How do I prevent frost damage?

Location, location, location...

When planting stone fruits in Canada, it's good to consider the fact that while the trees are hardy, they tend to bloom inconveniently early and can wind up blooming during a frost. This can cause considerably or complete failure of the trees to then produce fruit. So let's think about how frost and trees work within a landscape:

• Frost settles. So plant tender fruits on higher ground. Not so high they are completely open to the elements, but avoid valleys. Preferably somewhere with reasonable airflow, so the frost can't settle.
• Plant on the north side of a bush/building/barrier. This will prevent the tree from warming up unseasonable early in spring, pushing it's dormancy period longer, until hopefully the risk of frost has passed.

Mechanical and chemical preventative measures

Perhaps not for the casual orchardist, but for those more motivated, consider frost comes out to play on clear nights, still nights. Large fans, overhead misters/sprinklers, or even sheets (particularly for a backyard dwarf orchard) may be draped over trees to prevent the frost from touching the blossoms, and Christmas lights could be hung for a touch of additional heat (and cheer!).

Spraying liquid seaweed can also help increase a plants tolerance of frost, read about how and why on page 3 and 4 HERE.