Growing Avocados in
(949) 830-5653
www.lagunahillsnursery.com
Avocado is one of the most valuable produce sold and
fortunately can be grown nearly anywhere in
Commercially the best locations are between 700 and
1500 feet altitude on a hill with south or west exposure with excellent cold
air drainage and soil drainage.
Locations that match these criteria will suffer from the fewest crop failures.
Avocados trees are bushy evergreen trees with large
leaves that can potentially grow 30+ feet tall and nearly as wide, but are
usually maintained lower. Modern
orchards are kept below 20 feet tall.
The trees create ample shade and the ground beneath them is usually
covered (and should be covered) with their dead leaves. Most produce small creamy green flowers in
spring and the resulting fruit ripens 6-18 months later. Although not essential, most local orchards
plant 2 varieties for cross-pollination, which can increase crop volume
slightly.
There are 2 main races of Avocados, Mexican and Guatemalan. Mexican avocados are a bit hardier to cold
and the fruit is typically smaller with thin black skin and a stronger
flavor. Guatemalan avocados are larger
with thicker skin and more sensitive to frost.
Many of the most recently introduced varieties are hybrids.
Start with a Good Plant
Avocado trees grown for retail sales generally
die or perform poorly. Trees grown in
retail friendly 5-gallon, 15-gallon, and 24-inch box are always grown in a soil
that contains significant amounts of sawdust or finely ground bark. Although they may be healthy initially, the
decomposing sawdust or bark eventually causes root problems. As the organic
matter decomposes the permeability of this soil and the available oxygen for
the roots decreases. If the soil where
the tree is planted is extremely permeable (sandy), performance may be
satisfactory. If great care is taken,
the soil of a retail tree can be removed by washing with water and the “bare
root” tree can then be planted into the garden soil with improved
performance.
A
far better result occurs if trees are acquired from a commercial orchard
supplier. These trees are grown in
bottomless plastic tubes filled with decomposed granite. Orchard trees are also available grafted to clonal
rootstock with genetic resistant to root rot diseases. (Interestingly, clonal rootstock is usually
grown in a soil mixed with wood chips.)
Avocados
are easy to grow from seeds (pits).
Avocados seeds are zygotic so seedling trees are normally similar to the
fruit it came from, but not genetically identical. (As similar as children are to their
parents.) Seedling trees normally grow
about 10 feet tall before flowering and fruiting, which may take 3-5
years. There seems to be better than a
50% chance that the fruit will be good to eat.
The World famous Hass variety was a seedling that refused to
accept a graft that grew at the Hass orchard in
Avocados will grow in sun or shade, however sun is required for maximum
production. The most important factor is
having soil with excellent drainage.
Excellent drainage can be determined by digging a hole about a 18 inches wide and deep
and filling it with water twice. If the
water from the second filling disappears within 24 hours the drainage is
adequate. Faster is better. Some advisors recommend 15 minutes to drain
on the first fill! Clay soils can drain
adequately if located at or near the top of a slope.
On poorly draining soil you can create a raised bed (minimum 18”), a
French Drain, a dry well, or plant Citrus instead.
One of the most recent recommendations is to dig a hole 1 foot deep and
8 feet across. Mix enough sand and/or
pumice with the dirt so that you end up with a caldera-like mound that is 18-24
inches higher than the original soil surface.
This mound is of adequate size and drainage to grow 1 or 2 trees.
Installing the Plant
Dig
a hole about 18 inches deep and wide.
Place the cylindrical sleeve containing the roots and soil vertically at
the center of the hole so that the surface of the root ball matches the surface
of the surrounding soil. Slit the
plastic sleeve that covers the root ball and peel it off. Do not lift the root ball after removing the
plastic sleeve. Mix the soil that you
removed from the hole with an equal part of
Newly
planted trees are normally staked and white washed. The surface of the soil should be mulched
deeply at all times, preferably with old Avocado leaves that drop off the
tree.
In Containers
Choose
a big pot. Deeper pots provide better
drainage. Sand is an ideal potting soil
for containers taller than 18 inches.
Sand mixed with either peat moss, perlite, or pumice will help lighten
the soil. It is important to keep potted
trees moist at all times. This may
require daily irrigation or even twice daily irrigation during the warmest
weather.
Seedling Avocado trees grow with perfect symmetry
and the leaves adequately shade the tender green branches below. Grafted trees, compared to seed grown trees,
have asymmetrical growth habit that allows full sunlight to strike the
stems. While leaves tolerate extreme
heat, green stems can burn with exposure to sun at temperatures are much above
90°F.
Burnt stems turn yellow, brown or black.
Severe burns can kill the branch beyond the burn area. Mild burns cause poor sap flow.
The best way to prevent sunburn is to paint any
exposed stem with a whitewash. Mix a
light colored latex paint with an equal part of water. This may need to be applied for several years
until the trees canopy is quite full.
Whitewashing may be required at any time a mature tree is pruned or when
weather (frost) conditions cause excessive leaf drop.
Avocado trees require average to
ample water. Most orchards are irrigated
daily during warm weather with micro sprinklers. The soil moisture should be maintained at 12-18
inches of depth and at least half of the soil under the canopy should be
irrigated.
In coastal valleys of
Avocados do not require pruning to
produce a good crop. The trees are
generally skirted (cutting off branches that are too close to the ground). They are also topped when they get too tall
to harvest. When old trees are cut down
to 4 feet production resumes in 2-3 years.
