In general, foliar application is not very efficient (lots of loss).

How many plants are evolved to pull minerals from rain, versus pulling them from the ground?

Look around for palm-specific & FL-specific granular palm fert that will be slow-release and include chelated minerals. The stuff works well on more than just palms.

Probably $40 - $50 for a 40 lb. sack.

I see your point, BUT I also see a great difference overnight in my plants! I think maybe they have been somewhat iron deficient. Even though our well water is very high in Iron, I don't think they are utilizing it.

You can use this stuff as a soil drench too, you just mix it different. I will continue to use it til its gone. Then I will decide if I want to spend big bucks on a fertilizer you are talking about, or stick with this less expensive stuff which seems to work very well.

bihai I agree with you 1000% its amazing how soon you can see the effects. I bought a gallon of chelated liquid iron with mico nutrients. First on my sagos then on my lady palm , then ther rest of my palms ( and thats a long list ). I got a gallon for 20 dollars and its concentrated and I mix it with water properly. I have even started to get a more robust full growth from some of my palms. My trachy wagnerianus grew slow this summer few leaves and its on its second leaf since I used it on it 3 weeks ago

unautre, you are correct about it being inefficient, but often it is the only way to give leaves the nutrients they need.

Consider the case where the soil is not deficient in the minerals the plant needs, but they are unavailable to the plant for some other reason (pH too high, etc.) Foliar feeding can help with this problem, and as other people have mentioned already, the results can be dramatic.

I spray only a few of them and the rest I just pour it directly on the base of the trunk and it seems to work just as well.