Effects of planting date and seedling age on agro-morphological characteristics, essential oil content and composition of German chamomile (Matricaria chamomilla L.) grown in Belgium

To date, little is known about the effect of certain cultivation practices on German chamomile (Matricaria chamomilla L.) in Belgium. The objective of the present study was to examine the effects of planting date and seedling age on agro-morphological characteristics, essential oil content and composition of German chamomile grown in Belgium. Treatments consisted of 4 different planting dates (15 April, 1 May, 15 May, 30 May) in combination with 5 seedling ages (30, 45, 60, 75 and 90 days) replicated thrice in a randomized complete block design. Planting date had significant effects on all of the agro-morphological characteristics. The highest values for them were obtained from the first date of planting whereas values decreased with later planting dates. Days after sowing (DAS) and transplanting (DAT) to flowering were significantly influenced by planting date and decreased with a later planting date. For 30-days-old seedlings, (E)-β-farnesene, α-bisabolol oxide A, α-bisabolone oxide and spathulenol were the compounds which were significantly influenced by planting date whereas the highest amounts were obtained for the latest planting date. Plant height and plant spread were the only agro-morphological characteristics which were significantly influenced by age of seedling at transplanting. Seedling age significantly increased DAS to flowering whereas the effect was age-dependent. For the first date of planting, spathulenol was the only compound which was significantly influenced by seedling age at transplanting whereas the highest amount was obtained for 90-days-old seedlings. The results of this study provide new knowledge to produce chamomile flowers of adequate quality in Belgium.