Food

Notes and links to Wikipedia pagesGuatemalan, Mexican or West Indian Avocado

Known for its large, dark-green oval leaves and bumpy, mellow-tasting green fruit, the avocado tree (Persea americana) has value in the landscape beyond fruit production. Its medium-sized upright habit and evergreen foliage creates a contrast against fine-leafed deciduous and coniferous shrubs and trees. When planted in the correct location, an avocado tree will thrive and benefit your home garden.
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Each variety of avocado falls into one of three groups: Guatemalan, Mexican or West Indian. The names of the groups signal where an avocado variety originated from or first grew. Over time, commercial growers crossed different varieties from each group to create disease-resistant hybrids. Although these new, hybrid varieties do not directly come from one of the original three countries, their lineage is traceable back through the parent plants that their classifications come from. Each group is slightly different in growth habit, fruit shape and size, harvest time and climactic requirements.
Temperature
Depending upon the variety, avocados grow in U.S. Department of Agriculture plant hardiness zones 8 through 11. The most cold hardy of the three types is the Mexican avocado, which will grow in temperatures as low as 19 to 20 degrees Fahrenheit. Because of their cold tolerance, they classify as subtropical trees. West Indian varieties tolerate the least amount of cold, with a lowest surviving temperature of 33 F. The Guatemalan falls in between the first two varieties by surviving temperatures of 26 to 30 degrees F. Both the West Indian and Guatemalan varieties classify as tropical trees.
Culture
Avocado trees grow best when planted in warm areas of the garden that receive full sunlight for at least 6 to 8 hours per day. These trees will grow in part shade, but without full sunlight they will produce little to no fruit. They grow well in almost any soil type as long as it is fast draining and has a pH of 6 to 7. Because of their tropical nature, avocado trees require frequent, deep watering. The soil needs to dry between applications of water to allow the roots access to sufficient oxygen and to prevent rot.
Special Considerations
Avocado trees require horizontal spacing of 20 feet to accommodate their mature spread, and 30 to 60 feet of vertical space for height. Avocados grow best when humidity levels are high. Locate the tree in an area sheltered from high winds but open to slight breezes. High winds may break off branches and fruit and will surely decrease humidity, but some air circulation is required to stop fungal diseases from forming.

Avocados (Persea spp.) are evergreen trees that grow delicious green fruit that surrounds a large pit or seed. Avocados grow in the warmest regions of the United States. You can propagate trees from seed, but to do so results in trees that vary in quality and quantity of fruit. For these reasons, budding and grafting are common methods of propagation. Planted during spring, avocado trees thrive in U.S. Department of Agriculture hardiness plant zones 10 and 11.
When to Plant Avocados
"Hass" avocado trees are planted when the ground is warm, generally during the months of March through June. Trees planted in summer often falter because young tree roots cannot take up water well. If you do plant them during summer months, take certain precautions, such as deep watering during dry spells and protecting them from hot summer sun. Whitewashing the avocado tree trunk and branches can help protect trees from too much sun. Avocado seeds are the result of cross-pollination and do not produce true cultivars. So, the seed from a "Hass" avocado does not produce the same tree, but something else.
Planting Spacing and Temperatures
"Hass" avocado trees need full sun to be productive, but they can grow in shaded areas. Plants require spacing of about 20 feet from other avocado trees and other plants. Avocado roots often compete with other plant roots for moisture and nutrients. Trees thrive in temperatures between 60 and 85 degrees Fahrenheit during the day, but once established, the trees can withstand temperatures between 28 and 32 degrees Fahrenheit with only minimal damage.
Temperature for Fruit Set
Avocado trees require a second tree to ensure good fruit production, but temperature also affects fruit set. The optimum temperature for "Hass" fruit set is between 65 and 75 degrees F. When temperatures are cooler or warmer, it affects fruit set because trees can produce fruit from flowers that did not receive proper pollination. If this occurs, the fruit is generally smaller, elongated fruit called "cukes." The "cukes" often drop from the tree, but if they do not, you can pick and eat them.
Time from Planting to Production
Avocado tree production depends on whether you planted a nursery plant or it was started from seed. Avocado trees started from a nursery tree generally begin setting fruit three to four years after planting. Trees grown from seed take longer and require between five to 13 years before setting fruit. When the avocado tree does begin to flower, it is normal for many of those first blooms to fall off the tree.

