To keep late-season poinsettias healthy, growers can follow plant production tips. Experts from North Carolina State University, including Clayton Humble, Patrick Veazie, and Brian E. Whipker, share best practices to prevent common problems.
One common nutritional issue is magnesium deficiency, which can develop when using 20-10-20 fertilizer in areas with low magnesium in the water source.
This type of deficiency can easily develop... especially when the Mg contribution from any dolomitic limestone leaches out of the pot over time.
Author's summary: Tips for healthy late-season poinsettias.