The Comparative Performance of Plug Preparation Using Different Fertilizer Sources and Concentrations

Abstract

Plugs are crucial for initiating crop production in greenhouses, soil, and controlled environment agriculture (CEA). Vegetable, fruiting, ornamental, and other horticultural crops that utilize plugs for production have demonstrated superior transplant establishment rate, plant health, and total yield. The APS Laboratory for Sustainable Food at Florida Gulf Coast University investigated the quality of plugs grown based on different concentrations and fertigation sources using synthetic and organic sources. We carried out the growth of “Rex Butterhead” Lettuce ( Latuca sativa ) plugs with five different fertigation treatments, 1) full-strength synthetic starter fertilizer solution; 2) half-strength synthetic starter fertilizer solution; 3) full-strength organic starter fertilizer solution; 4) half-strength organic starter fertilizer solution, and 5) no fertilizer for control. Fertilizer treatments were formulated following manufacturer recommendations. The seeds were sown in Oasis ? Horticubes and saturated every day with the different fertilizer treatments. The plugs were cultivated for 15 days in a controlled environment until two leaves after the cotyledons had developed. After 15 days, we collected data which included wet weight (g), dry weight (g), leaf area (cm 2 ), and chlorophyll concentration (mg/cm 2 ). In addition, we derived data including the Leaf Area Index (LAI, cm 2 /cm 2 ) and Specific Leaf Area (SLA, cm 2 /g). Descriptive statistics were used to describe the biomass data. A Tukey’s HSD test was carried out to understand the differences between the fertilizer sources. We determined there was a statistically significant difference (P = 7.34E ? 29) in the measured plug growth parameters due to the various fertigation sources. We found that all fertilizer treatments produced viable plugs except for the control treatment. Of all the treatments, we concluded the half-strength organic treatment produced the more vigorous plugs with the greatest wet weight (g) and largest total leaf area (cm 2 ) which was statistically significantly different. Results from this study may inform growers about appropriate fertilizer options for plug production.