Plastic-free and fully FSC-certified, with a hemp gig bag, the Martin OM Biosphere must be one of the greenest guitars ever – but is it any good?

Martin’s second über-environmental guitar: the OM Biosphere reviewed

The Martin OM Biosphere
(Image: © Martin)

GuitarPlayer Verdict

Beautiful tone matches its organic design, sounding very natural, open and resonant, with strong sustain


  • +

    Environmentally conscious, aquatically artistic with resonant, organic tone


  • -

    Not quite as easily playable or sonically sophisticated as other options at this price

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Sometimes an acoustic guitar is more than an instrument. It makes a statement about who you are, and indicates your values and what you appreciate as an artist. The Martin OM Biosphere is such an instrument. It’s totally free of plastic and fully FSC-certified. Even its groovy gig bag is made of hemp. Forestry Stewardship Council certification means a product is made from responsibly sourced woods and ensures benefits of an environmental, social and economic nature for the forest and its local people. 

Showing support for the conservation of precious and increasingly endangered coral reefs, the OM Biosphere features an aquatic-themed top with an oceanic image by Robert Goetzl. The affable artist painted the cosmic scene for 2021’s 00L Earth Guitar as well, and the OM Biosphere is essentially a version-two of that admirable eco-conscious concept, this time in the form of an orchestra model.

Martin OM Biosphere

The Martin OM Biosphere features a beautiful aquatic-themed painting by artist Robert Goetzl (Image credit: Martin)

The top and certified woods make it rather fancy and slightly higher priced than its siblings

Goetzl painted a watercolor of a fascinating coral reef scene featuring a large green sea turtle soaring above an array of fishes colored mostly yellow and orange in contrast to the water, with its gradient of deeper to lighter blue sweeping from left to right. Silhouettes of a few divers survey the waterscape, complete with air bubbles emanating from their masks. The turtle is the star attraction, demanding your attention. As the turtle draws in your eye, it appears to be looking right back, an invitation, or perhaps a challenge, as if to say, “We’re watching you as well. Where do you stand?” 

Martin uses ink-jet printing to project the artwork onto the top, and protects it with a light satin finish. Subdued hues make it appear almost submerged, and wood grains show through, adding to the organic feel. I’m a total turtle dude and fell in love with the Biosphere’s top when the model was introduced at NAMM 2023. Fellow marine enthusiasts seem to feel the same way. Bring this guitar to the beach and everyone wants to know more about it, especially folks that already appreciate Martin guitars. 

The OM Biosphere has an interesting story because it’s a bit of a paradox, being simultaneously fancy and barebones. The Biosphere is built in the style of Martin’s workmanlike 16-17 series, American-crafted out of utilitarian woods and with minimal appointments, for maximum affordability.

Martin OM Biosphere

The OM Biosphere's headplate is made of ebony  (Image credit: Martin)

But the Bio is also a bit of a unicorn, because the custom top, which could practically pass for being hand-painted, and the certified woods make it rather fancy and slightly higher priced than its siblings in the 16-17 range, yet still less sophisticated and far more affordable than a Standard OM-28. The Biosphere’s top is tried-and-true solid Sitka spruce. The back and sides are solid sapele, which is a lot like mahogany. The binding is European flamed maple, the fretboard, bridge and headplate are ebony, and the neck is mahogany. 

The neck has the familiar feel of a classic Martin, with a modern standard 1 ¾–inch width at the nut and a taper designed for high performance moving up the fretboard. I enjoyed the feel in my hands, although the factory action was a tad on the high side for my taste. It’s adjustable with a truss rod that requires a hex wrench, not included, so I simply got used to it. 

Many guitars ship with such low factory action these days to make playing more effortless for a potential buyer. My approach is on the aggressive side, however, so if I had to choose, I’d prefer the action a tad high rather than low, where it’s susceptible to fret splat and delivers less resonance. 

Set up as such, and with a full 25.4-inch scale length, the Biosphere feels snappy and strong. It’s particularly well suited for fingerstyle and handled a hearty percussive approach from my acrylic nails, which were quite long at the time. The Biosphere also accommodated an aggressive approach from a thick pick. On the other hand, it sounded fine going to the other extreme and reacted with nuance to a delicate touch too. 

The Biosphere’s tone matches its organic design concept. There are no electronics, and its acoustic quality sounds very natural, open and resonant, with strong sustain. The tone is fundamentally forward, with a rather dry finish, and the sound is balanced across the spectrum, with an overall focus in the middle range. The factory strings are Martin Retro, made of a nickel/copper alloy designed for less attack response to allow more of the wood sound to shine through, and I felt like they did just that.

Martin OM Biosphere

The OM Biosphere has a mahogany neck (Image credit: Martin)

Compared to the deep sophisticated tone of the OM-28 Modern Deluxe, the Biosphere sounded somewhat shallow, but it’s understood that the price is twice as nice and the design goal is more stripped down. I dug the raw sound for blues and roots rock. It sounded right on point when I tried Drop D tuning and played Fleetwood Mac’s “Gold Dust Woman.” 

The Martin OM Biosphere is Martin’s second step in the über-environmental direction, and we’d love to see the company continue down that path with models of similar eco-conscious and artistic intent, in a variety of styles and prices. The top is endlessly interesting, and the body is comfortable. It’s mid-size, with a relatively shallow depth, making it a convenient grab-and-play guitar for the office and a fantastic travel instrument for the van, the campfire and on the beach. 

Jimmy Buffett passed during this review process. He was a Martin enthusiast as much as he was an ocean man, and I’ll bet he’s smiling down from his heavenly perspective on Martin’s new Earthly endeavor. For raising awareness about coral reef preservation in such an artistic way with musical merit, the OM Biosphere earns an Editors’ Pick Award.

Martin OM Biosphere

The Martin OM Biosphere's back and sides are made from solid sapele, which is a lot like mahogany (Image credit: Martin)


  • NUT WIDTH: 1 ¾”, bone 
  • NECK: Mahogany 
  • FRETBOARD: Ebony, 25.94” scale, 1955 style 18 sapele dot inlays and aluminum side dots 
  • FRETS: 20 
  • TUNERS: Grover nickel-plated, open gear with butterbean knobs 
  • BODY: Solid Sitka spruce top, solid sapele back and sides, scalloped Sitka spruce X bracing 
  • BRIDGE: Ebony with compensated bone saddle and bone bridge pins 
  • FACTORY STRINGS: Martin Retro Light Monel MM12 
  • WEIGHT: 3.6 lbs (as tested) 

Jimmy Leslie has been Frets editor since 2016. See many Guitar Player- and Frets-related videos on his YouTube channel, and learn about his acoustic/electric rock group at