The 2009 ASHS Annual Conference

Two separate experiments were conducted to evaluate the growth and flowering responses of container-grown greenhouse marigold plants to four rates of two non-composted broiler chicken litter-based organic fertilizers 4-2-2 at 1%, 2%, 4%, and 6% (by volume) and 3-3-3 at 1.34%, 2.67%, 5.34%, and 8.0% (by volume) and a commonly used synthetic controlled-release fertilizer 14-14-14 at 0.99, 1.98, 3.96, and 5.94 kg·m^-3. For the fertilizer rates used in this study, in general, increasing 14-14-14 fertilizer rate increased plant growth and flowering performance. However, low to intermediate rates of 4-2-2 and 3-3-3 produced the highest plant growth index, shoot dry weight, number of flowers per plant, total flower dry weight, and root rating. Plants grown in high rates of 4-2-2 and 3-3-3 showed symptoms associated with excessive fertilizer. Results from this study indicated that 4-2-2 and 3-3-3 have the potential to be used as organic fertilizer sources for container production of marigolds in greenhouses. However, growers need to be cautious with the rate applied. Since different crops may respond differently to these natural fertilizers, it is important for growers to test new fertilizers before incorporating them into their production practices.