Growing Strawberries in
(949)
830-5653 www.lagunahillsnursery.com
Wild
strawberries are native to all northern temperate climates and
Local
commercial farms use similar methods to produce a very early crop starting in
early to mid winter. The early crop
commands the highest prices. Nearly all
use conventional chemicals. A few farm
organically, but organic methods rarely produce a crop before spring.
Strawberry
plants require good to excellent drainage and perform best in sandy loam or
loamy sand. They will perform in heavier
soils if the bed is raised high enough to create better drainage. Local farms raise the soil about 18 inches
which also make harvesting easier. Drip
irrigation lines are installed for high efficiency and to keep the foliage and
fruit dry. From this point conventional
farming techniques are quite different.
Conventional soil
preparation
To
promote an artificially early crop the rows are covered with clear
plastic. The clear cover traps the sun’s
energy and the soil stays quite warm. To
prevent weed seed from germinating and competing with the crop the soil must be
fumigated. The irrigation lines distribute
fumigation chemicals underneath the plastic and in 5 days all seeds, diseases
and bugs are killed. The plastic is then
cut between the beds and the fields will be ready to plant 2 weeks later. Without fumigation the strawberry plants
couldn’t be planted every year and the use of transparent plastic mulch would
be disastrous.
Organic soil preparation
On
organic farms, only a fraction of the land is planted with strawberries at a
time. Unrelated crops are rotated to
avoid a buildup of pest or disease problems in any one location. A crop of legumes (beans, peas, or alfalfa)
will increase the soils nitrogen and a crop of broccoli seems to discourage a
root disease (Verticillium).
Weeds are a major problem. Weed
competition can dramatically lower production.
Some organic farms weed constantly, some cover the soil with black
plastic, some apply a surface mulch. All
options are a significant expense, but higher prices for organic produce
usually offsets the cost.
Black plastic prevents about 90% of the weeds, but doesn’t warm the
soil as much as a clear plastic mulch.
Installing the Plants
All farms acquire and install bare root plants. These plants come pre-chilled. All strawberry plants need a period of winter
chill between 34°F and 55°F to initiate vigorous growth and complete
development of flower buds. Too little
chill results in poor growth and a plant too weak to produce much. Too much chill results in a plant with super
vigor, but delayed production. The
farmer must guess how long they should refrigerate the bare root plants to
balance the chill that they will naturally receive during winter following
installation.
All farms use tractors to punch a deep hole into the bed (through the
plastic mulch) at regular intervals. The
workers then place each plant with its crown at soil level and firm the soil
around the roots to hold it in place.
The bed is then watered thoroughly with sprinklers to properly settle
the plants. Once established the farms
then use the soaker tubing for irrigation.
Local Farms Replant
Annually
In order to get the early harvest, local farmers must install
prechilled plants every year. Strawberry
plants can produce for 3-4 years, but without clear plastic mulch and
prechilling, the plants won’t produce until spring.
Fertilization
Farms usually consult with soil labs to provide proper nutrition,
however, strawberry plants do fine with levels of nitrogen, phosphorus and
potassium that are fairly even. For
short term results Osmocote 14-14-14 is fine.
For long term results use organic fertilizers.
Harvesting
Berries are ready to pick about 4-5 weeks after blooming
commences. It is best to pick off the
first stalk of flower buds to allow the plant to build strength before
production begins. Workers are sent
through each field 2-3 times per week to pick ripe berries. To maximize shelf life the berries are gently
picked, not allowed to get wet, and cooled immediately.
Growing Strawberries at Home
A typical strawberry plant can
produce fruit for 3-4 years. On young
plants remove the first set of flowers so that the plant can gain size and
strength before production begins. A
single, well-developed plant can grow over 18-inches wide and 10-inches high.
Strawberry plants should be
located in sun (1/2 day is minimum) and planted in well-drained soil. Heavy soils should be elevated into
substantial mounds or raised beds to improve drainage. Plants are placed 12-18” apart.
Strawberry plants can be
purchased any time of the year in containers or as bare root. Bare root plants are more commonly planted
during mild weather late fall through spring.
Strawberry plants perform quite
well in pots. The berries are hanging
over the edge but not touching the ground.
This gives them some protection from birds, slugs, snails and
pillbugs. You can grow a single,
full-size plant in an 8-inch container.
Our Laguna Hills Nursery custom potting soils, ACID MIX
and TROPICAL POTTING SOIL are superb.
Most commercial potting soils will provide mediocre results. Perhaps the best potting soil is construction
sand. Our favorite soil in containers is
a mixture of sand with ACID MIX.
Strawberry plants require ample
moisture at all times. Plants that get
severely dry often don’t recover until the following year. Small pots placed in deep saucers filled with
water can last a week on a single irrigation.
The “moat” that is created will also guard against snails, earwigs and
pillbugs.
During summer most plants
produce baby plants on long stems called “runners”. These baby plants will grow roots where they
touch the soil. These can be removed to
increase production of berries or saved to increase the number of plants. The baby plants start production the next
year. Do not allow too many plants to
grow. Try to keep them a minimum of
6-inches apart on center. Older plants
and dead plants can be removed to make room.
Results are improved greatly if several handfuls of soil are also removed
and replaced.
Strawberry
plantings require crop rotation, just like any other crop.
The plants that grow from
runners are clones and genetically identical to the parent. Strawberry plants will also grow from seed,
however these will be genetically different.
VARIETIES
Strawberry
varieties can be classified as to when they bear fruit and how they grow.
June
Bearing (Short
day) varieties are most common.
They generally have the largest, highest quality berries and are the
most productive. They
also produce the most runners during summer.
The
Camarosa This is a popular commercial variety with high yield and large to very large firm fruit of good flavor. Mildew may be a problem.
Palomar A new commercial variety for local growers that has excellent flavor. The flesh is firm.
Sequoia
This variety set the standards for flavor and sweetness in
Ventana Similar to Camarosa with slightly larger fruit and slightly better flavor (considered very good).
Everbearing
& Day Neutral
These
varieties produce continuously, although heaviest in summer and sporadically
through fall. Mild coastal conditions
promote more constant production. High
temperatures inhibit flower production.
San Andreas Similar to
Seascape The fruit are large and attractive with glossy skin and very good flavor. This variety resists many viral diseases and is highly productive.
Alpine
(
These
small, clump-forming, plants produce small (tiny), highly fragrant berries over
a long period during warm weather. These
can be grown from seed or divisions.