“Technology Transfer of
Greenhouse Aeroponic Lettuce
Production Information to Alberta
Growers”,
Nabeel Mohammed
Greenhouse Research & Production
Complex ( GRPC)
Lacombe - AB
January 18, 2017
Introduction:
• Alberta’s greenhouse industry (137 hectares) is ranked fourth in the country
after Ontario(1,330 ha), BC (531 ha), and Quebec (262 ha).
• Lettuce is one of the most commonly grown greenhouse vegetables in Alberta
after cucumbers, tomatoes, peppers with an area of 6,842 m2.
• According to Statistics Canada, Canadian production of lettuce in 2014 was
19.9 ha. Domestic consumption was 9.14 kg/ person. Import of 283,770 tonnes
were required to meet this demand and there were no exports.
• Quebec (72%-14.37 ha) and British Columbia (10%- 2.07 ha) are the main
production areas of lettuce in Canada.
• Alberta consumed 21,357 tonnes of lettuce in 2011 (20-30%) of Canadian
production, yet only 5% are produced here (0.46 ha).
• There is an opportunity for Alberta greenhouse producers to increase lettuce
production and replace imports.
Project Purpose:
To compare the performance of aeroponic production system
designed (A shape) to optimize the yield, maturity and quality
with the hydroponic floating raft technology using the same
nutrient solutions at each growing stage according to their
potentials and limitations for lettuce production.
To provide producers with information to make business
decisions related to greenhouse lettuce production.
What is Aeroponics:
What is Hydroponics:
Aeroponics: Hydroponics:
• Aeroponics: is a system which
the roots are suspended in the
air and saturated with a fine mist Hydroponics: is the method
nutrient solution at designated growing of plants using water
time intervals to minimize water and the essential nutrients
consumption. required without the presence of
soil.
The Potential of the
Aeroponics
Technique:
Aeroponics is a research tool for nutrient uptake, monitoring of plant
health and optimization of crops grown in closed environment.
Root Oxygenation (Role of Oxygen O2):
The plants are totally suspended in the air and access to 100% of
the available oxygen in the air.
Promoting root metabolism and plant growth.
The plants in an aeroponics environment grow faster and absorb
more nutrients.
Lack of O2 can cause root- cell death-increase the risk of root
disease such as Pythium.
Nutrient solution carry dissolved oxygen greater than 7 ppm (DO-
amount of oxygen O2 dissolved in water).
(Role of Oxygen O2):
Fine droplets 20-100 microns produce excessive
root hairs.
Large droplets over 100 microns lead to less
oxygen.
Misting time:1-2 minutes at different interval times
up to 5 minutes.
Root formation, number of roots, root length
increased as dissolved oxygen( increased.
Root zone temperature:
(Cool nutrient solution hold more DO for root uptake).
Plants grow longer and faster.
Accelerates biomass growth and reduces rooting
time.
(Role of Oxygen O2):
Before
After
Before
After
Systems Component :
How Does Aeroponics Work?
Flow Confirm.
Water Tank 250 L.
Automated Batch Tank High Level.
Argus Batch Tank Low level.
Control
System.
Recirculation
System.
Stock
Tanks.
Dan Foggers 4 & 2 Ways.
PVC Pipe ¾”.
Dan Plug.
Low pressure water
pump (1 HP).
Advantages of an
Aeroponics System.
Decreased water use of 80-90% less hydroponics.
Re-use of the nutrient solution.
Space - plants stack vertically, roof topping greenhouses.
Weight.
Increase water uptake.
Excellent aeration.
Disadvantages of an
Aeroponics System.
• Clogged foggers, Pump failure or breakdowns (pipe)
going unnoticed may damage plants in a short time.
Limitations:
Knowledge &Time
Growing Conditions
&
Nutrient Solution:
Nutrient Solution:
• pH= 5.8
• Electrical Conductivity (EC)= 1.9-2.2 (winter).
1.6-1.8 (summer)
Nutrient Solution (Target ppm): Ca 180-200 , P: 50, K:210, NO3:165, Fe: 3-5,
Mn:0.5, Zn:0.1, B: 0.5, Mo:0.05.
Temperature:
Day = 16-18 °C Night= 10-12 °C
Depends on the Growth Stage.
Different Growing
Mediums & Cultivars:
Growing Mediums:
Rockwool, Peatfoam &
BVB Sublime Plug
Cultivars :
Butterhaead, Red & Green Leaf &
Oak Leaf.
Marketable Size:175 g and over.
