Avocado trees are subtropical to tropical in nature, and need a warm location to be successful outdoors. Avocado trees can be grown indoors from seed for a good home science project, but for fruit production it is not as successful. Avocado seeds are usually hybrids, and do not grow true to variety. Trees grown from seed can take eight to 10 years to produce, and the fruit may be of poor quality. A more dependable method is to purchase a good-quality nursery plant. Grafted trees will produce quality fruit within two to three years of planting. Some varieties alternately bear, producing a large crop one year and a poor crop or no crop the following year.
Growing Avocado Seeds
Insert three or four toothpicks horizontally into the seed near the pointed end. Suspend the seed, pointed end up, over a glass of water with the bottom third of the seed submerged in the water.
Place the glass in a sunny location and add more water as needed. The seed will germinate in two to six weeks.
Pot the plant when the roots fill the glass. Place the plant in a 6- to 10-inch pot and cover the roots with sterile potting soil.
Cut off the top half of the plant when it reaches about 8 inches in height. When new branches reach 6 to 8 inches, remove the tip of the branch. Repeat this process until the branches develop into the desired fullness.
Transplanting an Avocado Tree
Choose a suitable location in a warm spot with protection from the wind and good drainage. In wet areas, create a large mound and plant the tree on top.
Choose a healthy grafted nursery tree. A 3-gallon tree that is 2 to 4 feet tall is ideal. Avoid root-bound trees. Check the tree for evidence of pests or disease and wounds or irregularities. Keep the tree watered well until planting.
Remove the grass from the area. Dig a large hole, at least three to four times the size of the tree's original pot.
Backfill the hole with the removed soil. Remove the tree from its pot carefully and place it into the hole so that the tree is planted at the same depth as it was in the pot. Fill in around the tree roots and firm the soil gently to remove air pockets.
Water the tree daily during the first week, then twice a week for the next two to three months and during dry spells.
Care for Avocado Trees
Fertilize the tree every 30 to 60 days during the first year. Apply 1/4 lb. of fertilizer per tree, increasing the amount, as the tree grows, to 1 lb. per tree. In subsequent years, fertilize three to four times per year.
Spray the tree with a nutritional spray of copper, zinc, manganese and boron three to four times a summer during the first five years. After five years, continue applications of zinc, manganese and boron. In alkaline soils, apply iron chelates during the late spring and summer.
Protect the tree from cold whenever a severe freeze is expected. Mound soil around the trunk for protection, and cover young trees with a tarp or plastic.
Prune young avocado trees to encourage branching and to shape the tree. Pruning of mature avocado trees is not necessary except to remove damaged or diseased branches.
Harvest avocados when the fruits mature. Avocados do not ripen on the tree. Mature fruits will ripen within a week on the counter top. Immature fruit do not ripen. Pick mature fruit as you need them. They can remain on the tree until the end of the season, when they will drop if they have not been picked.
About this Author
Diane Watkins has been writing since 1984, with experience in newspaper, newsletter and web content. She writes two electronic newsletters and content around the web. Watkins has a Bachelor of Science degree in chemistry from Clemson University. She has taken graduate courses in biochemistry and education.