The fact that sapflow and stem diameter measurements help with gaining insights into the plants is already known in traditional tomato, cucumber, horticulture, but also in Cannabis these sensors can help tremendously to gain more knowledge how the plants really reacts towards all external influences in the greenhouse.
"2Grow specialises in 2 sensors: sapflow and stem diameter sensors," the company explains. "Using the sapflow sensor we can measure activity and transpiration, with the stem diameter sensor we can measure the growth, stress and the buffering of energy levels."
"As the diameter sensor measures stress among other variables, it is possible to visualize how far the plant can be pushed without weakening and limiting further development. If we look at the measurements of honey tomatoes, the most sugary and tasteful tomatoes in the world, we see that the variation/stress during the day is far higher than the traditional flesh tomato where taste is not that important."
"There is a grower that cultivates these tomatoes with an EC of 16, this is very stressful for the plant and using the measurements they make sure that they don't push it over the edge and start weakening and ultimately cost production."
"This kind of stress has a big effect on the amount of sugar that gets transported to the generative area's such as the flower/fruit as the plant is trying to save itself for reproduction."
VPD, the vaporization pressure deficit, is known to be an indicator for stress. Traditionally each plant has its own number when the plant starts stressing. For Spathiphyllum for example this is 1.2 kPa.
"This variable is one of the primary influences on the diameter, they have an almost perfect negative correldation. So using the diameter measurement combined with the sapflow we can manipulate the plant towards the optimal growth conditions and control the climate according to the true needs of the plant."
"For example, in the graph underneath you can see through the shrinking diameter that the plant had a lot of stress during the day, with its lowest point at 8:00pm. The lowest point in stem diameter is most often the highest point in VPD, thus the most stressful moment on the day."
"This can be a good strategy of growing more generative and push the plant towards its limits to augment quality and production, however it did not recover towards the evening. As the plant cannot put all his newly acquired assimilates towards the flowers/fruits, this can weaken the plant and will cost some production. The grower should have taken action to help the plant, by visualizing and facilitating recovery he can still grow generative/stressful but without losing production."
As the cannabis plant uses the excess in sugar to develop the important terpenes, flavonoids and cannabinoids that we know and like, it is very important to monitor this closely and push the plant to the limits of stress without weakening the plant. Through the extra stress in the flowering/generative period, there will be a higher quality of flowers (taste, scent, cannabinoids) and more production. And by having more control of your growth during the vegetative/growth phase you can increase/limit growth through indicators where the plant truly puts his energy and controlling it with climate conditions such as irrigation and VPD.
This is just one example on how we can use these sensors to gain better knowledge into the plant.
Other things include:
- Setting irrigation on the true needs and develop a better root system through optimized aeration of the roots, which will eventually lead to more vital plants and more production.
- Control the energy priorities better of the plant: require more plant growth or want to push all energy towards the flowers in the flowering period, this is easily monitored using our system.
- See plant health from a distance, we have consultants who use our system to monitor the plants from home/office. .
- Shorten the feedback loop between us and the plants , which enables to see every influence on the plant in real-time and adjust them according your and the plants needs
The company can be visited at the Canadian Greenhouse Conference in October at Booth #1255.