The influence of substrate type and chlormequat on the growth and flowering of marigold (Tagetes L.)

This study was conducted to investigate the effect of various horticultural substrates (compost, peat-coconut, peat TS1, flower soil, lowmoor peat) and a foliar spray of chlormequat (at a concentration of 1380 mg dm^-3) on the growth and flowering of the marigold cultivars belonging to two species: Tagetes erecta - ʻMarvel Mixtureʼ and ʻTaishan Orangeʼ, and Tagetes patula - ʻDurango Redʼ and ʻBonanza Flameʼ. The obtained results show that the plants grown in peat TS1 and peat-coconut were taller, had longer internodes and leaves, and thicker stems than the plants grown in the other substrates. Chlormequat significantly reduced the height of ʻMarvel Mixtureʼ (in peat TS1), ʻTaishan Orangeʼ (in lowmoor peat) and ‘Bonanza Flameʼ (in peat-coconut). The use of chlormequat also accelerated the development of flower heads in ʻTaishan Orangeʼ (in lowmoor peat).