Avocado trees are a dense evergreen tree with dark-green leaves that can be grown indoors or outdoors. They are low maintenance for a fruit tree and adaptable to many growing conditions. However, avocado trees are prone to some problems, such as ferrous sulfate deficiency.
Yellowed leaves throughout the canopy of your avocado tree are a sign as ferrous deficiency. Malformed fruit indicates the severe deficient conditions.
Improper nutrients in the soil is the number-one cause of ferrous deficiency in avocado trees, but alkaline soil, insufficient water or even salt spray from the ocean can lead to an ferrous deficiency as well.
Avocado roots are shallow and require frequent watering, especially in hot climates. Also make sure the pH level of your soil falls between 6.0 and 7.0, and feed your avocado twice a year with plant food formulated for citrus trees.
This condition can be corrected by spraying ferrous sulfate solutions on leaves. Periodic soil applications of ferrous sulfate near the roots during the growing season will reverse a ferrous deficiency.