COEUR d'ALENE - Ramsey Elementary third-grader Lash Laker invented an easy way to protect planted seeds, making sure they have the water and nutrients they need.

His invention, the "SeedBoard," is so good that he won the 2014 national "I Cubed Challenge." The invention perfectly addressed the competition's theme this year, "sustainability." The award was presented Tuesday after school.

"All the water gets sucked into the cardboard," said Lash, 8. "The cardboard also works as fertilizer."

The seeds are squeezed into the inner corrugated layer of the cardboard.

The seeds get water from the cardboard. He "glued" a mix of egg shell, coffee grounds and ash to the cardboard for nutrients to be extracted.

The cardboard is cut into roughly 1-inch-wide strips, which can be rolled out and buried.

Lash experimented with his invention, planting SeedBoard loaded with seeds into sand. It worked, showing it could help farmers planting in less than ideal conditions, possibly drought.

Cardboard is plentiful, it can be recycled, and SeedBoards are easy to use.

"We typed in 'sustainability' on the Internet browser, and said, 'Find something that looks interesting to you,'" said Lash's dad, Joel Laker, of Coeur d'Alene. "He started off with nothing like this."

"What stood out to (the judges) the most was he kept going back to the drawing table," said his mother, Annie Laker. "He kept improving it."

"I liked how you found ways to improve your project after each stage and ended up with a better solution for nutrient delivery," one judge wrote. "That's what inventors do."

He started work on his project last year.

"When I'm not inventing stuff I'm either doing homework, being at school or watching TV," he said. "I also know how to walk backwards."

Not surprisingly, he loves reading.

Beth Brubaker, who founded I Cubed with Diane Garmire, said hundreds of kids had the opportunity to participate in the competition, and judges from three states decided the winner.

"What we like to do is teach students to be problem-finders, and then to brainstorm solutions," Brubaker said.

Lash did a great job of matching his invention to this year's theme, said Brubaker, a Hayden Lake resident.

The popularity of the I Cubed Challenge is increasing as schools emphasize so-called "STEM" education, which includes science, technology, engineering and math.

"We would love to see it in a lot more states than just Idaho, Washington and Oregon," Garmire said.

I Cubed is based on the Invent Idaho student invention program.