Strawberry
cultivation
By Dr. Ali Muhammad Khushk and Aslam Memon
Pakistan is producing a limited quantity of strawberries
which are either eaten or used in preparing ice-cream, jam,
jelly, pickle, cake or milk shake. The fruit fetches Rs100 to
Rs120 per kg in big cities.
The
wholesale price of the fruit comes down to Rs 50 per kg during
the second fortnight of March when the crop production touches
its peak. The per acre income from strawberry crop is
estimated to Rs100,000 per season.
There are a number of reasons for restricted production, like
the climate, size and taste. By overcoming problems related to
quality, quantity and perishability of the fruit, Pakistan can
also export it to Europe, the United States and Middle Eastern
countries. Its saplings can be obtained from nurseries located
in Mingora and Madayen (NWFP) at a rate of ReI per unit.
There is no one variety of strawberry which possesses all the
desirable characteristics. Some are superior to others only
because of certain characteristics. In general, the
differences in tastes between different varieties are not
given as much weight as in case of some other fruits. Some of
its superior varieties enjoy colour that is very attractive.
Its varieties grown in Pakistan are Chandelier, Corona and
Stuff. These are mostly sour and small in size.
Planting:
Ordinarily, strawberries are propagated from runner plants
grown by large commercial growers. The sale of runner plants
is frequently a sideline business which supplements
the
main income from the fruit. The best strawberry transplants
are less than a year old.
A good transplant should have an extensive fibrous root
system, seven or eight inches in length. This type of root
system usually develops best in rather loose sandy soil. Such
soil also facilitates digging the plants and cleaning the
roots for packaging.
Timings:
Early spring is an ideal time for planting as it ensures good
development for increased productivity the following season.
Fall planting is not recommended due to greater problems with
weed control and the cost of winter mulch. The number of
plants needed per acre depends upon the spacing system used.
Method:
The
main planting system used for strawberry cultivars is the
matted row. Set the plants 11/2 to 21/2 feet apart in rows
spaced 3 to 4 feet apart. Let the runners develop until the
row is I to 11/2 feet wide.
This system allows for easier weed control, easier harvest,
less fruit rot, and fewer foliage diseases than other systems.
The raised bed provides higher spring soil temperatures and
better drainage, allowing faster establishment and earlier
cropping.
Inter-cropping:
Fruit growers often find it economically beneficial to grow
strawberries between the rows of young fruit trees until they
become of bearing age. Such intercropping is well justified so
long as the strawberries do not interfere with the culture of
the tree fruits, which represent a much greater investment.
Usually it is not wise to plant strawberries closer than six
to eight feet to tree fruits. Otherwise they are likely to
interfere with cultural operations for the trees and may
compete for water and nutrient materials in the soil. Often
the trees suffer more than the strawberries.
Mulching:
Mulching is necessary in June bearing varieties to protect
flower buds from temperatures below 15' F and to protect
crowns from heaving damage. A three- to five-inch layer of
straw mulch be applied after a few hard frosts, usually in
late October or early November.
Frost protection:
Keep in mind, however, that strawberry growers tend to over
emphasize the importance of fertilizers and underestimate the
importance of water. Yields are more frequently reduced from
lack of water, poor soil drainage, and poor soil physical
properties than from a lack of fertilizer.
Irrigation:
Sprinkler irrigation is crucial to prevent frost damage in
June bearing varieties after the mulch is removed in early
spring. Irrigate whenever the air temperature drops below 34'
F. Apply 0. 1 inch of water per hour
with
one sprinkler head revolution per minute.
Sprinkler irrigation should protect flowers and developing
fruit down to 20' F. Spring frost protection is unnecessary
during the planting year in day-neutral strawberries because
the flowers are usually removed until the danger of frost is
past. Frost protection may, however, be desired in the fall to
extend the harvest season.
Day-neutral strawberries require more careful irrigation and
water management than June-bearing strawberries, especially on
raised beds. During the summer apply 0.75 to 1.5 inches of
water per week depending on the weather, soil type, and
effectiveness of mulch in preventing evaporation.
Use trickle irrigation with plastic mulch to ensure sufficient
water in the root zone. Overhead irrigation may be used with
straw or other organic mulches. Fertilizer can be applied
through the irrigation system. Higher levels of certain
nutrients such as nitrogen may be needed if trickle irrigation
is used because of increased leaching through the soil
profile.
Fertilizers:
Nitrogen, phosphorus, potassium, and other soil nutrients are
required for vigorous crown and runner development. Soil tests
will identify the nutrient needs. Generally phosphorus,
potassium, and part of the nitrogen should be applied at or
before planting. On most soils and under most conditions
strawberry plants will be benefited by the application of
commercial fertilizers, particularly by nitrogen, during the
first growing season.
Weed control:
A weed eradication programme one year prior to planting is
recommended if perennial weeds are a problem. Herbicides,
mechanical control methods, and a green manure smother crop
can be used effectively. Consult herbicide labels to avoid
potential carry-over problems for the new strawberry planting.
Preplan harrowing of a prepared field will reduce weed
populations.
Insect control:
Not all insects found in a strawberry patch injure the plants
and many of those that do can be controlled by preventive
measures more easily than by chemicals. Rotation of
strawberries with other cultivated crops is useful in
controlling insects.
Strawberries are affected by several diseases that vary widely
in their occurrence and severity; it is necessary to recognize
common strawberry insect and disease problems in order to
treat them quickly and effectively. Prevention is the best way
to hold disease and insect problems in check. The use of good
cultural practices, varieties adapted to the area, and
disease-free stock will help reduce insect and disease
problems.
Harvesting/marketing:
Proper
picking, grading, and packing are as essential as good
cultural practices to success. The harvest frequency and
duration depend on weather conditions, varieties, soil
factors, and cultural practices. Strawberries are almost
entirely hand picked. As a general rule for wholesale
operations, six to nine pickers are needed for one acre.
Source: The DAWN
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