Plant balance and crop
steering
By André Kool, consultant Green Q
Index
• Plant = factory
• Roots, Irrigation, Substrate
• Fotosynthesis, LAI, CO2
• Climate
• Crop planning
How does the plant grow?
Radiation
CO2
(plant) temperature
Feeding
Water
humidity
Plant = factory
• Head = new development, future
• Leaves = factory producing assimilates
• Stem = pipeline (logistics)
• Roots entrance = mouth of the plant
• Fruits = storage of assimilates
A strong root system
Plant
 Roots
 Substrate
 Water management
Stimulate root growth to absorb optimal water and
fertilizers.
Water management
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Start time
Stop time
Shot lenght
Decrease of water content
Amount of gift and drain
EC drip and drain
pH drip and drain
Water management before
planting on hole
Nursery / next hole
• Stategy for 10 x 10 cm blocks ( 1 plant per block)
• Before flowering first truss block weight 300-350 g.
• When flowering slightly more water (350-400 g)
• 100 cc irrigations per block
• Sometimes (frost, hot pipes) night irrigations are required
• EC may raise from 2.0 up 6.0-8.0 mS/cm but no lack of water!!!!!
Planting on hole (rooting)
Planting on hole:
• When truss 1 is flowering/first flower of truss 2 starts to flower
• During rooting in slab (+/-some days) more water to maintain contact
slab-block
• Roots can take water from slab?
• Control period starts
Reduce water!!!
After rooting
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After rooting plants reacts “vegetative” (stem gets more thick)
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“Generative” steering with water (and climate: more “active”)
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Reduce gradually humidity slab (f.e. 9575%)
Measure weight and / or humidity
Guideline is 1% weight per day during 3 weeks
Low drain% 0-5%
EC slab rise up from +/- 3 to 5.0 max 6.0 mS/cm
After truss 3 and 4 are flowering, fruitload will start to limit vegetative growth
After control period back to “normal” irrigation strategy
After rooting
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Dangers of generative steering by too less water (especially at high EC)
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Dry+high EC= Magnesium deficiency symtoms (first in old leafs)
Dried flowers
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Pythium (especially when humidity changes from wet to dry and reversely)
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Weight scales can be helpful equipment!
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Keep always looking to color flowers and plant
Water management after control period
(“normal” irrigation stategy)
Start time
after 100 J – 150 J
2-3 hour after sunrise till 2 - 3 hour before
sunset decrease of water content
• Rockwool 8 - 15%
• Cocopeat 10 - 20%
Night shot when decrease of water content is too big
reducing root pressure
Shot length
Big shot  bigger break  dryer slab > generative
Small shot wetter slab > vegetative
Optimal shot length calculation:
2 - 5% of slab volume
Calculation and registration per m²
Decrease of water content
W A T E R C O NT E NT S T O NE W O O L S L A B
r e c o m m e n d e d d a ily c o u r s e
Water content
P1
s u n ris e
P2
P3
d e c r e a se
p e r c e n ta g e
i n c r e a se
p e r c e n ta g e
firs t
firs t
la s t
irrig a t io n
ru n -o ff
irrig a t io n
T im e
s t a rt
s uns et
s u n ris e
Weight scales & drain measurement
Decrease of water content slab
How is the calculation?
