Comparison of Automated Controller Settings for Irrigation and Fertilizer Needs of Potted Geranium

The future of agricultural water availability is threatened by climate change, population growth, and environmental regulations. Most of the global water is being used for crop irrigation. The objective of this research was to determine optimum timer-based controller settings and controlled-released fertilizer rates for ‘American Red’ ( Pelargoium ×hortorum ) potted geranium plants. Fertilizer was top-dressed at 3, 6, or 9 g. Plants were irrigated by a timer-based controller set to water at 11:00 AM every other day for 2 minutes, 9:00 AM and 2:00 PM for 1 minute per day, 11:00 AM for 1 minute per day, 11:00 AM for 2 minutes per day, and a control of manual hand watering. Data regarding plant growth, soil and leaf nutrients, and water use were collected. For geranium growth factors, the total flowers per plant was greatest for irrigation at 11:00 AM for 1 minute with 6 g fertilizer. Plant height and shoot dry weight were greatest for 6 and 9 g fertilizer. The number of umbels and soil plant analysis development (SPAD) chlorophyll meter readings were greatest for 9 g fertilizer. For geranium soil nutrient content, the pH was greatest for 3 g fertilizer, whereas the electrical conductivity, potassium, nitrate, sulfate, and boron were greatest for 6 and 9 g fertilizer. Regarding the nutrient content of the leaves, total nitrogen, boron, iron, and copper were greatest for 9 g fertilizer. Water use efficiency was greatest with 6 and 9 g fertilizer and irrigation 1 minute per day at 11:00 AM. The findings indicated that using timer-based controlled irrigation systems programmed to water for 1 minute during the morning with 6 g fertilizer resulted in plants that not only reduced water consumption but also enhanced water use efficiency and overall plant quality.