PlantLife Online

Answer

Almost all fruit trees on the market today are grafts this way growers can have the best above ground with the best rootstocks below ground. However since you have had some fruit in the past this may not be the issue. Here are some general tips for growing avocado. Make sure you're planting location has good drainage, avocado trees like moist but well drained soil. Every few times you water it may help to water very heavy to leach excess salts from the soil. Like many other fruit trees avocado are heavy feeders, there are fertilizers specifically for avocados but any high nitrogen fruit tree formula would work. The fertilizer should be applied in spring and again in the summer. Mulch around the tree or allow leaves to stay on the ground as they drop. You may also need another tree to have a better chance of pollination. There are two types of avocado trees A and B one of each is need for cross-pollination. Avocados are generally heavy fruiters my guess is that it is a combination of the above which is causing the lack of fruit. Hope this helps.