Big decrease  dryer > generative
Small decrease  wetter > vegetative
Drain and gift amount
Amount of gift
2 – 3.5 sum of radiation
depends of stage of the crop
Time of first drain
30% total drain
Drain per shot
Drain (adult crop in summer)
2.5 *
Joules
Start
3.5 * Joules
40-50% drain
First drain
2.5 * Joules
10-20% drain
3 hr before stop
Stop
EC Drip and drain
High EC > generative
Low EC > vegetative
Depends on evaporation, higher in winter time
Influence slab / drain EC
- Drip EC
- Decrease of water content
- Amount of drain
- Shot length
pH drip and drain
pH drip between 5.2 – 5.5
pH in slab between 5.5 – 6.2 for optimal uptake elements
• Low Phuptake of positive ions
• High pH uptake of negative ions
Steer the pH in root environment:
• Ammonium nitrate based on pH & HCO3-level
• Ureum based on pH & HCO3-level
Equipment to control
Weight scale
Humidity measurement
Extra checks
- measuring EC / pH / drip-drain amount
Substrate
Cocos in opposite of Rockwool:
- Higher decrease of water
content
- Bigger shots
- Higher drain EC
CO2 + LAI
Fotosynthese
Light suplies energy to transform CO2 + H20 into
the leave to sugars
Production tomato (kg/m2)
Total plantgrowth (biomass production)
• Leaf fotosynthesis
• Light interception
• Fraction to fruits (Biomass distribution)
• Amount of fruits x potential fruit size
Leaf Area Index
• Optimum for summer between 3 - 4
• This means 3 - 4m² leaves per m² floor
• Average 16 leaves = 1m² LAI
• LAI of 3 means 50 leaves per m²
• Higher greenhouse, more light, needs higher LAI
Depending factors on
optimum LAI
• Plantload per m²
• Amount of light
• Time of the year
• CO2 level
Plantload related to LAI truss small
beef (Admiro, 170 gr) traditional
greenhouse
100 kg CO2 / hour admiro
Density: 3.1
April 75 fruits per m² 36 leaves 1200 J
June 100 fruits per m² 48 leaves > 1600 J
August 85 fruits per m² 42 leaves 1500-1000J
September 60 fruits per m² 15 leaves, top is out
High modern greenhouse
• 10 % extra transmission > 10 % more density
• More CO2 5 – 10 % extra density
• For strong variaties lower density
• Generative and open variaties higher density
• Climate  Leaf lenght
Temperature strategy tomato & balance
AN,SR too cold:
-short internodes
-long leafs (rootpressure and low HD)
-fat head
-purple head
-too strong flowers
-pollination problems
AN,SR too warm:
-long internodes
-thin head, weak truss
-short leafs at high HD(dry air)
-long leafs at low HD
-hollow fruits
Peak too cold:
-chlorosis (too less transpiration)
-short internodes
-pollination problems
Peak too warm:
-length internodes:
1.Fast-Slow rise to peak
2.High-Low T-pipe
3.High-Low HD
-short leafs (at high HD)
-weak truss
-pollination problems
PN too cold (in relation to
plantload and lightconditions):
-fat, purple heads
-too strong trusses/flowers
PN too warm:
-thin weak heads
-weak trusses & flowers
-small tomatoes
-hollow fruits
-too long leafs
CO2 efficiency
1500 x 1000 / CO2 x CO2 = effect
From 350 to 450 ppm
1500 x 1000 / 350 x 350 = 12% extra growth
From 1000 to 1100ppm
1500 x 1000 / 1000 x 1000 = 1.5% extra growth
Light interception makes a
difference
Bron: Nederhof
Artiplant
Artiplant
Measuring light on different levels in
the crop
Increase of light interception
1.60
1.92
Advantages of removing top leaves
• Better penetration of the light to the lower level of
the plant (more activity)
• More assimilates to the fruits
• Higher production till 10% is possible but the
total LAI must be high enough, be carefull with
deleafing at the bottom of the plants
Effect of removing ( top leaves)
10% more production is possible
Disadvantages of removing top
leaves and too open plants
• Too low total LAI, reduction of production
capacity
• Too high radiation on young fruits, white fruits,
hard skin, splitting fruits
How does the plant grow?
