Scott, There's nothing quite like a cold frame for hardening off plants. It's not only prolonged sunlight that your plants have to adjust to, but also chillier temperatures and colder "feet" than they've experienced. Very dilute solutions of fish emulsion help with the adjustment. Putting the plants out in partial shade would be more gradual a treatment than even the cold frame. On sunny days, I wouldn't think twice about letting them "go out and play" while you're at work. Gradually move them from partial shade to more and more direct sun. Our friend, Byron Bromley waits until the ground is warm before transplanting, I usually only wait until overnight temperatures remain over 50 degrees. Although, until this year, I've only been transplanting Jalapenos and Hungarian Hot Waxes. My tomatoes and basils have sulked in the cool soil. When are they ready? Hard to tell, but they're probably ready when you no longer have the urge to supervise them outdoors. Gareth the ChillyKnight