Cultivars
Butterhead Lettuce
Alexandria (RIJK ZWAAN ):
It has good size and performance. Summer cultivar (long day).
Frank (BUYER):
A great shaped lettuce with a well filled head and a good balance of outer leaves.
Oak Leaf Lettuce
Pagero (ENZA ZADEN):
Has a highly attractive, nice fresh green color. This big sized cultivar has very regular heads.
Romaine Lettuce
Intred (BUYER):
Unique internal red color. Very nice heart shape, medium size, good shelf life.
Thumper (BUYER):
Compact little lettuce with a good uniform head shape. It is very stable.
Trial
Cultivar: Frank (Butterhead).
Seeding date: June 27,2016.
Planting Out: July 12,2016.
Harvesting day : August 8,2016
Old Trial
Butterhead
Lettuce,
V. Alexandria
Marketable Size:175 g and over.
Alexandria
Aeroponics Hydroponics
325 g 255 g
Seeding date Oct 5,2016 Planting out: Oct 20,2016 Picture day Nov 22,2016
Marketable Size:175 g and over.
190 g Thinker 220 g
Hydroponics Aeroponics
Seeding date Oct 5,2016 Planting out: Oct 20,2016 Picture day Nov 14,2016
Marketable Size:175 g and over.
Frank
Hydroponics Aeroponics
215 g 235 g
Seeding date Oct 5,2016
Planting out: Oct 20,2016
Picture day Nov 14,2016
Intred
Aeroponics
Hydroponics
145 g
110 g
Picture day Nov 14,2016
Planting out: Oct 20,2016
Seeding date Oct 5,2016
Marketable Size:175 g and over.
Yield(Kg/m2):
14
A
12
10
8 Aeroponic A
B
6 Hydroponic B
Productivity:
Depending upon the cultivar, time of the year and supplemental winter lighting.
Physiological Disorder:
Tip burn happened in both systems & cultivars
under supplemental winter lighting.
Tip burn
The physiological disorder tip burn remains a constant threat for growers.
Tip burn of young, inner leaves of lettuce is caused by a calcium deficiency,
environmental factors that reduce the transpiration rate such as:
High relative humidity (RH).
Sudden temperature changes.
Low light or low temperature.
In the older and outer leaves can develop as a result of insufficient water, high
salts or excessive transpiration due to low RH.
Symptoms : browning of the edges and tips of the leaves.
Preventions:
Increasing ventilation and air movement around the plants.
Altering the nitrogen and potassium balance to increase calcium uptake.
Calcium levels in the nutrient solution must be high enough during the growing
season.
Use low temperature and low light with the formation of lettuce head.
Cost Effectiveness and Productivity.
• The initial cost of building an Aeroponics system is higher
than the initial cost required to build a Hydroponics system.
• Aeroponics – Butterhead Lettuce produces 360 heads/cycle
12 cycles per year this will produce 4320 heads per year.
• Hydroponics for the same conditions will provide you with
1980 heads per year.
Timing.
Average weight from planting out until harvest /
Aeroponics
45
40
35
30
25
Days
20
15
10
0
Leaf Lettuce Green Butterhead Red Butterhead
Cultivars
Aeroponic vs.
Hydroponic
Aeoponic (A Shape) Hydroponic
Nutrient Solution Nutrients in mist of water Nutrients in H20 solution
droplets
Water Use Low recirculating mist of High recirculating flow of
Efficiency droplets water
Yield 360 lettuce heads in 9 Square 180 lettuce heads in 9
Meter square Meter
Risk Factor High Medium
Conclusion:
Major attraction of aeroponics is the ability to watch the root system grow and
develop.
Regular maintenance schedule, filter needs to be kept clean.
No blocked foggers- kept clear and function correctly.
No commercial greenhouse aeroponics lettuce production in Alberta.
Suppliers:
• Southern drip Irrigation: Lethbridge.
Pumps, Fittings, Foggers, Pipe—etc.
• Seeds: Canada.
RIJK ZWAAN, ENZA ZADEN, BUYER &
VITALIS.
• Growing Mediums:
Grodan – Red Cliff.
Peatfoam-Mexico & Calgary-CPS.
BVB plugs- Ontario.
• Lettuce Raft 18:
Beaver Plastics-Edmonton.
Future Considerations:
Aeroponic System?
• Development & Adaptation- Commercial Greenhouses, Rooftop &
Vertical Farming ?
• Automated Harvesting System?
Thank
℃
you
