How Sway Is Turning Seaweed Into Scalable Packaging with Julia Marsh

Welcome back to the Sustainable Design Lab podcast. I'm Bernie Vander Dussen, and I'm Chris Bradley. And on the show, we spend a lot of time exploring the next generation of materials shaping packaging, and more importantly, how those innovations actually make their way into the real-world systems. And at the lab, we're working with brands and suppliers every day to evaluate, test, and scale those solutions, which gives us a front-row seat to where material innovation is gaining traction. And we're bringing you along with us. So today we're joined by Julia Marsh, co-founder and CEO of Sway. Sway is developing seaweed-based materials designed to replace flexible plastic films while also rethinking the role of feedstocks in supply chains within packaging. And in this conversation, we'll explore what makes the material viable at scale, why seaweed is really emerging as the poster child, this kind of compelling platform. And you'll hear directly from Julia, who has a lot of passion about seaweed. Like we do, and how innovations like this show up in real packaging applications. So, Giulia, welcome to the show. Welcome to the show, Giulia. Hi guys, nice to see you. Nice to see you too. Excited to have you on. You've been mentioned, I think, more than anybody else as an innovator or the forefront of material science here in packaging, so we're excited to have you on. I think across the board, we're seeing a wave of new materials entering the packaging space right now, both within natural feedstocks like seaweed, but then across the board, we're seeing massive momentum, in my opinion, with what's new. From your perspective, what signals tell you that a material is actually ready to move on beyond innovation and into real adoption and scalability? I love that there's so much attention going into biomaterials right now. It makes me really hopeful for the future. And I know we'll get into the politics or the conversation around why they're not moving faster, but I think what really indicates to me after 5 years of learning, is a material ready to go into the world or not, is what are the folks on the fulfillment line saying? Does procurement really feel like they're on board with this product? Because you can have all the impact stats. And the gorgeous design, but if it doesn't really work and it's not easy to use, then it's not gonna scale. So that's what I'm really enjoying, you know, being at that stage with Sway now where we get the feedback from the most skeptical people in the supply chain saying, hey, this is pretty strong. I think this is gonna work. It's really exciting to hear that you're making progress with Sway, and there's a lot of different bio-based materials that are being explored, but they really do come with trade-offs. Tell us a little bit about what led you to seaweed and how you think about it compared to some of the traditional feedstocks like paper, cellulose, PLA, other biopolymers. I think every material has a role to play and there's no silver bullet. I think everyone agrees with that. So what I identified as a gap early on prior to building Sway was one, I think there's only so much that reuse and true recyclable materials can do. So there is a need for compostable materials. And then within compostable materials, there's gaps in performance or resource efficiency or end of life, or just the overall impact of the supply chain that could be optimized. And that's why I fell in love with seaweed. Seaweed is just super resource efficient. I think everyone listening to this podcast already knows, but I'll say it anyway, which is You know, we don't need fresh water. You don't need land. We don't need pesticides. The natural polymer inside of seaweed lends itself well to pliability and elongation and durability. So there's lots of performance features that come uniquely with seaweed. We've designed our materials for home and industrial compost. So you have options at end of life. And then finally, you have a much bigger impact of just a material that is actively improving ecosystems and communities. And that's really why I started the company. As we've grown, there's lots of reasons to work with seaweed and to work with Sway, but the piece I'm most excited about is as we scale, we should see a proportionate positive impact on ocean health and with coastal communities. And that's so cool. It's like packaging that does more than just protect what's inside, but actually protects what's outside. Wow, I love that. Packaging that's more than just what protects from the inside. Packaging that does more. I love it. You know, a lot of sustainability conversations that we have are focusing on reducing across the board, whether that's material, but mostly impact, you know, but Sway really leans into the regenerative side of systems across the board, not just the material, but the systems like you were mentioning. How does that show up in the way that you think about sourcing and production and long-term scale? Yeah, there's two pieces to that. So one is similar to other packaging strategies, reducing the amount of material used or advocating for reuse. You can still do that with compostable materials. Our materials require less overall to do the same job. In a lot of cases, you can use a thinner film to do the same job that a PLA film might do, which is a fun learning. Or if you wanna reuse our bag a bunch of times, You can, we've tested it. So I don't, I just wanna answer that piece first because I think compostables are often put in the bucket of they compost, but they can also be reused and they can also be a reduction. But when we think about sourcing and doing more and being additive, we're