Planting as a houseplant
Start by washing an avocado seed, by using three toothpicks and suspend its broad end down over a glass of water so that it covers about one inch of the seed. Place the glass in a warm place, away from direct sunlight. Make sure to replenish water when necessary. Between two and six weeks, roots and stem should start to grow. When the stem reaches 6-7 inches in length, cut it to about 3. When the roots become thick and the stem again has leaves, plant it in rich humus soil, into a pot of 10 and a half inches in diameter. Leave the seed half exposed, and water it frequently. Occasionally, deep soak the plant. The soil should always be moist, but not completely saturated. The more sunlight you give the plant, the better. If your plant becomes yellow, over-watering may be the cause. Try to dry it for several days. If the leaves turn brown in color and fry at their tips, there is too much salt in the soil. You should let the water run freely into the pot and then drain it. When the stem reaches 12 inches, cut it to 6. This encourages growth.
Planting as a young tree
The best environment for avocado trees is moderately warm temperatures, between 60 F and 85 F, with moderate amounts of humidity. The trees tolerate temperatures of around 28 F to 32 F with only minimal damage. However, avoid freezing temperatures. Make sure to plant the tree between March and June. Sun damage may be an issue if you plant alters, because avocado trees do not absorb water well while young. In addition, you should plant the tree in a non-lawn area, away from sidewalks, ideally in a spot protected from frost and wind. Full sun is the best option for the tree. When planting, dig a hole as deep and wide as the root ball needs. Avocados are shallow-rooted trees, as most feeder roots are in the top 6 inches of soil. Therefore, good aeration is a must. The root system is sensitive, so great care should be taken in order not to disturb it. Loosen the soil and clip the circles of roots if the tree is root-bound.
Avocado trees prefer the pH of 6 to 6.5. If the soil is heavy clay, you should elevate the tree in a mound for better drainage. Make it 1-2 feet high and 3-5 feet wide. Do not put gravel or similar things in the hole. The tree will do the best if the roots get into the bulk soil soon after planting.
You should typically water the tree two to three times each week. When roots reach out into the soil, feel free to add more water while the frequency can diminish to once a week. This usually happens after one year. When watering, soak the soil well and allow it to dry out. Never allow the tree to get too dry. A mature tree needs about 20 gallons of water per day during the irrigation season. Seedlings require much less. Before watering, check the soil each time and make sure it dried a bit. If the soil holds the impression of the hand, it has enough water.
Mulching and Fertilizing
You should mulch with coarse yard mulch, as redwood bark, cocoa bean husks, and shredded tree bark all work. It should be woody and around 2 inches in diameter. Check your local garden-supply centers. When mulching, spread 20 pounds of gypsum around the base and make it 6 inches of mulch, while keeping the material about 6-8 inches from the trunk. With young avocado trees, use ½-1 pound of actual nitrogen per tree each year, and spread it with several applications. One other important nutrient is zinc, and ordinary home fertilizers normally work.
Other growing tips
Be patient with expecting and seeing fruit. With purchased and planted trees, expect the first fruit three to four years after you planted it. If you grow the tree from a seed, it can actually take from 5 to 13 years before the first fruit appears. When the tree flowers, expect many of them to fall without setting fruit. This is normal with the plant. Now that you know everything to try and plant your own avocado tree!