A Yukon educator says he's developed a new greenhouse kit that can add months to the northern growing season.

Bob Sharp says the "Solar Growing" greenhouse kit is the result of decades of research and development, and some support from the Yukon Research Centre. Now, he's starting to sell the 7-piece assembly kits.

"My son and I said, 'it's time we put them together as a kit, so people can put them up themselves'," Sharp said.

The greenhouses are designed to work in a northern climate, where temperatures can vary widely through a single day.

"Many of the greenhouses we either construct or purchase [in Yukon] have been developed in places like Vancouver, where you don't get such a big variation in daily temperature."

Sharp's design uses a bed of rocks under soil to absorb heat during a warm afternoon, and later release the heat inside, during the cooler evening and nighttime. He uses old computer fans to circulate the warm air, and automated vents to release any excess heat to the outside.

"It's just a way of managing the heat effectively," he said.

Sharp says he's able to grow tomatoes in his greenhouse from about June "until almost Halloween."

Three of the greenhouses are being installed at Whitehorse schools, for educational use. Others will be assembled at the school in Mayo and a day care in Carcross.