Greywater as a Viable Alternative for Irrigation of 10 Fall-planted Spring-flowering Geophytes Forced for Early Spring Flowering

The world population has topped 8 billion and water scarcity is rising because of the effects of climate change. The addition of plants to interior and exterior spaces has positive emotional, but questionable environmental, benefit when potable water sources are used for maintenance. To preserve potable water for human use, nonpotable resources, such as greywater, may be used as an alternative for the growth of ornamental plants. The purpose of the study was to determine the viability of using greywater for production of 10 fall-planted geophytes forced for early spring flowering. With very few exceptions, the application of greywater did not affect biomass accumulation, nutrient profile, or visual quality of the plant. Only fresh biomass of Allium and Hyacinthus was negatively affected by greywater, with no impacts on dry biomass or visual quality. There were also no negative impacts on plant survival, number of flowers, and flower duration as measured by time to flower senescence. There was an inconsistent effect of greywater irrigation on flowering time but was observed in only 1 of the 3 years for each of the cultivars affected. In the first year, greywater irrigation delayed flowering in Narcissus ‘Dutch Master’ and Tulipa ‘Parade’ an average of 7 and 6 days, respectively, whereas in year 3, greywater irrigation promoted flowering in Iris ×hollandica ‘Sapphire Beauty’ an average of 10 days earlier. Greywater appears to be a viable alternative for container-grown spring-flowering geophytes. This study adds to the body of research showing that greywater should be considered a serious alternative to freshwater for plant growth