Avocado trees are warmth-loving, fruit-bearing trees that require special care in order to produce healthy, edible avocados. The avocado tree is a subtropical to tropical tree that has a varying frost-tolerance depending on the exact variety. The most common varieties of avocado trees include Mexican, Guatemalan and West Indian avocados. You'll need to practice proper watering, fertilising, weed control, pruning and cold protection.
Water your young avocado tree twice each week when there are five or more days of less than 1 inch of rainfall, soaking the soil thoroughly down to and around the roots. After the fourth year, water the avocado tree only once each week during prolonged dry periods from bloom through harvest.
Fertilise your avocado tree once every month or two months during the first year after planting it, applying 1/4-lb. of fertiliser per tree from early spring until early autumn. After the first year, apply 0.454kg. of fertiliser per avocado tree three to four times per year, increasing the fertiliser amount to 1 to 2 cups per 1 inch of trunk diameter thereafter.
Apply three to four foliar nutritional sprays to your avocado trees from spring through summer. The foliar spray should contain copper, boron, zinc and manganese for the first four or five years and, after that, a foliar spray containing only manganese, zinc and boron is necessary. Follow the application instructions on the label.
Maintain a weed- and grass-free area of 2 to 5 feet around your avocado tree's trunk. Spread a 2- to 6-inch-thick layer of organic mulch on the ground to cover this area, keeping the mulch about 8 to 12 inches away from the tree trunk. Don't apply herbicides to control weeds and grass around your avocado tree, because these chemicals can harm the tree.
Prune your avocado tree right after harvest if you have an early variety or in spring after all chance of frost has passed if you have a late variety. During the first two years after planting your avocado tree, prune to remove any branches that aren't growing laterally or close to a right angle. Afterward, prune your avocado tree annually, cutting back the tree to 10 or 15 feet in height and to cut any crowded branches back to the trunk.
Harvest your avocados when the fruit begins to mature. The avocados won't ripen on the tree, but instead they'll need three to eight days after picking to ripen. If you're unsure about whether the avocados are ready for picking, pick one avocado and see if it ripens properly within about eight days on your kitchen counter.
Plant avocado trees in extremely well-draining soil and in an area that has full sunlight and doesn't flood or have pooling water. Plant the tree on the south-facing or southeastern side of your house or a building for optimal protection from cold, if you live in a region that sometimes experiences frost or freezes. Keep the avocado tree about 8 to 10 feet away from the structure to give it enough space to grow. Space avocado trees 15 to 25 feet apart.
Protect your avocado tree when freezes or frosts threaten. Mound soil up around the tree's trunk to help prevent frost injury and ensure that the tree will survive a freeze. If you have a young avocado tree that's smaller, you can drape a blanket or tarp over the tree during the night and remove it in the morning.