By Muhammad A. Shahid and KeAndre Leaks
Silicon (Si) is an emerging powerhouse in citrus production, offering wide-ranging benefits for plant health, fruit quality and stress resilience. While not traditionally considered essential, silicon was officially recognized as a “plant beneficial substance” in 2012 by the American Association of Plant Food Control Officials. Its inclusion as an approved input by the Organic Materials Review Institute (OMRI) has further paved the way for broader adoption.
Monosilicic acid is the only form of silicon that citrus plants can uptake and utilize. Unlike typical silicon accumulators such as rice or sugarcane, citrus is a non-accumulator, meaning it requires more strategic application. Research supports the use of both foliar and root (hybrid) applications to achieve optimum uptake and results.
BOUNTIFUL BENEFITS
University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) research trials on fresh-market citrus varieties like satsuma mandarins and red navel oranges have highlighted several improvements to plant and fruit quality with silicon supplementation. These include:
- Increased photosynthetic rate and leaf chlorophyll content
- Improved canopy growth and root architecture
- Enhanced fruit firmness, size and shelf life
- Greater nutrient-uptake efficiency
- Better post-freeze recovery and cold resilience
- Reduced fruit drop
- Improved Brix
- Reduction in leafminer damage
- Reduction in Asian citrus psyllid populations
Silicon plays a multidimensional role in citrus plant physiology. It reinforces plant cell walls, improving structural strength and reducing physical injury. It also enhances the plant’s natural defenses, inducing resistance against pathogens and increasing tolerance to climatic stresses such as drought, heat and freezing temperatures. In UF/IFAS trials, silicon-treated citrus trees not only showed quicker recovery from freeze events but also exhibited healthier overall growth and fewer pest attacks.
APPLICATION ADVICE
Various silicon products are available on the market. UF/IFAS recommends those with a high concentration of monosilicic acid, the plant-available form rather than products primarily containing silicon dioxide, which is not readily absorbed by plants. For best results, apply 150 to 200 parts per million of monosilicic acid in an alternating root and foliar application program, especially during active growth stages.
For foliar application, monosilicic acid can be applied using any conventional sprayer. For root application, it is effectively delivered through drip irrigation or microsprinkler systems. This integrated approach ensures efficient delivery of silicon to both shoots and roots for comprehensive plant benefits.
As citrus growers seek tools to improve productivity and manage stress, silicon is proving to be a valuable addition to the toolbox. Silicon offers a sustainable, OMRI-approved option that supports both tree health and marketable fruit quality.
Learn more on silicon use in citrus here.
Muhammad A. Shahid is an assistant professor, and KeAndre Leaks is an ag/food scientist, both at the UF/IFAS North Florida Research and Education Center in Quincy.
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