Tips for dividing hostas include dividing in spring or fall, watering the ground first, cutting as few roots as possible, and replanting the divisions at the same depth. Digging around the hosta plant and lifting it out of the ground makes it easier to divide the plant without cutting eyes.
Dividing hostas can set back the maturity of the plant, so only divide them when necessary. In spring, divide hostas after the eyes pop up but before they unfurl. For fall divisions, September or October is ideal when the weather is cool and damp. If it hasn't rained in a while, watering the soil the day before prepares the hosta plant for division.
A straight spade is an option for cutting through the clump to divide it into thirds or quarters. For smaller divisions, shaking off as much soil as possible and cutting with a sharp knife allows for more precise cuts.