How often should zinc be applied to plants?

The frequency of zinc application depends on the method of correction, the soil type, and the needs of the plant. Foliar sprays are applied more frequently than soil treatments. Their difference in usage also depends on whether the program is intended for preventive or corrective purposes. Several factors can significantly influence the timing of reapplication, including soil pH, the organic content of the soil, and the timing of crop growth.

Apply foliar zinc sprays every 14 days when plants are actively growing. For the solution, the 0.1% zinc sulfate solution should be sprayed at dawn for best absorption. This process is considered an "immediate" but "temporary" correction, effective for 2-3 weeks. You can stop applications once any new growth appears to be normal in color. Avoid spraying during flowering to prevent damage to the buds.

Soil applications will be more effective in the long run than foliar applications. Zinc sulfate will have a longevity of 2 to 3 seasons if applied properly to the soil. Chelated zinc will have a 1- to 2-year availability if used in an alkaline soil. Organic choices, such as zinc-fortified compost, will slowly release nutrients over the seasons.

Preventive maintenance minimizes applications. In balanced soils (pH 6.0-6.5, 3% OM), biannual applications are usually all that is needed. Test your soil once every 2-3 years to adjust your schedule accordingly. Personally, I have kept orchard trees healthy for years through 3-year applications (with consistent tissue testing).

Over-application of zinc can cause toxicity, leaf bronzing, and other symptoms. Avoid applying zinc without soil testing when levels are above 3.0 mg/kg. Care should be taken to monitor runoff in sensitive areas to prevent potential environmental impacts: record application dates and rates to start optimizing your scheduling of future applications based on plant reaction.

Read the full article: Zinc Deficiency Plants: Symptoms and Solutions