Avocado trees' (Persea sp.) native distribution is southern Mexico, according to the California Rare Fruit Growers, and they do not do well in very cold temperatures. Even an overnight cold snap can harm your trees, especially if they are unprotected or very young. You can avoid frost damage by selecting the most cold-hardy varieties of avocado and growing them in a space that is protected from cold winter winds.
Types and Hardiness
There are three main types of avocados, named for their places of origin: Mexican avocados (Persea americana var. drymifolia), West Indian (Persea americana var. americana) and Guatemalan avocados (Persea nubigena var. guatemalensis). The U.S. Department of Agriculture plant hardiness zones for avocado varieties are 8 through 11, if you have a protected place in your garden.
Cold Tolerance
The cold tolerance of avocados depends on the variety. If you experience regular, light freezes every year, Mexican avocados are your best option because varieties like "Bacon," "Mexicola" and "Topa Topa" can survive temperatures down to 25 degrees Fahrenheit. If you rarely have freezing weather, you might be able to grow a Guatemalan variety like "MacArthur," "Rincon" or "Nabal," which can withstand temperatures down to 29 F. Less-hardy Guatemalan avocados like "Anaheim," "Carlsbad" or "Hellen," can be damaged when temperatures drop below 30 F. If you never have freezing weather, you might be able to grow especially tender West Indies avocado varieties, like "Pollack," which can be damaged by temperatures at freezing or below.
Cold Protection
If cold weather that could potentially damage your avocados is forecast, plan ahead to prevent cold damage. For young, small avocado trees, support a heavy blanket from a frame around the tree. If you have an older tree, incandescent outdoor Christmas lights can help to keep the tree warm. Before a freeze, the California Rare Fruit Growers recommends that you harvest any fruit that remains on the tree to prevent it from being ruined.
Cold Damage Recovery
After a freeze, you might be able to salvage your avocado tree. The blooms that fell off from the cold will usually grow back, according to the University of California Agriculture and Natural Resources. Adequate watering throughout the cold weather season will help to minimize the drying effects of frost. If more freezing weather is predicted for the next few weeks, do not prune off freeze-damaged limbs. Once all chance of sub-freezing temperatures has passed, prune off the dead material.
Content from http://homeguides.sfgate.com for my personal study.

