Food & Farming Entrepreneurs Network
Task & Finish Workshop 2
Growing in Closed Buildings - Ultimate Intensification
Martin McPherson, STC Ltd
&
Howard Campion, H2O Farms
Growing in Closed Buildings
“Ultimate Intensification in
horticulture”
Martin McPherson MBPR (Hort.)
Science Director
Stockbridge Technology Centre Ltd
A Glasshouse Industry Transformed
The Glasshouse Industry
Much larger glasshouse units
Significantly taller structures
Improved light transmission
Increased efficiency & yields
BUT….
Reliance on solar performance & light
quality & its interception is fixed
They remain energy inefficient
Labour costs, in many cases, are high
Where is the next major step change?
Key Drivers for Change
Population
growth Food
security
Water
availability
Energy
costs
Climate
change
Regulatory
pressures
Environment
issues
Government Chief Scientist
Sir John Beddington
“A perfect storm scenario”
The ‘Foresight Challenge’ and…
….a need for sustainable intensification
“Sustainable Intensification”
….a simple and appealing concept….
– to maximise food production efficiency in terms of
external resource inputs and on the smallest necessary
land area
The term “Sustainable” implies the use of resources at a
rate that does not exceed the capacity of the planet to
replenish them
Vertical Farming is not a new concept
…but it is starting to move
into the 21st Century
Vertical Farming Systems
Various systems designed to
optimise production
The main limiting factor is
light (or lack of it)
In Northern Europe solar
radiation levels are variable
and often limiting
1% light loss is equivalent to
approx. 1% yield loss
Supplementary lighting
HDC-CGA project No. PC201 at STC
Concept to use all latest horticultural technology to see
what the ultimate crop potential was
Highly successful with >100% yield increase
But…uneconomic, primarily due to cost of conventional
lighting using high pressure sodium lamps
This was 5-6 years ago…and technology has already
moved on….
AYR Cucumber Project
Changing Lighting Technology …Is there an opportunity here?
High Intensity Discharge (HID) lights are
inflexible due to heat signature
They can‟t be placed close to the crop so
inappropriate for vertical farming systems
Innovative LED lights offer an alternative
cool & energy efficient light source
BUT…they have not yet been fully validated
in the horticultural sector
Spectral Range for Plant Growth
Plants respond differently to light of differing colour.
In general, red light stretches while blue light encourages shorter plants.
The optimum ‘light recipe’ needs to be developed for each species
Function of Spectral Quality
Light Spectrum Wavelength Band
(nm)
Comments
UV-B 280-320 Deleterious for growth
UV-C 320-400 Might have additive effect
to blue light
Blue 400-500 Necessary for elongation
control
Green 500-600 Less important in
photosynthesis than red
spectral range for certain
plants
Red 600-700 Optimisation is necessary
to avoid abnormal
development
Far red 700-750 Enhancement of flowering
& stem elongation
A cool light source – opportunity to pioneer novel vertical
cropping systems
Low voltage - Improved energy efficiency
Improved spectral control (switchable/dimmable)
Extended durability (reduction in labour costs)
Option for integration into specific lighting „recipes‟
Enhanced safety (lower voltages & operating
temperatures & reduced risk of glass injury)
Sustainable attributes (recycling, absence of mercury etc)
Unique Attributes of LED‟s
Demonstrating the Benefits of Spectral Control
HDC CP19 (2003-2007) Evaluation of Spectrally Modified Plastics
Demonstrating the Benefits of Spectral Control
Colour change observed in cabbage (summer green) grown
under Solatrol (left) and Standard (right) plastics
Demonstrating the Benefits of Spectral Control
Demonstrating the Benefits of Spectral Control
Demonstrating the Benefits of Spectral Control
Black peppermint Rosemary Sage Thyme
Standard 118% 598% 315% 130%
UV-transparent 111% 326% 315% 133%
Solatrol 81% 252% 316% 105%
Field 100% 100% 100% 100%
Luminance 93% 382% 554% 190%
UV-opaque 119% 507% 641% 229%
HDC CP19 : Impact of spectral change on oil yield in
herbs as a % of that in field-grown crops
Each value in the Table is the mean of 19 replicates, calculated using replicate fresh weight data but
a single, bulked oil analysis for each crop.
The story so far… …could LED’s provide the next
step change in horticulture to
enable economic multi-layer
production
Where are we?
High Wire Crops
Interlighting with LEDs Crop Improvement Centre – Bleiswijk, Holland
Already, a 15% yield increase is being
claimed for use of this new technology
BUT…it is not necessarily a good example of
sustainable intensification
Ultimate intensification through
multi-layer cropping
Hi-wire crops not a practical proposition
Other crops potentially are e.g. leafy salads, herbs,
plants in propagation, strawberries (& ornamentals)
Two options to consider here:-
- Glasshouse production
- Warehouse production
What are the advantages & disadvantages of each
approach?
Glasshouse Multi-layer
production Advantages
- Most growers have existing glasshouses
- Can benefit from free solar radiation
- Can use existing HID lights to supplement
Disadvantages
- Poor thermal insulation
- Insufficient light penetration
- Unpredictable scheduling due to weather
- high energy, transport & labour costs
- light wavelength restricted by glass
Warehouse multi-layer
production
Advantages
- Surplus warehouses available & quick/cheap to build
- Can be placed in towns & cities or next to
distribution hubs
- Can be highly insulated & energy efficient
- Mechanisation much easier
- Sealed enclosure so less risk of P&D problems
- Greater level of biosecurity
- Greater potential for environmental control
- Ultimate control over crop scheduling
Warehouse multi-layer
production
Disadvantages
- No free solar radiation (though solar panels on
roof will compensate to an extent)
- All lighting has to be provided artificially
- light „recipes‟ not yet known for many crops
Frands Jepsen, MD, Queen Kalanchoe, Denmark
“The results I have seen convince me that it is possible to grow
plants with LEDs as the sole source of light and I am beginning
to think I may have built my last greenhouse” Feb. 2011
Innovation towards
Sustainable Intensification
Question: Which is the right way
forward for vertical growing
systems –
- a glasshouse environment
or
- a closed shed?
What are the economics and
practical considerations?
Vitro Plus Fern Nursery Burgh-Haamstede, Zeeland, Holland
Is this the ultimate goal……
Developing a New Applied
R&D facility at STC
Conventional
crop HPS lighting
Multi-layer crop
with LED lighting
Multi-layer crop
with LED lighting
Experimental
multi-layer zone
for specialist
studies
2 x 200sq m glasshouses
(conventional glass for
comparative studies)
2 x 200sq m warehouses
(highly insulated to conserve
energy inputs)
F18 & F19 W10 &W11
F18-F19
Warehouse
facility
Proposed Facility Location
QUESTIONS?
Do LED lights provide the key to ‘urban farming’ systems?
Is multi-layer cropping feasible economically?
What is the optimum cultivation system for sustainable
production?
What about mechanisation in a vertical plane?
Is fixed wavelength lighting likely to give problems?
How easily will it be to control temperature & humidity in a
closed building?
Are there other issues & opportunities that need to be
considered?
Finally...is it a case of ‘science into practice’ or merely a
fairytale?