Crowdsourcing design has been applied in various areas of graphic design, software design, and product design. This paper draws on those experiences and research in diversity, creativity and motivation to present a process model for crowdsourcing experience design. Crowdsourcing experience design for volunteer online communities serves two purposes: to increase the motivation of participants by making them stakeholders in the success of the project, and to increase the creativity of the design by increasing the diversity of expertise beyond experts in experience design. Our process model for crowdsourcing design extends the meta-design architecture, where for online communities is designed to be iteratively re-designed by its users. We describe how our model has been deployed and adapted to a citizen science project where nature preserve visitors can participate in the design of a system called NatureNet. The major contribution of this paper is a model for crowdsourcing experience design and a case study of how we have deployed it for the design and development of NatureNet.