Growing Organic Avocados
Avocado trees are attractive, broad-leaved evergreens. The yellow-green flesh of the fruits is rich in oil and protein. They are easy to grow outdoors in most of California, Florida, and Texas. They also make attractive houseplants but will not bear fruit indoors.
Avocado trees mature to a height of 15 to 45 feet and are as wide as they are high, so give them plenty of space. Mexican types have dark, rough skins and are hardy to about 22° F. Guatemalan and West Indian hybrids have smooth, green skins and are less hardy. Not all cultivars are self-fertile; check pollination requirements before you plant. Ask your local independent nursery for further information about the variety that will grow best in your area.
Purchase a grafted tree and plant it slightly higher than it was growing, in the original container. Dig the hole twice as wide as the container size it is growing in. Use Dr. Earth<sup>®</sup> Planting Mix at a rate of 50% Planting Mix and % native soil, plus Dr. Earth<sup>®</sup> Starter Fertilizer, according to product directions. Choose full sun and very well-drained soil with a pH of 5.5-6.5. If you have poor drainage, plant your tree in a large raised bed or mound. Avoid windy locations, as the trees are prone to breakage.
Water young trees weekly, mature trees every other week or often enough to prevent wilting. If your water contains a lot of salts, flood the tree every fourth watering to flush out salt built-up and lessen possible root damage. Feed every other month with Dr. Earth<sup>®</sup> Fruit Tree Fertilizer to ensure a healthy and hardy crop. Apply a thick layer of organic mulch out to the drip line to conserve water and protect roots. Keep mulch one foot away from the trunk. If a young tree is not growing vigorously, an application of compost in early spring to midsummer is helpful. If new leaves yellow, have the soil tested. It may be a pH problem. Using a foliar fertilizer such as Dr. Earth<sup>®</sup> Liquid Solution will give the tree quick results.
Avocados need very little pruning. Pinch back upright shoots to control the height. Other than that, pruning will reduce yields and expose the trunk to sunburn damage.
The most common avocado problem is root rot. Symptoms include no new growth, very small fruit, and leaf yellowing and wilting. In advanced cases, a tree may die or survive in poor health for many years. Prevent root rot by providing good drainage and not over-watering. Avocados are sometimes attacked by fungal disease such as anthracnose, scab, and powdery mildew. They all thrive in high humidity. Control fungal diseases by spacing trees widely and trimming back surrounding trees to increase sunlight. Insects do very little damage to avocado trees, unless the tree is weakened by disease. Some cultivars naturally tend to fruit lightly, then heavily, in alternate years. Check with your local independent nursery for the best variety for your area.
Avocados bear in about three years. They ripen almost year-‘round, depending on cultivar and location. Avocados stay hard on the tree and soften only after they are picked. They are ready to harvest when they reach full size and the skin starts to change color. Pick one and let it sit indoors for a day or two. If the stem end doesn’t shrivel or turn dark, you can pick others the same size. You don’t need to pick them all at once, but don’t leave them on the tree too long or they'll begin to lose flavor. Harvest avocados by cutting the fruit from the tree, leaving a small piece of stem attached. Handle carefully to avoid bruising. Avocados are ready to eat when they yield slightly when squeezed.