Low Substrate Copper Corrective Procedures
Brian E. Whipker, James L. Gibson, Paul V. Nelson, Todd
J. Cavins, and John M. Dole
Disclaimer: Growers should read and follow all label
directions. Test the corrective procedure on a small number of plants
prior to applying it to the entire crop.
|Not using a fertilizer containing copper
(eg. calcium nitrate + potassium nitrate).
1. Use a fertilizer that contains Cu.
2. Correct by applying a fungicidal spray containing copper, such
as tri-basic copper sulfate if needed.
3. Corrective drench application of copper sulfate at 9.3 ppm of
Cu for soilless substrates. Add 0.5 oz. (14.2 g) of copper sulfate
(25% Cu) per 100 gallons of water. Do not over apply. Rinse off
4. Foliar spray of Cu: mix 4 oz. (113.4 g) of tri-basic copper sulfate
per 100 gallons of water. It will give a final concentration of
159 ppm Cu. Test on a few plants first. Do not over apply.
Foliar sprays have a greater risk of plant injury. Avoid applications
during the midday heat. Plant uptake is enhanced by prolonged drying
time, which occurs during humid conditions, especially in the morning.
Nutrient uptake through the leaves is also greater in the day than
at night, making morning applications more desirable than evening
|Little or no copper provided through the irrigation
||1. Use a fertilizer which contains Cu.
|Don't forget to check out the Plant Root Zone Management
(PRZM) Manual for more information! Want to know more? Click
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