July 2020 - 9

* Indoor farms (without sunlight).
* Soilless substrate-based production
system with drip irrigation is the
most widely used production
system commercially. Productivity
seems to be limited in waterculture-base
production systems.
Regardless, production systems
are designed so that workers stand
instead of bending over the crops,
improving worker efficiency.
Strawberry
cultivar types
* Chandler, Camarosa, Camino,
Real, Florida Radiance,
FL-127 (Festival), Ruby June,
Sonata, Elsanta, etc.
Soilless-substrate-based production
systems using a simple raised gutter
supported by a leg structure anchored in the
ground is called a " table-top system. " They
are typically placed inside a simple structure
such as rain shelters or high tunnels. This
system is widely used in Europe and is
slowly being introduced in North America.
In temperature-controlled Dutch-style
greenhouses, use of steel hanging gutters
to those used for high-wire production
is common. A typical spacing between
gutters is 3.3 feet (center-to-center), shorter
than a standard high-wire spacing (5 feet).
Placed on top of the gutters, containers
and bags filled with soilless substrates are
irrigated with drip-irrigated systems.
Substrate, nutrient solution
Kubota said strawberry plants are
sensitive to root zone environment (physical
and chemical environment). Their roots
do not develop well when inappropriate
substrate is used or moisture content is
not managed well. Strawberry fruit yield is
therefore largely affected by substrates and
resulting rootzone conditions.
" Table-top " growing techniques are becoming more common in strawberry greenhouse
operations.
Physical characteristics interact with
container geometries. This means that
substrate optimization/selection must take
a whole-system approach. Optimizing
substrate physical, chemical and biological
properties can increase the overall yield of
strawberry by 30% in an OSU study.
When pre-mixed substrates are
used, it is important to understand that
what is an optimum substrate depends
on the climate conditions (potential
transpiration), container systems (column
height and drainage design) and source
water quality (e.g., alkalinity).
Irrigation
Irrigation (fertigation) is a key
management technique in high-quality
strawberry production.
Kubota said OSU typically uses a
Japanese nutrient formula that has
relatively low nitrogen concentration
(77-100 ppm with 90% in nitrate form).
Electrical conductivity is maintained at
1.0 dS/m and PH is adjusted between 5-6.
" Strawberry plants require good porosity
and drainage to assure good oxygen
availability in the root zone, " she said.
Environment, benchmark
conditions
Strawberry plant responses to
environmental conditions are a complex
topic, Kubota said.
Response to specific cultivars need
to be examined on site, rather than
simply applying general literaturebased
information - especially those
cultivars that are bred for and cultivated
in open fields for which there is little
information regarding responses to
individual environmental factors (and
their interactions).
Greenhouse-controlled environments
allow independent control of photoperiod,
light intensity and temperature among
other factors, and thereby potentially
control the plant growth and development
to maximize the crop productivity and
fruit quality.
When all conditions are at optimum
ranges, strawberry production is highly
correlated with light and plants seem
to produce 2-3 grams of fruit per every
addition of one mole of photosynthetic
active radiation (mol m-2).
With good light and optimum
environment, benchmark yield can be
700 grams to 1 kg (1.5 to 2.2 pounds)
of fruit per plant over 6-7 months
of off-season production (e.g., early
November to May.)
Productivity is also dependent on the
cultivar. However, highly productive
cultivars tend to have less flavorful
fruits (lower Brix or soluble solid
concentrations). VGN
* Long-day (Ever-bearing or
" day-neutral) cultivars.
* Monterey San Adreas, Albion,
Portola, Sweet Ann, etc.
GREENHOUSES
ANY CLIMATE,
ANY CROP
FOR OVER
40 YEARS
GROWSPAN HAS
BEEN HELPING
GROWERS
ENERGY-EFFICIENT DESIGNS
ENVIRONMENTAL CONTROL
EXPERT CONSULTATION
IN-HOUSE SERVICES
www.growspan.com
877.835.9996
VGN | JULY 2020 | 9
http://www.growspan.com
July 2020

Table of Contents for the Digital Edition of July 2020
