourite hybrid mattress, the Simba Hybrid Pro. Prices for the Simba Earth Source start at £849 for a single, then £1,199 for a double and going all the way up to £1,499 for a super king.

If that’s a little steep for you, you can find more of our favourite sprung mattresses listed below.

Alternatives and where to buy them

• Simba Hybrid Pro (from £799)
• Eve Wunderflip Premium Hybrid (from £999)
• Otty Original Hybrid (from £529)

Simba Earth Source mattress review: Comfort and performance

Unlike most online bed-in-a-box mattresses, the Simba Earth Source mattress was delivered flat, perhaps to maintain the mattress’ structure during transportation. While this made the mattress more difficult for the delivery men to manoeuvre up and down stairs, it was nice to not have to unfurl the mattress myself. All the really hard work was done for me – the only task I had to do was remove the protective plastic cover from around the mattress.

Other mattresses I’ve tested – particularly those with lots of memory foam – have come with a slight artificial smell when first opened, which usually dissipates after a few days. This mattress, however, smelled less artificial and a lot more like sheep. This is, I hope, caused by the high amount of natural wool fibres included in the top layers of the mattress. Thankfully, once the mattress had been uncovered for two days, the smell dissipated completely.

The base of a bed can slightly impact the feel of a mattress: for instance, a sprung-slatted base can give your mattress a softer feel than a solid base such as a divan. I tested the Simba Earth Source mattress on a slatted bed base and found that it offered very firm support. Despite its four sheepy comfort layers and Simba’s medium-firm label, I found the mattress far too firm for my liking.

As a side sleeper, my previous mattress had been too soft and I was hoping this firmness could help with my spinal alignment while sleeping. Sadly the Simba Earth Source caused me to wake up with joint pain, since it lacked the cushioning side sleepers require. The mattress didn’t soften at all in the night, either. My partner, however, found the mattress easier to sleep on – perhaps due to the fact that he sleeps on his back and is a little heavier than I am. If you’re likely to end up in a goldilocks situation like this, I’d suggest opting for a hybrid mattress that balances the support of a sprung mattress with the comfort of memory foam.

Frustratingly, it’s difficult to discern what each of the wool layers achieves on its own. Cushioning aside, I found the temperature of the mattress to be quite warm. Since I tested the mattress in the winter, I welcomed the warm feeling, but it’s difficult to tell how comfortable this will be in the summer time. Thankfully, sprung mattresses are generally cooler than their hybrid or foamy counterparts and wool has superior temperature regulating properties – which is promising at the very least.

Another positive is that the edge support was phenomenally good, meaning I could make the most of the mattress space. I tested the mattress in double size and never found myself fighting against my partner for space in the middle of the bed. Similarly, I found that the Simba Earth Source minimised motion transfer brilliantly well. That means when I was tossing and turning, my partner could sleep soundly.

Simba Earth Source mattress review: Verdict

I personally didn’t get on with the Simba Earth Source mattress as it was far too firm for me and wasn’t able to provide anywhere near enough cushioning for side sleepers. That being said, my experience isn’t universal. I thought its motion transfer was highly impressive for a sprung mattress, and its edge support was ideal for couples. Because of this firmness, Earth Source is definitely catered towards people who are heavier and especially back sleepers.

Add on to this responsibly sourced, traceable British materials, high-quality construction and a seamless delivery experience, and this mattress feels overall like a high-quality option. Its eco-conscious credentials are a rarity in the mattress industry, and this goes a long way towards justifying its higher price. Just bear in mind that a hybrid mattress might be more suitable for people who need a compromise between firm support and soft comfort.