Asparagus spears grow crooked when the growing shoot is damaged by insects (especially the asparagus beetle--see Asparagus Beetle and Spotted Asparagus Beetle), cultivation wounds on the crown, or windblown sand that pelts the tender shoots. The injured areas grow more slowly than the uninjured side, causing the stem to curve. Although the spears are misshapen, they are still edible.
Control asparagus beetles. To avoid wounding the crown, do not cultivate closer or deeper than 2 inches. Tall plants or fencing can be used as windbreaks to prevent sandblasting.