Am I reading these palm signals correctly?

[FishEyeAquaculture]

Just making sure I am looking at what I think I’m looking at, these palms are telling me they’re experiencing magnesium deficiency (and potassium deficiency?), right?

If so, we fertilize twice a year with Florikan 8-2-12 180 Day Palm Blend making sure to also include either Florikan MEG-IRON V or SouthernAg Essential Minor Elements Granular Formulation (whichever is easiest to acquire).  
Other than the fact that we have had over 60” of rainfall so far this year, is there something else I am missing?

Pictures are of a Mule and C. baileyana

 

[tim_brissy_13]

I’m usually really poor at identifying the different types of deficiency in palms, but to me your C Baileyana looks pretty good. Is the spotting only on the lower leaves? The new growth looks really healthy and the lower frond may just be going through potassium relocation. 

[Steve in Florida]

Could that black spotting be mold issues?

[Jim in Los Altos]

Classic potassium deficiency. Lutz Potassium stakes work very well for this malady. 

[sonoranfans]

I see no deficiency in the bailey, just mold spot.  Older leaves do yellow as the palm withdraws the chlorophyll after it begins to abandons the leaf.  On the mule I just see some yellowing on the older leaves, so might be no issue at all.  Potassium deficiency happens from leaflet tip first then moves toward the petiole and it appears as blotchy, not smooth discoloration.  This is because potassium is fixed(positionally) in the leaf, unlike magnesium.  With Mg deficiency, the whole leaf turns yellowish except the veins.  Not sure why you have mold spot on that bailey.  That kind of mold spot never leaves the leaf, they tell you to cut the leaf off it it gets on the leaflets  Sometimes coming out of winter here in florida I have seen that mold spot on small palms near the ground(bismarckia etc).  Fertilizer spikes dont work well in our sandy soil, use sulpomag and spread it around the root zone.  The fertilizer spike assumes you have faster capillary action sideways than drainage downwards and they dont hold up in heavy rain, they get washed away.  Here in my area of florida the drainage is high so spike only fertilize a small cylindrical volume and all the rain makes them almost useless.  I also use the 8-2-12 florikan but I overlap the applications.  Every 3-4 months in the growing season I put some florikan down as the nutrient release peaks, as by month 5-6 not much being delivered and if that occurs in the growing season it could lead to a deficiency.  Sulpomag is also part fast and part slow release nutrient product as some of the potassium is not fully water soluble.   I apply sulpomag to already deficient palms and also extra for my copernicia bailey and fallensis as they are potassium pigs. I do generally use sulpomag only outside the july-oct rainy season though.  Our rains just wash away a good a good part of any non controlled release fertilizer.  I couldn't keep my bailey out of deficiency with slow release sulfur coated lesco, even with application every 2 months.  

[akamu]

Sulpomag is great stuff for pritchardia also . Plus the sulfur is anti fungal.