really cautious of who we're sourcing from, the kind of seaweed that's grown, how it's cultivated. We know what's happening in the water, how it's being processed, and we've designed a pretty rigorous sourcing scorecard. That all of our farmers and processors go through so that we know the direct positive impact of our supply chain. And then we're able to actually pass that data to our customers and then they get to claim that. The impact story comes with receipts. You wanna know how much carbon that seaweed sequestered? We can tell you. Or you wanna know how many pounds of excess pollutants were drawn out by the seaweed? We can tell you that too., and we can also tell you how many acres of biodiversity or habitat were protected through our sourcing. So it's pretty cool. It's like, I don't know, most people haven't visited a seaweed farm. It's a foreign concept for most. And I think that that kind of transparency and that amount of detail can be a nice way to invite people into envisioning what a seaweed farm is like. And I love that as a marketer, 'cause there's the whole story that comes with it that you can tell about your packaging. And, you know, and at The Lab, we spend a lot of time, I would say, translating different types of materials into different applications. And so where are you seeing the strongest fit for seaweed-based materials today, and where is it still evolving? There's so many seaweed material companies, which is so exciting. It's not some niche project happening in a lab somewhere. It's like a category now where there are innovators working with seaweed on, you know, every continent except for maybe Antarctica. And I love that we're a part of like a sea of solutions. So while Sway is focused on film, I love that seaweed's being used to replace, you know, utensils and create new paper and create coatings and so many things. At Sway, we're really passionate about flexible films being compostable because it's a category of plastic that just doesn't get recycled. And for our material specifically, which we call TPC Flex, thermoplastic seaweed, flexible film. We think it makes a lot of sense in places where packaging is a part of the story and it's necessary. So poly bags used in the fashion industry are a big focus. My big dream is that we just stop using poly bags. That would be best. So I hope that this particular application is a transitional technology, but there's 180 billion plastic poly bags used every year in the fashion industry alone. And our material's really good at doing that job. If you put a beautiful cashmere sweater in a Sway bag in Thailand and you ship it to the United States, it's gonna show up in perfect condition. So the poly bag as well as the retail bag, those are two really early focus areas for us. And I think anywhere where, again, there's no good recyclable or reusable solution, that's a good spot for our technology. I would love to see Sway come as an e-com. You're opening your box and you're looking for your very nice sweater and to see Sway there would be really, really cool, cool moment. When brands are evaluating new materials, performance is often a gating factor, like you mentioned, like to get from a very expensive, beautiful cashmere sweater to the consumer that has to perform. How have you approached balancing the functional requirements also with sustainability goals? Well, our requisite is that any component we use in our materials must be certified home compostable. We're not willing to negotiate around that fact, so You're guaranteed if you use a Sway product, it will compost in a backyard environment in less than 180 days according to the TUV standard. Outside of that, we're really open-minded about how to engineer these products in partnership with traditional plastic manufacturing to make sure that these materials perform and do their job. We wanna always load as much bio-based content in as possible, so that also kind of constricts the formulations we can work with. But we've unlocked a lot of processing efficiency in partnership with our manufacturers so that we can kind of fine-tune and tweak the performance attributes of our films to do different jobs. So some of them might be really grease resistant and others might be more moisture resistant, and it, it just depends on the, the performance quality that you want. And so long as we never depart from our mandate around home compostability, we're kind of, I guess, assured of the impact of the product, at least at the end of life. I love that. As far as having something that can wind up in a number of different environments and not just, you know, an industrial compostable standard or something, but something that really could survive or make it through a backyard compost. From your experience, what are the biggest barriers to scaling a new material? I know you've been at it for a while now, and which of those are really technical versus behavioral or market-driven? Yeah, such a good question. I feel like my answer would change year to year. Now that we've really figured out the technology and we're commercializing, the answer is just cost. It's just getting that cost down. And we have a really good plan to get the cost down now. The biggest blessing that happened last year in 2025 was the partnership that we developed with Charter Next Generation, who is our film manufacturer. And they're just amazing. They believe in the future and they want to make it happen. And together we've built a great plan to get the cost down. To where it's gonna be reasonable. We're already less expensive than the leading compostable polybag, and we have a plan to get down from there. So I'm feeling really good about that, but it's certainly the biggest