I used to fertilize my trees with every watering, but I now have way too many trees to do that, so I started fertilizing on the 1st and the 15th day of each month, at 250 to 300 PPM N. Because my trees are in a year around warm greenhouse, I fertilize at the same rate every season of the year. I also like to use a 6 to 9 month slow release fertilizer along with the liquid fertilizer. This stops the feast and famine cycle of nutrition. Do what you want, but I would at least fertilize at 1/2 rate even during the winter. Sometimes during the winter, fruits dry out on the tree and drop if the tree is stressed too much. So for fruit development, and fruit maturity, higher temperatures and good leaf activity should be maintained. Irrigation with nutrient solution should be done in winter. - Millet (617-)