What Is Compostable? Our Take On Compostable ProductsProducts like compostable knife or fork, available on our website, are labeled as certified compostable. This implies that these products are designed to break down into compost after disposal in a compost bin within180 days.A product or material is compostable when it can break down into compost after disposal. On the other hand, plastic disposable products often break down into microplastics and release toxins. But, compostable knife fork spoon turn into compost, making them a safe bet for our planet.