This is our fifth year of growing tomatoes in Alberta, a challenging and fun thing to do. This year we grew mainly heirloom tomatoes again.
I started all of the seedlings in just a little soil and replanted them as soon as they grew, always burying the stem. Mid-May I transplanted them into the green house. This are heirloom tomato varieties that grow in a northern, short growing season garden and greenhouse.
More on growing tomatoes: Instructions for Growing Tomatoes: in the garden and greenhouse