How big are these transplants when you're putting them out in the garden? If they're still tiny little seedlings in a seed-starting tray, they haven't much hope of surviving. Your best bet is to take an interim step. Once seedlings are about a month old, you carefully remove them from the seed-starting tray and pot them in individual containers to grow out another month or more before going outside. A simpler solution might be to use peat pots, since you don't have to disturb roots. Then, when you're ready to take them outdoors, let them acclimate to the weather over time, in a partly shaded area protected from winds. The north side of your house might be shady, but it also might be getting some dessicating winds, too.
Luke Miller, editor
Garden Ideas & Outdoor Living magazine