I have the same problem. It is very frustrating - especially since many who don't have a serious infestation refuse to believe pill bugs eat live plants. They prefer decaying matter, but if they have a preference or haven't much else to eat, they'll come right for the plants.

Pill bugs require moisture so they will go after the moisture in the plants if the season is very dry. This is a common attraction, too.

The non chemical Spinosad helps me help my plants when pillbugs are a problem. It comes in a concentrated liquid form which I buy at my local farm store. Just follow the instructions. It is non toxic to humans, a natural product but also considered a broad spectrum so it might harm beneficial. Apply it during the hours where bees are not present. It also kills grub worms when used as a drench. However, it is not known to kill earthworms.

If you cannot find products with isolated spinosad ingredient, you can also use Sluggo Plus which contains spinosad as a secondary ingredient to the natural slug killer.