This document discusses optimizing the production of medicinal cannabis by balancing energy, water, and assimilate levels in the plant. It states that optimal production starts with a perfect assimilate balance between photosynthesis and respiration. Higher temperatures increase respiration and decrease the net assimilate balance available for plant growth, making the plant more susceptible to disease. Maintaining proper CO2, light, and temperature levels as well as stimulating nighttime evaporation to transport calcium to flowers can help balance assimilation and respiration for strong, resilient cannabis plants. The author notes there is more to discuss on these topics and announces a new research project on medicinal cannabis cultivation.

1. Optimizing the production of Medicinal
Cannabis
29 september 2021
René Corsten
r.corsten@delphy.nl
+31653374539

2. Introduction
René Corsten
r.corsten@delphy.nl
+31 6 53 37 45 39
Senior Consultant chrysanthemum (cut+pot)
Lisianthus, Bouvardia and other cutflowers
& Medicinal Cannabis

3. Humidity  → Temperature
Visiting LP’s there is a lot of attention
on humidity in preventing Botrytis, but
less attention on temperature
General growing strategy is a low
humidity & a high temperature
But is this logical

4. 3 balances in optimizing the growth of your
Medicinal Cannabis
Energy balance
Water balance
Assimilate balance

5. Net assimilate balance
All 3 balances are important,
however for Delphy optimal
production starts with a
perfect assimilate balance

6. Assimilate balance
Photosynthesis (assimilation – making of sugars)
- Light
- CO2
- Humidity
Respiration
(dissimilation –
burning of sugars
for energy)
- Temperature

7. So what happens when the temperature is
higher and the light level is still the same?
Assimilation is not increasing
Dissimilation is increasing
Result:
→ The net assimilate balance (assimilation minus
dissimilation) = getting lower
→ Less sugars are available for making strong leaves,
flowers, roots, …….. Etc.
→ The plant gets more funerable for diseases

8. 24hour temp radiation radiation
department sum level Total Optimal
outside inside hours mol/m² joules/cm² 24hour temp
A very sunny day in a greenhouse Generative 3000 45,2 3000 28,5
A winter day in a greenhouse with 400 umol LED Generative 600 400 12 26,3 1748 25,4
Indoor growing with 600 umol LED Generative 600 12 25,9 1722 25,3
Indoor growing with 1000 umol LED Generative 1000 12 43,2 2870 28,2
Indoor growing with 600 umol LED Vegetative 600 18 38,9 2583 27,5
Indoor growing with 1000 umol LED Vegetative 1000 18 64,8 4306 31,8
radiation influence C per 1000 Joules 2,5
basic-temp C 21
18
20
22
24
26
28
30
150 350 550 750 950 1150 1350 1550 1750 1950 2150 2350 2550 2750 2950 3150 3350
etmaaltemp
stralingssom/dag
relatie etmaaltemperatuur en stralingssom

9. Is this all

10. No! Also important: CO2 levels

11. But my plant is healthy and I still get Botrytis?

12. Calcium and evaporation
During the day a lot of evaporation – it can go up to 6
l/m2/day
Calcium is then transported to the evaporating plant parts -
the leaves, not the flowers
For Calcium transport to the flowers you need root pressure
and night evaporation
By first increasing the root pressure during the night and then
stimulating evaporation, you can transport Calcium to the
flowers, so that they become stronger and more resilient
against Botrytis
This can be achieved by supplying and removing moisture
from the indoor cultivation location / greenhouse

13. 10 minutes is short, a lot more can be told about the cultivation of
Medicinal Cannabis, for instance about:
The influence of Humidity on the net assimilate balance
Night evaporation and Calcium transport
Which technology is needed for a perfect climate control when
you grow indoor
How to use your black-out screen in a greenhouse
The influence of light and temperature strategies on the
design of the plant
Making a good vital cutting with a good motherstock strategy
The rooting of cuttings
Pest and disease control
Nutrient recipe strategy
…………. etc

14. But I don't want to withhold this information from you
2022 we start a long term research project at
Delphy Improvement Centre in Bleiswijk on
Medicinal Cannabis with several partners