This experiment was conducted to identify the effect of fertilizer type and concentration on the growth of petunia 'Soft Pink' in C-channel sub-irrigation system. There are two types of fertilizer such as water soluble fertilizer(WSF, Technigro. 20-18-20, Sungro Co., USA) and slow release fertilizer(SRF, Osmocote, 14-14-14, Scotts Co., Netheeland) and three methods of irrigation such as wick and mat irrigation using sub-irrigation and overhand irrigation. In case of fertilizer, Plants supplied with WSF showed the higher growth in plant height, branch number, fresh and dry weight than those of with SRF. But the results of leaf length and width were reverse. In case of irrigation method, the sub-irrigation system was more better in plant height, branch number, fresh and dry weight than those of with overhand irrigation, but leaf length and width were not. 1.5 g/L of WSF with mat-irrigation system showed the highest quality with 42.7cm of plant height, 7.86cm of leaf length, 5.31cm of leaf width, and 144.1g of fresh weight, respectively. In wick-irrigation system supplied with WSF, 1.5 g/L treatment also showed the highest quality as well. WSF increased the number of flower, the number of flower rapidly increased at 20th day after first blooming day. The contents of N and K were the highest with WSF in sub-irrigation system. The contents of Ca and Mg were more higher with overhand irrigation than those of with sub-irrigation system, and with WSF showed the higher content in Ca and Mg than those of with SRF.