How do I get rid of sow bugs? They are under every scrap of woody material and in roots.

Sowbugs commonly are found under piles of wood, rocks and among decaying vegetation. They like dark and moist areas. They don't do a lot of damage to plants unless there are very large numbers of them. A product called diatamaceous earth, marketed under various names, is very effective against them. Dust the material amongst them, and it has the effect of crawling over broken glass, not pleasant but non-toxic to humans. Alternatives include diazinon or sevin. Reducing the places where they feel comfortable is another possibility, removing the wood if possible.