Two temperate foliose lichen species, Parmelia sulcata and Physcia adscendens, were grown outdoors on plastic cover slips to characterize development and study the environmental conditions suitable for development. It was found that aposymbiotic hyphal extensions that adhere to this substratum appeared within two weeks under favorable conditions and usually within five weeks. Pigmentation, rhizines, and epicortical development were seen within six months. The method and month of inoculation onto the cover slips had an impact on developmental success. Our results also suggest suitable combinations of humidity and temperature that may allow routine culture of these lichens in the laboratory setting.