One of the
highlights of early summer is the sweet juicy taste of a fresh
picked strawberry. Hydroponic strawberries are making a big
impression! Grown without soil in a nutrient solution,
hydroponic strawberries are the taste of the future.
Canada consumes far more
strawberries than its annual production of approximately 30
million tonnes. The bulk of imports come from California and
Florida which provide Canadians with fresh berries year round.
Strawberry growers worldwide
fumigate the soil with methyl bromide before planting to control
soil-borne insect pests, diseases and weeds. The fumigation is
essential to meet the demands for top quality fruit and high
yields. However, methyl bromide has proven detrimental to our
ozone and in 2005 faces a worldwide ban. It is estimated that
banning methyl bromide will cut in half the annual production of
field-grown strawberries in California and Florida. For the
consumer this will mean an increase in the already astronomical
prices for fresh berries out-of-season. Growing strawberries
hydroponically eliminates the need for methyl bromide. Many
commercial growers have all ready switched to this method of
cultivation.
Hydroponics is rapidly becoming
recognized as the most productive and efficient form of food
production. Whether produce is grown indoors under artificial
light or outdoors in sunlight hydroponic cultivation offers
strawberry growers many advantages.
One of the major benefits of
growing strawberries hydroponically, aside from the magnificent
taste, is that they can be grown at an elevated height. This has
proven to be a great benefit to commercial growers as the
picking rate is much faster and less fatiguing and cultivation
of plants is easier.
Yields per plant are higher and
losses are lower in hydroponics than in soil. Crops can be grown
on poor land and weeds in the crop are virtually eliminated.
Gardens can be vertically tiered to maximize the use of space.
The sky’s the limit on how high you want to stack your gardens.
Strawberries are members of the
Rose family (Rosaceae, genus Fragaria) which also includes other
fragrant and flavourful species such as apples, pears, plums and
cherries. Originally the succulent berries were called
strew-berries for the way the runners and berries grew strewn
across the ground. However, as so often happens with the English
language, the name gradually evolved to strawberries.
Strawberries are not really
berries or fruit in the “botanical” sense (i.e., the end result
of a fertilized plant ovum). A strawberry is actually an
“aggregate fruit” — the “real” fruit are the objects we think of
as the “strawberry seed” (properly called “achenes”) which are
fruits in the same way that a raw sunflower seed with it’s tough
shell is a fruit. The “berry” is actually an “enlarged
receptacle” and is not reproductive material. As a result,
strawberries must be picked at full ripeness, as they cannot
ripen once picked.
Rich in vitamin C, iron,
potassium and fiber strawberries have also been credited as
having cancer fighting compounds. For hundreds of years
homeopathic practitioners have incorporated strawberry plants
and fruit in the treatment of anemia, diabetes, rheumatic gout,
and kidney and liver complaints. Fresh strawberry removes tarter
and teeth stains, soothes sunburn and lightens freckles.
Strawberry liqueurs, preserves and jellies are widely used
worldwide. The average American consumes more than 1.4 kg. (3
lb.) of strawberries per year.
Growing strawberries
hydroponically at home can produce enough berries to feed a
family of four for a full year. Production doesn’t need to stop
seasonally as a hydroponic system can be set up outdoors or
indoors with artificial light.
A hydroponic system can be
tailored to suit almost any growing application; strawberries
are well suited for hydroponic cultivation. Perfect water and
nutrient levels can be easily maintained to produce plump,
juicy, unblemished fruit.
There are different categories
of strawberries. The ones most commonly found in our hemisphere
are the long-day-type. They flower in response to the long
daylight hours of June, fruit in July then flower again, usually
yielding little or no fruit from the second flowering.
Temperature has a major
influence on strawberry physiology and can override day length
as the control mechanism for flowering. If temperatures drop too
low, vegetative growth is inhibited causing poor flower and
fruit formation. Conversely if temperatures are too high
strawberry plants will wilt and stop producing flowers and
fruit.
Strawberries grown from seed
will usually take two to three years to mature, not the ideal
situation for hydroponic growers. Early in the season, after
risk of frost is over, purchase cold-stored runners from your
local nursery. Always use runners that are certified virus
tested. Cold stored runners are off-shoots of a mature
strawberry plant (also known as a mother plant) that have been
snipped off and rooted, forming a clone of the original
strawberry plant. They are kept in cold storage through the
winter. Ideally the runners you choose will be in flower or have
buds visible.
Determine which hydroponic
gardening method will be suitable for your location and number
of plants. Ebb and flow or flood and drain works well for a
large number of plants, however, it is totally immobile once set
up. Smaller, multi-tiered deep water culture, NFT (Nutrient Film
Technique) or drip irrigation gardens seem to be the preferred
choice for both hobby and commercial growers.
Carefully remove the runners or
new strawberry plant from its container. Remove as much of the
earth as you can by gently shaking and massaging the roots.
Submerge the entire root system in a bucket of cold water for
about 10 minutes then rinse roots under cold running water to
remove any remaining dirt. Be very careful to inflict as little
damage as possible to the roots and tiny root hairs as too much
breakage will seriously stress plants and impair growth. Dry or
brittle leaves and roots should be removed at this time.
It is important to keep the
roots moist while planting. Exposure to the sun or wind will
quickly dry out the tender rootlets. This drying will cause
failures in the establishment of the planting. A convenient way
to keep the roots moist is to wrap them in wet burlap and then
carry them in a pail or basket.
Line the bottom of a hydroponic
mesh pot with a sterile growing media. Leca, expanded clay
pellets or heydite, or crushed shale rock work very well for
strawberries. There are many other media available, discuss
which one works best for the type of hydroponic garden you’ll be
using with your hydroponic merchant.
Presoak all media in pH balanced
water for at least a half hour prior to using. Dry media will
act like a sponge and suck all moisture from plants roots.
Carefully place one strawberry
plant in the pot with roots splayed over the media. Add enough
of the growing medium to fill the pot making sure the crown of
the strawberry is well above the surface. The crown requires
light and fresh air as this is where new leaves and flowers
grow. If submerged, the crown will rot causing the entire plant
to die.
Insert the pot into your
hydroponic garden and follow the instructions. Make sure plants
receive a good water-to-air ratio and that roots are never left
standing in still water or solution. A feeding regime with a
standard two part bloom nutrient formula should provide all the
nourishment that your strawberry plants will require to grow
robust and flavourful berries. pH should be maintained between
5.8 and 6.2 to ensure maximum nutrient uptake.
There are several different
types of strawberries suitable to various climates and zones.
The long-day-type typically grown in northern regions are light
and climate sensitive. Flower and fruit production is triggered
by the long hours of spring and early summer light received by
the plant. Once introduced to a warm climate, plants will
continuously produce an abundance of flowers. Temperature also
affects a fruit’s flavour and sugar content.
Conditions can easily be
simulated indoors, out-of-season. Once plants have finished
fruiting and produced runners, clip the runners from the mother
plant and root using conventional rooting methods. Treat mother
plants as annuals as they will not winter well in a hydroponic
garden.
Once cuttings or runners have
established a good root system, they must endure a chilling
process. This may be done by placing rooted cuttings in a garage
or cold cellar where temperatures remain between zero and 5°C.
Chilling may last anywhere from 10 days to five months depending
on when your next crop is desired.
Introducing
the chilled cuttings to a growing environment at staggered times
will yield a delicious supply of fresh berries year round.