You are in Palm Beach County...I would NOT stop in September. Your trees will suffer if you don;t fertilize till spring (which we really don't have here in PBC. You can fertilize once per month with the 8-3-9 throughout the winter. If you are really concerned, you could lay off during December and January. Even with fertilizing, if it gets too cold the plants won't flush anyway.

pj1881, generally speaking it is okay to fertilize throughout the year in South Florida, however there are some variables to take into consideration. One such variable would be which species of plant you are considering fertilizing. For your tropicals, or if you are daring enough to try them, your ultra-tropicals, you should probably lay off the fertilizer in mid-October. You are already taking a chance in growing them in the first place, and you want to give them a chance to harden off before any potential cold blast arrives. A big danger, which applies to most non-temperate fruit trees, is that first cold front of the season when we have a big temperature drop from one day to the next, and if your tree is in active growth, it could die back considerably. (Don't forget that last year we had a cold blast the first week of November, so if you really want to play it safe, you may wish to hold off after September.) Older plants are more likely to survive cold weather better as the growth points on younger plants are more susceptible to cold damage. Also consider what physiological state the tree is in. If you suspect that the tree is about to flower (early season mangoes come to mind as flowering during out winters, not to mention lychee) then you do not want to fertilize during the flowering period. Hope this helps. BTW, I fertilized yesterday! :-)

Thanks fruit guy, those were my concerns. Effecting Lychee and Mango flowering by introducing Nitrogen moving into the winter. Whats the cut off time for 8-3-9 as to not effect flowering cycles? Also, I use a foliar spray Phyto-Fos that is super high in Phosphates as well as a nutritional complex spray as well. Do these help promote the fruiting cycle while avoiding the introduction of Nitrogen if used during the off months?

pj1881 I believe most people lay off a good 2 months before the anticipated flowering time (varies by cultivar), however I think it would be best to have Mr. Mango (Harry) weigh in as he has much more experience than I do. I have never used Phyto-Fos, so I will not be much help. While phosphorus generally speaking can promote flowering, I don't know that it is exclusive to that function, and whether or not it would be beneficial to do so during the winter months. If nobody else chimes in, you may wish to search on Google Scholar and see if there are any studies, or if there are not, perhaps you would care to contribute the fruit world knowledge bank on this issue?

Thanks for the moniker, Warren. Let's see if I can live up to it. First, let me say that I am no expert on fertilizing. I grow lots of mangoes but when it comes to fertilizers, nutritional sprays, etc., many of you know a heck of a lot more than me because I just don't use very much of them any more. From my memory, I believe I was taught (in the Sub Tropical Fruit Culture Class with Al Will) that fertilizer was optimally applied three times a year with the final application being in September. Applying after September did increase the risk of some types of trees (lychees come to mind) not properly flowering and fruiting. Back in the mid-90's when I took the class, it was well before the big "Nitrogen No No" theories became the rage. Al Will touted a 13-3-13 fertilizer with minor elements. I used that formulation for years while my trees were in the formative stages. Once they got to the size that I wanted them to be, I stopped fertilizing altogether. Now, it should be mentioned that my soil is a rich muck so I have seen no negative effect from the cessation of fertilization. Now I just have to concentrate on dealing with powdery mildew, sooty mold and anthracnose. Frankly, while some trees, like lychees, may not flower and fruit with fertilizer being untimely applied, I think mangoes are much less finicky. I think they will do fine even if you fertilize later than September. I hope this helps. Mr. Mango, indeed.

Harry