The survey on phenological stages, the effect of nitrogen fertilizer levels and plant density and stage of flower harvest on flower production, active ingredients of Marigold(Calendula officinalis)

Marigold is a medicinal plant that has valuable ingredients which are used in the treatment of many diseases. The flowers of this plant can be used for the treatment of gastrointestinal disorders, skin ulcers and inflammation. Marigold accelerates skin wounds healing by preventing inflammation in the skin and mucous membranes, reducing tissue swelling and abscess re-built. Determination of the appropriate time to harvest the herb flowers is very important because it impact on the amount of active ingredients in flowers. In this study we aimed to determine the appropriate time to harvest the marigold flowers. I order to determine the amount of active ingredients (including extracts and essential oils) in flower and study the trend of changes, in three different stages of flowering, (including early, mid and late flowering, respectively, 90, 150 and 210 days after planting) sampling were done and the samples were sent to a lab to determine extracts and essential oils. The amount of essential oils determined by the method of steam distillation using Clevenger and the amount of extracts were determined by extraction with 70% ethanol method. In this experiment a total of seven phenological stages during marigold growth were diagnosed. Experimental data showed the positive effects of nitrogen fertilizer on increase of active ingredients of marigold. The results of experiment showed a significant different in amount of essential oil and extracts during the flowering season. Maximum production of essential oils and extracts obtained at early flowering and in the mid to late flowering season the amount of extracts and essential oils were reduced.