challenge. And then the second piece, like you mentioned the behavioral earlier, it was finding the right partners who could see the writing on the wall and wanted to be a part of that story. Like, this is inevitable. Plastic will always have a role to play, but there are new materials coming in they help abate risk, they're interesting, they have unique properties, they're compelling, they perform well. Like, why wouldn't you wanna dance with the future? So I think really that was like the biggest effort leading up to this point is just creating a, a window or opening a door to working with Sway in the first place. And now that we're over that hump, it's really just, yeah, let's get the cost down. I wanna jump back a little bit 'cause you talked about in the beginning a little bit about supply chain and the importance of getting the people who are on the ground using materials, their feedback and their buy-in essentially. And the supply chain of seaweed is very different than traditional plastics. And so I'm curious from your experience of building Sway and getting it to where it is today, what have you learned about building and scaling that kind of ecosystem and the differences between that and the traditional poly supply chain? If we're being really honest, the reason that Sway exists Yes, is to address plastic pollution, but the primary motivator is to work in partnership with seaweed farms. So you have to be really thoughtful about how you build that series of relationships. And seaweed is dynamic. It grows in the ocean. It's a dynamic environment. The ocean is, you know, like not something that humans can control. So I think what might make it different is that you have to account that people are farming in the water and weather is a thing and nutrient density is a thing and processing timelines are a thing. Fortunately, seaweed farming for the most part is a really well figured out commercial industry, but we work with all different kinds of farmers and processors because we're always trying to diversify the types of seaweed that we're working with and who we're sourcing from. So I think as we scale, that'll become more and more a focus is How do you account for a dynamic sourcing story where you're operating in the ocean and you can't control the ocean? Packaging is entering a new era where sustainability is tied directly to cost compliance and design decisions. So we pulled together our 2026 Packaging Trends Report. It's not just trends, it's what we're actually seeing across the industry. Fiber expansion, natural polymers, refill systems, and a real shift towards more accountable, data-driven packaging. If you're trying to stay ahead of where things are going, it's a must-read. Download it for free at sustainabledesignlab.com or check the link in the show notes. You know, we often see a gap between the way that materials are designed and the systems fully function. So when we start to look at the end-of-life infrastructure for compostable materials and the realities are there, how do you think about that as you develop your materials? Yeah, it's a spicy topic. I believe in a future where composting is normal. I really believe it's inevitable, mainly from the lens of we need to deal with organic waste in a responsible way so that we're not contributing to 7% of global emissions every year. And compostable packaging is a part of that story. I've learned so much. It's a meaty topic. I think the best way for compostable materials to play a role in that story over time is to serve a function. So if we are a vessel for more organic waste going into compost, that's a value add for composters. If our material contains nutrient content from the seaweed itself, that's a value add. And then it's about people having like familiarity and, and access. So I think equal parts with building a responsible sourcing strategy is building relationships with composters. It goes beyond Does this thing actually disappear with no microplastics and toxins? And actually means let's test it in literally every environment, which is what we're doing. Let's test it in your home. Let's test it in that person's home. Let's test it in this like industrial pile. Let's test it on a winery in Sonoma and make sure it goes away there too. So really building relationships with composters to help build trust and say this thing really does go away. That's a big part of our focus as well. And then hopefully more, more composting in general happens. I want to jump back again a little bit. You said that flexibles are a big focus for Sway because of the recyclability challenges with traditional flexible plastics. What have you learned about the broader system by focusing on just flexibles? Because I know that you guys do flexibles, but there's so much more out there when it comes to packaging and compostable packaging. How has your focus on flexibles really helped your understanding of the greater packaging systems? A lot of brands are shifting towards pouches and bags and wrappers as the lightest weight option and probably the most affordable option to package their products. So it's been really interesting to foray into the flexibles landscape at a time when it's like the pouchification of everything. And we're operating in this compostables landscape at the same time as there's this huge shift towards fiber and trying to invest in more responsible fiber recycling. So I think what that's brought to mind is one, there's a lot that a compostable flexible film can do and solve for, maybe more so than ever before, because there's an openness to working with flexibles where there wasn't prior. And second, I'm thinking about how can we help improve the performance qualities of those fiber-based substrates