A collaboration between students and Danish entrepreneurs has produced pencils that can grow into flowering plants, herbs, and vegetables.

When the writing portion of the pencil is worn-down, you simply put the “eraser-end” (which is actually a seed capsule) in a pot with soil. Eventually, after enough water and sunlight, a plant will sprout. The sprout pencils come with a variety of seeds, including sunflower, mint, lavender, cherry tomato, sweet pea, and wild strawberry.

The pencils are made of sustainably sourced cedar wood, with the pigmented core made of a mixture of clay and graphite. The seed pod is also made of cellulose, meaning the whole pencil is non-toxic and safe for kids to use. To curb their carbon emissions, the company source all their materials locally, with two different production models for their two main markets, Europe and North America.

The idea was originally developed by three students at Massachusetts Institute of Technology in 2012. After a Kickstarter crowdfunding campaign, the project caught the eye of Danish sustainability consultant Michael Stausholm. After signing a deal with the students, his new company launched in June 2013.

Just a few years on and more than 450,000 pencils are sold a month to more than 60 different countries, according to their site. The company has also attracted a large amount of patrons to switch out – at least temporarily – their ballpoint pens, including Ikea, Bank of America, the World Wildlife Fund, TedX, and even the Vatican.

“One of the major strengths of Sprout pencils is their capacity to pull such a complex issue as sustainability down to earth,” Michael Stausholm, founder of Sprout World, said in a statement.

He added: “One of our important tasks is to make sustainability pragmatic and comprehensible – but, most of all, fun. Our plantable pencils and paper are perfect for spotlighting the reuse of the Earth’s resources. We’re talking micro level, but we’ve all got to start somewhere.”