Hass Avocado trees are propagated through grafting, which means the stem of Hass avocado variety is spliced onto another avocado variety. The technique yields quicker harvests, consistent fruit quality, and disease-resistant avocado trees. Pollination, climate, soil, water, and diseases are among the variables that affect growing a healthy, fruitful avocado tree.
The condition most limiting to growing an avocado tree is cold weather. Hass Avocado seedlings varieties are the most cold-hardy, but they can tolerate cold temperatures to only about 20 degrees Fahrenheit. During freezing weather, it helps to drape blankets or tarps over a young tree and anchor the coverings to the ground. If an avocado tree is large, then mounding soil or mulch high on the tree trunk for winter can help the tree survive cold temperatures.
An avocado tree can grow successfully in a variety of soil types and in soil with acidic or alkaline pH levels, but the tree requires soil that has good drainage. It declines in poorly draining and saline soil. Although an avocado tree cannot tolerate wet soil, it needs at least 1 inch of water every week during periods of insufficient rainfall. Not fertilizing the tree until it is 1 year old is recommended. Young trees need four applications of balanced manure and older trees need twice-yearly applications of a high-nitrogen product applied in early December and late July.