Effects of layered artificial substrates on marigold plant growth and production

Marigold (Tagetes spp.) is one of the most commonly grown bed and pot annual ornamental flowering plants. Bed (or container, pot) plants need a potting medium, an artificial substrate that provides support, aeration, moisture, and nutrients. There are four common substrates of potting media; peat moss (PM), perlite (P), vermiculite (V), and sand (S). The objectives of this study were to: (i) investigate the effects of layering artificial substrates on marigold plant growth and flower production, and (ii) explore the best combination of layered media. Seedlings were grown in a layered potting media as well as in mixed potting media. Shoot height, size and number of flower, root length, and fresh and dry weight of shoots and roots were measured. Results showed that regardless to the layering, (V-P-V) combination media was the best for growing marigold, whereas plants grown in (PM-S-PM) layered media had the least growth and flowering. Overall, marigold grown in layered media did better than the ones in mixed media, and the (V-P-V) and (V-P-PM) arrangements of the substrates (from top to bottom) produced the best plant growth and flower production.