Marigold Calendula (Calendula officinalis L.) is an annual medicinal plant of Mediterranean origin which presents anti-inflammatory, antiviral and antigenotoxic properties. This species normally propagates through seeds, and the use of polystyrene trays is an economic way to produce its seedlings. Two experiments were carried out to evaluate the influence of two cell sizes of expanded polystyrene trays (40 cm³ and 12 cm³) and two substrates (soil + cattle manure and Plantmax® commercial substrate for vegetables) on marigold production and seedling quality. Experimental design in both assays was in randomized blocks, in a 2x2 factorial arrangement (two substrates and two cell sizes), with six replicates. Treatments regarding cell sizes were trays presenting 128 cells (40 cm³) and trays containing 288 cells (12 cm³). The used substrates were cerrado soil + cattle manure (1:1) and Plantmax® commercial substrate for vegetables. Part of the seedlings was transplanted to evaluate capitulum production. There were significant differences among substrates for total, root and shoot dry matter. The use of substrate containing cerrado soil and cattle manure led to the best development of marigold seedlings. However, the different types of substrates and polystyrene trays did not significantly influence capitulum production in transplanted seedlings.
medicinal plants; organic cultivation; seedling production; marigold