Radiation
CO2
(plant) temperature
Feeding
Water
humidity
Functions
• Head = new development, future
• Leaves = factory producing assimilates
• Stem = pipeline (logistics)
• Roots = entrance, mouth of the plant
• Fruits = storage of assimilates
Principle
• Leaves with light and CO2 produce assimilates
• Assimilates can be used for:
*Further development of the factory
*Storage in fruits
“Growing is creating the right balance in this process”
Good balance
• 30% for plant
70% for fruits
• More to the plant means strong and nice plants but to low
yield
• More to the fruits means high production for the short
term but on the long term the plant will be weaker and
weaker till the factory is totally destroyed
Balance plant & light
Example: the total light is 1200 units per m²
Heads per m2
Light per head
For maintencance
For fruit
Light for the fruit per m2
Production
Difference
3
400
120
280
4
300
120
180
840
720
100%
0%
86%
-14%
Tools to keep balance
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Density of plants and LAI
Temperature
Light
CO2
Water and fertilizers
Mechanic
Variety, grafting
Density and Light
• A good base is 50% of the job
• Grow with a plan and a strategy
• The optimum system depends on the targets of
the producer
• There many ways to grow tomatoes
• Successful growing is just making as less
mistakes as possible
The GreenScheduler experience
crop
density
flower
speed
fruit
size
global
radiation
artificial
light
The GreenScheduler
Light
conditions
Balance
Variety
Crop density
planning
Result
Load and
production
Light - Temperature
• Available light is the limiting factor in most cases
• High radiation (600 Watt) gives extra generativity
• With density, temperatures,CO2 and irrigation we
can anticipate on this fact
• The optimum temp range for tomato is between
19 - 21 degree °C
DIF
• Difference between day and night temp has big
influence on the character of the plant
• A big DIF gives a greater development on the
fruits relative warm day, relative cold night
• A small DIF gives a greater development to the
plant relative cool day, warm night
Climate influence
Shorter leafs
dark color
thinner head
Right standing truss
longer plant
Thinner head
flowering high in head
Longer leafs
Lighter color
thicker head
Earlier ripening
Stronger truss
shorter plant
Thicker head
Flowering lower in head
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19
Longer leafs
Bigger fruits
20Stronger
21 22head
23
24
Generative or vegetative?
How can I recognize the condition of the plant?
Same greenhouse, same varytie: where are the
most and biggest tomatoes? Left or right?
Weak
Generative
Fast and strong fruitsetting
Condition of the plant
Generative
Vegetative
Condition head
Flat
Round
Flowering height
Height
Low
Truss position
Flat
Upwards
Bending truss tip
Bent
Straight / upwards
Position flower knot Bent
Upwards
Size of flower knot
Thick
Thin
Truss stem
Thick
Thin
Condition of the plant
Generative
Vegetative
Flower colour
Bright yellow
Pale yellow
Setting
Strong
Weak
Swelling fruits
Strong
Weak
Plant balance
Fruits
Leafs
Leaf length
Short
Long
Leaf volume
Open
Full
Virus image head
Much
Less
Condition of the plant
Powerful
or
Weak
Too strong
Weak
Condition of the plant
Condition head
Powerful, strong
Low speed
Powerless, weak
High speed
Powerful, thick
Powerless, thin
Anthocyaan / purple Much
Less
Virus image head
Less
Much
Internodes
Short
Long
Crop colour
Dark
Light
Stem
Thick
Thin
Setting speed
Low
High
Condition of the plant
Powerful, strong
Low speed
Powerless, weak
High speed
Plant load
High
Low
Leaf length
Stretched
Compact
Mechanic ways to manage
the crop
• Removing top leaves
• Deleafing strategy
• Truss pruning
• Clipping or twisting
Varieties - grafting
• Combination rootstock, variety
• Amount of tops per rootstock depends power in
the crop
The start
During the crop
Not bad
New start interplanting
Plant balance local light levels=
crop planning
• Analyze light conditions before you start and work it
outGreen Scheduler crop planning program
• Every area in the world and every season has his own
specific climate and light curves
• So experience is very usable and valuable, but a 1 to 1
copy from place to place is not per definition successful
Crop planning
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In the winter and spring we have to keep the
crop open enough and density is often too high
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In the summer we need enough power and LAI
to survive
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In autumn we need an open crop again….
crop planning
Grow with a plan with clear
and realistic targets
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Density
Speed of the crop
Production per week
Fruit size
Quality
Length and period of the crop
Green Scheduler crop planning!!
Other important factors
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Availability and quality of labour
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Technical possibilities
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“Green management” capacities
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Eliminate risks
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Keep it clear and simple
Thank you for your
attention!
www.greenq.nl