Avocados Persea Americana
Avocados are considered a tropical fruit, grown commercially in California, Mexico, and extreme south Florida near Homestead. However, varieties discovered in the mountains of Mexico have considerable cold resistance, and will survive temperatures into the mid teens to low 20s, especially if grown in a protected location. At the University of Florida campus, as every agriculture student remembers, there was a medium sized dark-skinned avocado (known as 'Gainesville') that ripened every year next to Hume Library (where we all studied), and was sought after by both the students in the know and squirrels! We grow a number of varieties of cold hardy Avocados, that are adapted to Zones 8-10, from coastal SC to TX!
Cold Protection
Make sure you plant them on the south face of a building, or underneath overhead canopy, much like protecting citrus. Avocado trees in the home landscape should be planted 25 to 30 feet apart or more. Placing freeze cloth over them during hard freezes also helps protect them. Another helpful technique is to mulch the plant above the graft union, so that it protects the rootstock and the graft from cold air (soil is warmer than air). The coldest temperatures listed per avocado variety depend on winter weather conditions. Some conditions such as age of the tree, elevation, moisture levels, relative humidity and wind speed can result in a variance of the temperatures listed. Please protect all young plants during temperatures in the mid 40's. Consider maintaining the height of your avocado tree to 20' x 20' to make an easier fruit harvest and to provide winter protection. Cold Temperature known to live: Mature 15 - 28° Young 30 - 32°
Planting site
Your planting site selection should be well-drained, non-low lying area, sandy loam soils with. Full sun is required for fruit production minimum of 6 hours of full sun. Prepare the area by removing any weeds prior to planting. This step is often over looked but is absolutely critical to any successful planting. Weeds and grass steal light, water and nutrients from your trees.
Soils
Avocado trees do not tolerate flooding or poorly drained soils but are adapted to many types of well-drained soils. Continuously wet or flooded conditions often result in decreased growth and yields, nutrient deficiency symptoms, dieback, and sometimes tree death. Under these conditions, trees are highly susceptible to root infection by Phytophthora fungi. Trees grow well and produce satisfactory yields in the sandy and limestone soils of Florida if not subjected to flooding or poor drainage. In the home landscape, select an area that does not flood. If there is a potential for excessively wet or flooded soil conditions plant on a large hill or mound made up of native soil, 2 to 4 ft high (0.6 to 1.2 m) by 4 to 6 ft diameter (1.2 to 1.8 m).
Planting
Dig the hole twice as wide as the pot but no deeper than the root-ball. Do not add soil amendments to the soil such as compost, peat,mulch or organic matter, this acts like a sponge and increases root rot and robs the trees of nitrogen from the fertilizer (microbes breaking down the organic matter use nitrogen in the process). Also, do not use fertilizer, potting soil, or chemicals on your young trees. Carefully remove the tree from the pot keeping the soil around the roots intact. It helps to tap the outside of the container to loosen the edge. Do not yank the tree out of the container as this can separate the roots from the tree. Carefully separate the roots if they are root bound. Plant the tree at the same height they were grown in the pot, not deeper. Partially fill in the planting hole with the native soil. Set the tree in the middle of the hole. Avoid planting the tree too deep. Using some soil, secure the tree in a straight position, then fill with native soil and firming the soil around the lower roots making sure there are no air pockets. Keep back-filling until the soil is above the root collar. We recommend creating a water-holding basin around the hole and water the trees in thoroughly at planting. Remove the berm at the end of the second growing season. Water slowly at the drip-line. Water in thoroughly, making sure there are no air pockets around the roots. Air pockets prevent roots from growing into the soil around it. After the water has soaked in, spread a protective layer of mulch 2-4" deep around the trunk pulling the mulch a few inches away from the trunk for good air circulation. Choices for mulch, leaf litter, hay, shredded or fine bark, pine needles or use weed mats to prevent weed competition. Remove the pot stake that came with the tree. If the tree appears stable staking is not needed. If using Grow Tubes then staking the tree is not necessary. If staking is necessary, hold the trunk with one hand to find the height at which the unsupported top can stand up on its own and will spring back to a vertical position if lightly flexed. Allow trees a slight amount of flex rather than holding them rigidly in place. Tree straps should be made of material that will not injure or girdle the tree.
Fertilization
Avocado trees should be fed on a regular basis after their first year of growing in the ground or in a container. Fertilize using well balanced citrus / avocado food at least 4 times per year and as often as once a month. You can try Espoma Citrus Tone & Avocado variety fertilizer. Remember that avocado trees that have been well feed year-round are better able to deal with cold temperatures in the winter.
Water
Avocados prefer infrequent deep root waterings. Do not over water avocado trees! Over watering is often the number one factor in causing root rot to develop in the first place. It is best to allow trees to dry out before you apply water again. In most cases, avocados will not need to be watered during the winter. However it is important to water in the winter if there are prolonged periods without rain. It is a good idea to apply a 3 to 4 inch layer of mulch to avocado trees each year to help retain soil moisture and improve soil quality. Apply mulch in spring and fall spreading it out 2 to 3 feet from the trunk of the tree.
Pruning
Formative pruning during the first 2 years may be desirable to encourage lateral branching and growth. After several years of production it is desirable to cut back the tops of the trees to 10 to 15 feet (3.1 to 4.6 m). Selectively removing a few upper limbs back to their origin (crotches) each year will help prevent the loss of the lower tree canopy due to shading by the upper canopy. In addition, maintaining a smaller tree facilitates tree care and fruit harvest, makes it easier to spray the tree, and greatly reduces possible storm damage. Do not remove lower tree branches. Pruning should be done soon after harvest for early varieties, but after danger of frost has passed for late varieties. Severe pruning is sometimes used to reduce tree height or width of very large trees. It does not injure avocado trees, but reduces fruit production for one to several seasons.

