Avocado trees are an interesting plant to grow. They can be started from seeds, or grown from cuttings taken from a mature plant. It can take up to fifteen years to get an avocado tree that is grown from seed to a size and age that it will bear fruit, but trees started from cuttings will usually bear fruit in three or four years. Pollination is also an important consideration. Although both male and female blooms are present on the same tree, they do not bloom at the same time. All of these things make growing avocados an interesting, and sometimes profitable occupation.
Avocados from Seed
You can start an avocado tree from any avocado pit, including those sold in the grocery store. This often a fun project for school children, since it can provide an opportunity to observe both roots and stem with leaves growing, especially if it is placed in a clear, glass jar. To grow an avocado from seed, use a sharp knife tip to start a hole on three sides of the seed. Firmly insert toothpicks or wooden matchsticks into the holes. Rest the wooden support sticks on the sides of a jar or glass, with the fat part of the seed immersed to about 1/3 of the seed in water. Place in a sunny window. After a week or two, roots will start to appear from the bottom and a stem with leaves will appear at the top. When this happens, you can gently pot the plant in a rich potting mix. Make sure to use a fairly large pot. This will make a pretty house plant that can be kept for several years. If you live in an area where the weather is warm, you can plant your baby tree outside in the garden. You should be aware, however, that avocados grown from seed do not breed true, so you are not likely to get the same kind of avocado as the fruit you purchased. Also, it takes at least ten years before a seed-grown tree will fruit.
Growing Avocados from Cuttings
Most commercial growers sell young trees that are grown from cuttings that are taken from a mature tree. This is because the cuttings will not only breed true, these young trees will usually bear fruit in three to five years because they are a clone of the mature tree.
To get a cutting, in early spring look for a healthy twig on which the leaf buds have not yet opened. Cut the twig at a 45-degree angle using a sharp pruning implement. On the cut end, gently wound the limb by cutting small nicks in the bark. Dip the end of the stick in IBA rooting compound and place it in a rich potting mix. Keep the soil moist but not soaking wet.
After two weeks, gently tug on the stick. If you get resistance, it is an indication that the cutting is putting down roots. At this point, you can repot it in a larger pot or, if you live in a warm climate area that has few frosts, you can plant it outside.
Another method of growing avocados is to graft the twig onto another rootstock. Since grafting has the greatest probability of success when it is done using a closely related rootstock, a desirable strain of avocado is often grafted onto a seed-grown baby tree.
Grafting is started similarly to growing trees from cuttings. In the spring, select a nicely grown twig on which the leaf buds are just beginning to open. Cut it on a 45-degree angle, and keep the twig moist before slipping it into a cut made in the bark of the rootstock tree. The cambium of the twig that is being grafted on should touch the cambium of the rootstock tree so that the two of them will grow together. After one or two weeks, white scar tissue should begin to appear, indicating that the graft is attaching itself, and that it is likely to “take.”
Remove all the leaves from the graft twig so that it will put its energy into attaching to the rootstock, rather than into leaf production.
Planting and Tending Young Avocado Trees
Once the seedling is started, care is similar whether it is grown from seed, a cutting or grafted root stock. In northern climates, the seedlings can be cultivated in pots. The size of the pot will help control the size of the tree. They make a very pretty foliage plant for indoors.
In southern areas, the seedling trees can be planted out of doors where they will grow into a tree as large as forty feet high. They need to be kept lightly moist, but not soaking, and they prefer a rich soil.