How to Grow Avocados
Avocados are rich in protein, carbohydrates, vitamins and minerals while the
oil content consists of polyunsaturated fatty acids.
The optimum temperature for growth is 25 to 28 °C. The humidity should
preferably be above 60 %. The Mexican races originated in the cool, subtropical
highland forests of Mexico and mature trees can withstand temperatures of –4 to
A healthy avocado tree has a root system that can penetrate the soil to a
depth of 1 m. Root rot (Phytophthora cinnamomi) can develop fairly quickly in
poorly-drained soils. It is therefore essential to determine in advance the
suitability of the soil for avocado production.
Avocado growers should produce high yields of good-quality fruit, acceptable
to the consumer. There is, however, no single cultivar that can fulfil all the
requirements of the grower, the packer, the retailer and the consumer at the
CHARACTERISTICS : "Pear" shaped sometimes has a long thinner neck
SKIN : Smooth thin skin that stays green coloured when ripe. Flesh bruises easily.
FRUIT SIZE : Medium sized.
SEED : Medium sized
SEASON : Mid to late February from the Limpopo Province until (early) August from Kwazulu-Natal. 'Out of season' fruit is available year round
STORAGE : Ripens quickly out of cold storage - approximately 7 days from picking. Store at +5 degrees C - NOT COLDER - when green. Fruit will develop big brown and black cold damage marks if stored at colder temperatures
TASTE : Best known variety.
CHARACTERISTICS : Round / egg shaped fruit
SKIN : Thick, green, pebbly skin changes colour to purple/black when ripe/ready to eat. Skin does not yield to pressure easily - once soft or shriveled, fruit is overripe.
FRUIT SIZE : Small to medium (140 - 350g) - large fruit an exception.
SEED : In proportion to fruit size - small fruit, small seed.
SEASON : Mid / late May from the Limpopo Province until October from Kwazulu-Natal. 'Out of Season' fruit is available year round.
STORAGE : Excellent shelf life with very few port harvest problems. Store at +5 degrees C - NOT COLDER.
TASTE : Rich and nutty, as opposed to the stringy/watery "Natal" seedling varieties
CHARACTERISTICS : This variety has a definite "neck" compared to the other varieties.
SKIN : Thick rough green coloured skin that stays green coloured when ripe. The thick skin does not yield to pressure easily.
FRUIT SIZE : Medium to large (230- 550g)
SEED : Medium to small
SEASON : Short season. June from the Limpopo Province, July from Kwazulu-Natal. Out of season fruit not easily available
STORAGE : Store at +7 degrees C - NOT COLDER
TASTE : Sometimes slightly sweet.
CHARACTERISTICS : Late season egg shaped fruit
SKIN : Slightly rough dark green skin that stays green coloured when ripe
FRUIT SIZE :Large (300 - 500g)
SEED : Large
SEASON : August / September from the Limpopo Province. October from Kwazulu-Natal. Late season fruit readily available
STORAGE : Store at +5 degrees C - NOT COLDER
TASTE : Good.
Layout of orchard
An avocado orchard should be profitable within 7 to 10 years.
There are 3 patterns according to which trees can be arranged in an orchard:
• Rectangular (which leads to hedge-type tree rows)
• Square (which leads to a change of direction when thinning diagonally)
• Diamond-shaped (which also results in a change of direction of tree rows
Planting distance and planting pattern
The choice of a planting pattern (rectangular pattern discussed here) depends
on the management practices followed.
- Early yields are maximised by planting trees close together in the row.
- Hedge-type tree rows are more suitable for installing a permanent
- Where implements are constantly used in orchards, the hedge-type layout
is more suitable because access to the orchard is possible for a longer
period of time than it is in a square layout. Traffic is also always moving
in the same direction in such an orchard—an important point in orchards
planted on a slope.
- The hedge-type tree-row layout minimises the effects of the loss of
branches and trees in a row.
Leaf analysis indicates the nutrient status of an orchard. The trees can be
fertilised accordingly. Soil analysis, in addition to leaf analysis, increases
the reliability of the recommendations made.
- Do not fertilise young, transplanted avocado trees too soon, preferably
only after one year. The trees must first become well established and grow
- Never apply fertiliser against the stems of young trees. It must be
spread evenly about 0,2 m from the stem to approximately 0,5 m outside the
drip area of the tree.
- Each fertiliser application must be followed by a light, controlled
- Fertilisers must not be worked into the soil.
Avocado producers must be familiar with the insects that occur in orchards as
pests. Most of these are controlled by natural enemies. The injudicious use of
agrochemicals on avocado trees could, however, allow minor pests to develop into
major economic risks.
This pest has only recently gained economic importance in avocados. When
the fruit is picked before it is ripe, the larvaenever reach maturity.
However, if the fruit remains on the tree for extended periods, as in the
home garden, fruitflies may occasionally develop to maturity.
Phytophthora root rot
Root rot, caused by Phytophthora cinnamomi occurs worldwide. Locally it
is one of the most important avocado diseases and is found in all production
areas, as well as home gardens. The severity of infection varies, but the
potential loss is very big if no control measures are taken.
This is another form of Phytophthora infection, but it may be caused by
P. citricola, P. cactorum and P. cinnamomi.
This is a pre as well as a post-harvest problem and can cause serious
losses. It is present in most, if not all, production areas of the world.
This is a fruit-spotting disease, caused by the fungus Pseudocercospora
- While the fruit is on the tree, it remains hard.
- It becomes soft and edible only after picking.
- A mature fruit ripens evenly. The edible part acquires a smooth,
buttery texture and the peel shows no sign of shrivelling.
- Immature fruit, that is fruit picked too early, will not ripen
properly and the skin will eventually become shrivelled.
The maturity of the fruit is closely related to moisture content. The
fruit is normally ready to be picked when it has a moisture content of about
80 % or less. The following procedure may be applied to determine maturity:
- To test if the fruit is ready, pick a few of the big ones and leave
them. If they start to feel soft after 8 to 10 days without shrivelling,
you can pick the other big ones. If they shrivel, they are not ripe yet.
Always handle fruit carefully during harvesting and packing because avocados
are bruised and scratched easily.
- Fruit should be taken one by one from the picking bag, by hand, and
placed in the trays.
- Take special care when transporting fruit to the pack house.
- Trays containing fruit and awaiting transport should be kept in the
shade under the trees. If there is not enough shade, the fruit should be
covered with empty trays, placed upside down.
- Do not spread a tarpaulin over the trays, because it will hamper
ventilation and cause the temperature underneath it to rise.
- Harvested fruit should be removed from the orchard as soon as
- It is important to pack and dispatch the fruit to the market, or to
place it in cold storage, on the day it is harvested.
To delay ripening, fruit must be stored at a low temperature as soon as
possible. The lower the temperature, the longer the fruit will take to
ripen. However, storage temperatures that are too low will cause cold damage
of fruit. A temperature of 5,5 °C is generally best. Early maturing avocados
may be kept at a slightly higher temperature while late-season fruit may be
kept at a slightly lower temperature.