Avocados trees are classified 'A' or 'B' type. An 'A' or 'B' will produce by itself, but avocado trees produce heavier crops when an 'A' and a 'B' type are planted in close proximity.

Avocados will begin to bear fruit within 3-4yrs of age.
Tree Form: Central leader
Height: 30-50' (depending on type)
Pollination: Self-pollinating
Flowers: January- April
Bears: June-March (depending on type) Within 3-4 yrs of age.
Light requirements: Full sun
Soil type: Well-drained, non- low lying areas.
Fertilization: After planting, wait about a month before fertilizing. Fertilizer mixtures containing 6 to 10% nitrogen, 6 to 10% available phosphorus petnoxide, 6 to 10% potash, and 4 to 6% magnesium give satisfactory results with young trees.
Watering: Newly planted avocado trees should be watered at planting and every other day for the first week or so and then 1 to 2 times a week for the first couple of months. During prolonged dry periods (e.g., 5 or more days of little to no rainfall) newly planted and young avocado trees (first 3 years) should be well watered twice a week.
Maintenance: Easy
USDA Hardiness Zone: 8-10

Item #: Brogdon Avocado - Brogdon has large (8-12 oz) fruit, with a thin, dark purple skin and rich, flavorful flesh. Medium sized tree to 30'. It is a hybrid of Mexican x West Indies avocados. Makes great guacamole! Ripens... Brogdon has large (8-12 oz) fruit, with a thin, dark purple skin and rich, flavorful flesh. Medium sized tree to 30'. It is a hybrid of Mexican x West Indies avocados. Makes great guacamole! Ripens from Mid July to Mid Sept. Type A/B Cold hardy, to 22F, Zones 9-11.
Size shipped 1 yr old 18-36" container grown - $29.95 Spring trees are shipped bareroot without soil or a container.

Item #: Day Avocado - Day is a hybrid Guatemalan x West Indies avocado. Green (8-16oz ) fruit. Has large buttery fleshed fruit (up to 1 lb each!). Quite cold hardy to 22F. Ripens from July-September. Type A Zones... Day is a hybrid Guatemalan x West Indies avocado. Green (8-16oz ) fruit. Has large buttery fleshed fruit (up to 1 lb each!). Quite cold hardy to 22F. Ripens from July-September. Type A Zones 9-11. Size shipped 1 yr old 18-36" container grown - $29.95 Spring trees are shipped bareroot without soil or a container.

Item #: Joey Avocado - Joey has small, egg-shaped fruit, with a dark purple skin and flavorful nutty flesh. Ripens from August to October. Extremely cold hardy, to 15-18F. Zones 8b-11. Size shipped 1 yr old 18-36"... Joey has small, egg-shaped fruit, with a dark purple skin and flavorful nutty flesh. Ripens from August to October. Extremely cold hardy, to 15-18F. Zones 8b-11. Size shipped 1 yr old 18-36" container grown - $29.95 Spring trees are shipped bareroot without soil or a container.

Item #: Pancho Avocado - Pancho has medium to large green w/red blush fruit. 6-8 oz fruit. Rich nutty flavor. Ripens from mid July- mid September. Another extremely cold hardy variety from Texas, to 15-18F, Zones 8b-11.... Pancho has medium to large green w/red blush fruit. 6-8 oz fruit. Rich nutty flavor. Ripens from mid July- mid September. Another extremely cold hardy variety from Texas, to 15-18F, Zones 8b-11. Type B Size shipped 1 yr old 18-36" container grown - $29.95 Spring trees are shipped bareroot without soil or a container.
http://www.chestnuthilltreefarm.com/store/p/176-Day-Avocado.aspx