Significance Some plant cells, such as root hairs, pollen tubes, and moss protonemata, expand in a highly polarized manner known as tip growth. That calcium and actin play essential roles in tip growth has been well established, but how they interact with one another in vivo has mostly been modeled from in vitro studies. Here, we use a wavelet analysis approach to dissect the complex calcium homeostasis found in the moss Physcomitrella patens . By perturbing the actin cytoskeleton with drugs and targeted genome editing we find that the shortest calcium oscillation is directly coupled to actin dynamics. This approach to analyzing calcium oscillation profiles sets the stage for subtle dissection of the calcium–actin interaction mechanism.