TheGardenLady received this question from Jonathan.
I recently planted a 3-4 year old avocado tree which is now about 8ft tall. Since planting the leaf tips have been going brown and some leaves are very brittle, despite watering once or twice a day. Am I over watering? When I feel the earth around the tree it can be quite dry.
From reading your question, TheGardenLady cannot tell if you planted the avocado tree in a pot or out in the garden. If you planted the avocado tree in a pot, there may be too much salt gathering in the pot so you have to flush the pot out with lots of water. If it is grown in a pot it is best to give it frequent, light waterings with an occasional deep soak. Generally, the soil should be moist but not saturated. Yellowing leaves are a sign of over-watering; let the plant dry out for a few days. But if, as you described, the leaves turn brown and brown at the tips, too much salt has accumulated in the soil. Let water run freely into the pot and drain for several minutes.
But if you planted the tree in the soil without a pot, one of the most common problem of avocados is tip burn and marginal necrosis (death) caused by water stress and salinity, which is most prevalent during hot, dry weather according to this site. Proper watering is essential.
Even if you have good drainage, one can never tell if the ground is dry or wet just by looking at or feeling the top of the earth. Recommendations are to make a basin around the tree over the root ball that is kept filled with water.  See here. Also to have a device in the soil to see if the ground is really moist enough. Where avocados are planted on well-drained soil, it is better to give them water frequently than to try to keep them too dry. Read the link carefully for the recommendations on watering your avocado tree.