or wherever they're being used. Is there a place where responsibly sourced paper can be improved by pairing it together with Sway. So just between us, but not really between us, we are of course interested in working together with paper companies to provide barrier properties with our films and coatings. And that gives you so much more opportunity, recyclability and compostability and this gorgeous seaweed story. So we're not the only ones doing that, of course, but it is, I think, yeah, been illuminating how can we improve what paper's already doing and also lessen the burden placed on paper to save the whole packaging industry. It's a tough challenge. I think EPR is one that, you know, gets brought up in every conversation that we're having. And part of the big momentum and the drivers of sustainable packaging that we're seeing in 2026, EPR is, if not the biggest, one of the biggest. And I think that that speaks to even what you're seeing is this pouchification, which I like that, of different substrates and actual applications and functional designs where flexible packaging is more than anything, even though they have recyclability challenges, we're seeing more and more because of EPR. So I agree with that. I think that that's an interesting take. And I know you've worked with a lot of really cool brands and what tends to really unlock the decision to move forward because they evaluate, they're doing pilots, but is it sustainability goals, regulatory pressures like EPR? Brand differentiation, the story? What have you found to be the biggest driver of adoption? All of the above. I mean, certainly seaweed is the invitation. You come for the seaweed, you stay for the performance. I think that people are like intrigued about being able to marry the thoughtfulness of their product design with a thoughtfully designed material. And that's the most common reason that people come to us. But the reason that they actually engage is it works. It does the job. And compared with maybe some of the other options they were considering, it requires very little changes in fulfillment. So your operators are not going to be annoyed with you. It's really easy. They're kind of interchangeable in terms of performance. And then you get all these benefits that come with it. And, you know, as policies like EPR evolve, are you seeing them accelerate innovation in materials or create new constraints that companies need to navigate, specifically in the US as different states incentivize different end-of-life outcomes? Yeah, it feels like the Wild West. It's like half and half. Some brands say it's a mess right now. I believe in this future. I care about not creating more piles of waste. I'm not going to keep using plastic. I believe that materials should be designed to return to the Earth. Fundamentally, wherever EPR lands, that's what I'm going to do. I'm going to move forward. Or I happen to be in a region where compostables are being rewarded, compostable, like flexible films. And then the other bucket, yeah, that is, that's a big reason that people hold off on activating with Sway is they say it's too confusing. I don't know where this is going to land and I'd rather just wait. So I would say it's, yeah, it's a mixed bag. It's hard to say if EPR has been more helpful or hurting, but overwhelmingly we're thrilled that there's more awareness around Yeah, EPR is here, it's coming, it's present, it's contagious, it's going to spread, and we're going to only get more clarity over time. And I know you've talked a lot about the whole ecosystem around seaweed, but if you do zoom out and you kind of look across that ecosystem— suppliers, converters, brands, the infrastructure— what does it look like when this really scales in a meaningful way? Maybe give us a little vision of, of how you see that all coming together. You want a vision of a thriving future or you want a map of how all those partners are working with our material? I think I'd rather hear the vision of the future. What is it going to look like when it's really functioning the way that you envision? I always say ubiquity in the best possible way, because in a true vision of the future, let's call it 10 to 15 years from now, there's been a dramatic reduction in material usage overall, just through clever design and probably process changes in the way that fulfillment works and the way that we're thinking about materials as designers and as visionaries. So let's call that 50% reduction. And then the rest goes to recyclable materials, reusable materials, compostables. And I hope that Sway is playing a significant role in really addressing the places where recycling or for reuse are not feasible. So that's like your snack wrapper. It's like the things that you would find in a bodega. You go to Target and there's like a wall of granola and it's packaged in soy, and you're ordering something online and it's this gorgeous beauty product and it comes, you know, protected in a soy packet. But those are the kinds of places that I hope— it's not very sexy, but if we achieve ubiquity, it means a direct correlation with acres of ocean protected, biodiversity protected. The more the seaweed is growing, healthier the ocean ecosystem is, the more jobs we create. There's literally like 100 million jobs that the seaweed industry can support. That thriving future means that those materials aren't just ending up clogging up our systems or turning into microplastics, but actually going back into nature and creating more compost. And that compost is feeding a healthy food system. So I think the manifestation of the material may not be So glamorous, but what it means is that the supply chain is succeeding and that means healthier oceans and it