Fertilizing new avocado trees should occur three times in the first year – once in March, once in July and again in October. When the tree becomes dormant in November, cease feeding. How much should you be feeding avocado plants? One tablespoon of nitrogen broadcast over the soil around the tree. Water the fertilizer in with a deep watering. The process for fertilizing avocado trees changes as they mature since they have changing nutritional needs. Continue to apply nitrogen, but in the tree’s second year, increase the amount of nitrogen fertilizer to ¼ pound divided into three applications. In its third year, the tree will need ½ pound of nitrogen and so on. As the tree grows, increase the amount of nitrogen by ¼ pound for each year of life divided into three applications. There is no need to fertilize the tree any more than this; in fact, it might harm the tree. It you had found that you had alkaline soil, the addition of peat moss will take some time to regulate the pH. So you will need to supplement with chelated iron. An iron deficiency should be patently obvious; the newest leaves will have green veins and yellow margins. Overall, no special avocado tree fertilizer is needed. A general use home fertilizer should work just fine. If it doesn’t contain zinc, you may wish to feed the tree with some zinc once a year. Keep the feeding to a minimum. Keep an eye on your tree for any other signs of distress such as disease and/or pests and treat immediately. Follow all of the above and you’ll be making guacamole in no time.
Read more at Gardening Know How: Avocado Tree Fertilizer: How To Fertilize Avocados http://www.gardeningknowhow.com/edible/fruits/avocado/how-to-fertilize-avocados.htm