Q: When's the best time to rototill my garden? —Maryanne Collins, Islip, N.Y.
A: You may not need to rototill at all. If your soil has the right pH, a good balance of organic matter, and is light and fluffy, a power tiller or a manual cultivator, like the one shown at left, can actually wreck the soil's structure and reduce its fertility. But if a soil test shows that amendments have to be added, tilling does make sense. Till when the soil is damp, not wet or dry. Just squeeze some in your hand. If it holds its shape when you open your fist, it's too wet. If it crumbles, it's too dry. If it cracks apart, it's ready to cultivate.