means healthier soil and it means healthier humans. If we have a lot of packaging engineers, designers, or sustainability folks who listen to this podcast, and you mentioned a few times that how easy Sway is, is almost a drop-in replacement. Of our listeners who are evaluating new materials today and evaluating, looking for another alternative, what should they be prioritizing when deciding what's worth piloting or trying out? Is the question, is it worth it to pilot with Sway? Because the answer is always yes. I think the question is when they're evaluating new materials, what should they be prioritizing to identify what works best for them and their product? Yeah, I think it's prioritize, does the material inherently work already within my system and does it do the job already? And not trying to force materials into systems where it doesn't make sense. If you're looking for something that is waterproof and can last forever, you probably aren't working with compostable material. You're probably working with aluminum or glass or something else. I think of it through the lens of like, what does the material inherently want to do? Which I think every packaging designer already knows, but when you're working with biomaterials, we receive so many inquiries to force the material to do something that it's just not designed for. And then I think. If the question is, this might work and maybe I'll get my team on board if we just had 25 samples, which honestly is the deciding factor for so many of our customers, is literally just having it in hand and being like, oh, I thought this would be weak, or I thought it would be brittle, or I thought it wouldn't work. And just testing a small amount, it is kind of game-changing. So, you know, seeing is believing is the general feedback. You mentioned a little bit about your vision for the future, but when you think about the future, of packaging specifically, what is one thing that gives you hope? When I think about the future of packaging, one thing that gives me hope is that this is no longer a siloed conversation that people in packaging podcasts are talking about. The things that we're talking about have also been featured in Netflix documentaries. Tom Ford and Oprah are talking about it. It's more and more a common thread of understanding that we need to move away from plastic. That there are solutions on their way. And then as a result, it's like a flywheel of innovation that's being inspired and motivated by all the innovation that's already happening. So I have full faith that this generation, the following generation, subsequent generation are going to view the world differently. And it will become a part of culture that we value and think about materials. We design them responsibly and we don't let them become waste. That's what fuels me. I love that. I think that that's something that I'm hopeful— or we ask that question to every guest and every guest has had a different answer. And I think each answer I've agreed with. Lots of reason to be hopeful. Exactly. So thank you so much for joining us again. You were like someone who's been mentioned so many times. I'm excited that we got to make this work. We're excited for Sway and cheering you guys on as you guys continue to evolve. You guys have come so far since we started working with you guys. And so it's, it's great to see and we're excited to see where you guys go from here. Thank you, Brody. Thank you, Chris. Great to see you guys. Thanks for the time. Thanks, Julia. You know, that conversation was a long time coming. We keep talking about Julia, we talk about Sway, I feel like on all these different episodes. I'm really glad we got a chance to have her on and get to talk a little bit about what they're doing, how far they've evolved over the last few years. One thing that stood out to me from what we talked about was the importance of having something that performs performs, packaging that does more, essentially. You know, it has to perform, but also that you don't have to like compromise on your sustainability goals to be able to have a performance and sustainability at the same time. And even like the importance of like a drop-in replacement that's easy to use, not just from a marketing standpoint and this beautiful sustainability seaweed storytelling, but also the people who are using material or packing out product, they agree that they're in on it, they have a buy-in and agree that it's a good option and that they like it as well. And some of the things that stood out to me were really about how materials like this are really pushing the industry forward. I was glad to hear Giulia talking about cost. You know, early on it was all about how cool the materials, but sure, in the realities of what we go through every day, we know cost is the big factor. Absolutely. And it's exciting to hear that they're now getting into the range that makes this something that brands can choose without having to just make this be a big marketing push for a small portion of their business. It's also, I think, really about expanding what's possible, creating new pathways for how packaging can be sourced, designed, and scaled. Absolutely. You know, we're really grateful for Julia to sharing her perspective and the work that she's leading at Sway. So if you enjoyed this conversation, give us a follow, leave a 5-star rating, and share it with somebody who's working in packaging or sustainability. And if you're looking to explore how these kinds of innovations could apply to your own packaging, you can connect with us at the Sustainable Design Lab at Farative. And we can provide more insights, give you some product recommendations. So thanks for listening, and we'll see you next time.