Growth of the edible medicinal native species Crithmum maritimum L. on an extensive urban green roof is affected by substrate type and depth

Crithmum maritimum L. (Apiaceae), known as rock samphire, is a widespread native halophyte with narrow segmented bluish-green leaves and umbels of pale yellow flowers (July-October), which has been used since ancient years in human’s diet.
Considering the beneficial role of green roof technology in urban agriculture, the effect of substrate type and depth on growth of this species was investigated.
Ten-week-old plantlets were planted at the end of December 2015 in plastic containers (two plants per container) with a green roof infrastructure fitted (moisture retention and protection of an insulation mat, drainage layer and filter sheet) and placed on a fully exposed second floor flat roof at the Agricultural University of Athens.
Two types of substrate were used, grape marc compost:perlite:pumice (3:3:4, v/v) and grape marc compost: perlite: pumice: soil (3:3:2:2, v/v), as well as two substrate depths, 7.5 cm (shallow) and 15 cm (deep). Plants were regularly irrigated in the April-October period and their growth was evaluated monthly.
Half of the plants of each treatment were collected for further analysis at the end of August 2016 and the others at the end of May 2017. Eight months after the establishment (August 2016), during flowering, plants grown on deep substrates were taller (34-36 cm) than those on shallow substrates (29-32 cm), while no differences were observed in foliage diameter (37-43 cm) and number of flowering shoots per plant (21-27). Seventeen months after the establishment (May 2017), before flowering, both plant height and foliage diameter were greater on the deep substrates (25-26 cm and 34-35 cm, respectively) than on the shallow ones (20-21 cm and 26-27 cm, respectively). So, C. maritimum plantlets grew satisfactorily on an extensive urban Mediterranean green roof in all tested substrate types and depths, but the plant growth was enhanced by the deep substrate.

IV International Symposium on Horticulture in Europe – SHE2021

A.N. Martini, M. Papafotiou, K. Evangelopoulos

grape marc compost, perlite, pumice, soil, urban agriculture

https://doi.org/10.17660/ActaHortic.2021.1327.66