Some growers maintain trees at 12 feet tall with constant pruning.
It has been determined that the
ideal shape for production and harvest is a dome less than 15 feet tall. Ideally all the foliage is exposed to
sunlight.
Avocado trees are essentially
self-fertile (do not require the presence of a genetically different tree),
however the crop can be enhanced.
According to the
Avocado trees bloom in 2 patterns
(Type A & Type B). Type A varieties
are female in the morning and male in the afternoon. Type B varieties are reversed. Usually there is some overlap during mid
day. A type A tree can acquire more
pollen if it is blooming close to a type B tree, and vice-versa. The trees should be within 25 feet of each
other. Closer is better.
Different varieties also bloom at
different periods of the year. Varieties
that bloom early typically flower from December to February. Mid season is from March to May and late
season is from April to June. A few
varieties bloom at other times and many old specimens bloom several times per
year.
Avocados do not ripen on the
tree. In Nature they drop and ripen on
the ground. The fruit is picked hard and
green during that variety’s harvest season.
Generally any decent size fruit will ripen, but if picked too early will
have no flavor and sometimes a lot of strings in the flesh. Most varieties have a 4-month harvest
period.
It is recommended that fruit be cut
from the tree with a tiny bit of stem attached to the fruit.
Here
is a list of the popular cultivars.
Bacon (Mexican)
10-18 oz., oval fruit with smooth, green, thin skin and pale
yellow-green flesh. Good to very good
quality with medium to large seed.
Harvest November-March. Heavy
producer. Bloom type B mid-season. Upright tree.
Carmen (sport of Hass) Similar fruit to Hass but slightly
smaller. Fruit that ripens along with
Hass are pear-shaped. Fruit that ripens
at other times is oval. This new variety
can bloom any time of the year and harvest any time of the year. It is still being evaluated to determine if
distinct bloom and harvest periods exist in
Fuerte (Guatemalan
X Mexican) 9-16 oz. pear-shaped fruit
with slightly rough, green, slightly rough skin and cream flesh, green near
skin. Excellent quality with buttery flavor.
Easy to peel. Harvest
November-April. Alternate bearing tree
may not produce in some areas. Bloom
type B early to mid-season. Large
tree.
GEM (probably mostly
Guatemalan) 7-11 oz., pear-shaped fruit
with rough, thick, black skin flecked with gold. Excellent quality, better than Hass. Easy to peel.
Harvest March-September. Good
production, less alternate than Hass.
Small tree. Bloom type A. Developed from Gwen by UC researcher Gray
E. Martin.
Hass (Mostly Guatemalan) 6-14 oz, pear-shaped to oval
fruit with leathery, rough, thick black skin and cream colored flesh. Excellent quality with medium seed. Easy to peel.
Harvest April-October, some all year.
Bloom type A mid-season. THE
LEADING COMMERCIAL VARIETY.
Lamb Hass (Mostly
Guatemalan) Similar to Hass with
slightly larger 10-14 oz. fruit, slightly thinner skin. Good to excellent quality. Can develop strings in flesh some years. Harvest May-November. Bloom type A mid-season. Heavy producer. Upright tree.
Mexicola (Mexican)
4-6 oz, pear-shaped to round fruit with thin, smooth, black skin. Excellent quality with strong nutty flavor. Large seed.
Harvest August-October. Bloom
type A. Heavy producer. Small tree.
Nabal
(Guatemalan) 16-30 oz., nearly
round fruit with thick, smooth, but granular, deep green skin and yellow
flesh. Excellent quality with large
seed. Easy to peel. Harvest June-September. Bloom type B.
Heavy producer is strongly alternate bearing.
Pinkerton (Mostly Guatemalan) 9-18 oz., rounded to pear-shaped fruit with a
long neck with medium-leathery green skin.
Very small seed. Good to excellent
quality. Harvest December-April. Bloom type A early. Heavy production further south with warmer
winter temperatures or on hills with better cold air drainage to prevent damage
to flowers. Spreading tree.
Reed (Guatemalan)
17-24 oz. round fruit with slightly rough, thick green skin. Excellent to outstanding quality. Easy to peel.
Harvest May-September. Heavy
producer. Bloom type A late. Upright narrow tree.
Sir Prize (Mexican X Guatemalan) 10-20 oz. fruit is similar
to Fuerte with rough, thin black skin.
Small seed. Excellent
quality. Harvest November-February. Bloom type B.
Production similar to Hass.
Upright tree. This may be a
perfect compliment to Hass as a pollinator and with respect to harvest
period.
Stewart (Mostly
Mexican) 6-13 oz, pear-shaped fruit with
slightly rough, deep purple skin with light yellow flesh. Small seed.
Excellent quality. Peels
easily. Harvest October-December. Bloom type A.
Good producer and quite cold hardy.
Others:
Gwen (A) and Whitsell (B) are semi-dwarf
descendents of Hass that were developed to replace Hass. Both are excellent producers with excellent
quality fruit, but both have had problems with defoliation during winter. See GEM.
Holiday (A) is a semi-dwarf tree that produces excellent
fruit in the fall and winter. The large
green fruit is 18-24 oz. Unfortunately
our orchard suppliers are not currently offering it.
Wertz (Littlecado)(A) is a dwarf tree that produces a
light crop of fair to good fruit.
Zutano (B) is the most effective pollinator for Hass but
produces low quality fruit.