How To Regulate Cannabis Growth With Crop Steering

Learn how to get perfect plant growth by controlling the environment.
16 July 2021
6 min read
How To Regulate Cannabis Growth With Crop Steering

Contents:
  • 1. What is crop steering?
  • 1. a. Plant growth balance
  • 2. The vegetative stage
  • 2. a. Crop steering in the vegetative stage
  • 3. The flowering stage
  • 3. a. Crop steering in the flowering stage
  • 4. How to know if crop steering is working?
  • 5. In conclusion

Crop steering techniques have been used for years and years but due to the recent legalization, cannabis has become one of the most lucrative businesses in the world, this is why companies are looking to grow more efficiently, thus increasing profits and at the same time improving product quality. And this is where this technique comes in. Crop steering consists of adjusting the growing conditions in order to reach certain outcomes in the vegetative and flowering stages of cannabis.

1. What Is Crop Steering?

Crop steering refers to the ability to adjust the temperature, humidity, and irrigation to steer your plants to the desired outcome. This occurs because plants have certain hormones that regulate growth in response to the growing conditions and stresses, these reactions are related to the seasonal changes plants are accustomed to in nature. So, crop steering basically uses these hormonal responses by manipulating the environment to achieve the desired outcomes during the vegetative and flowering stages.

Plant Growth Balance

Plants in the growth stage are in a state where the majority of the energy is directed towards leaf and branch growth but very little towards flower production while plants in the flowering stage direct the majority of the energy towards flower production and very little towards leaf or branch growth. 

 

Regulate cannabis growth with crop steering: plant growth balance

Crop steering can help you achieve plant growth balance, such as buds with more or fewer leaves and plants with more or less branching, for example.
 

This is why cultivators must keep proper plant growth balance between leaf, branch, and flower production; When talking about cannabis, plants that are growing too bushy or those that grow too much bud with very little leaves (which can slow down photosynthesis) are considered to be out of balance and if the plant is out of balance, it can end up affecting bud production and quality of the harvest. So the best way to improve overall plant growth is to optimize vegetative growth, ensuring the plants only produce enough leaves and branches to be able to support big, dense flowers without spending too many resources developing extra plant matter.

2. The Vegetative Stage

The vegetative stage is when cannabis plants develop the stem, branches, and foliage which, in this stage, are the predominant focus of the plant’s energy. As the plants grow, the increase in green matter results in an increase in photosynthesis capacity which helps prepare the plant for the flowering stage.

 

Regulate cannabis growth with crop steering: vegetative growth

Crop steering can increase green matter development which increases photosynthesis capacity.
 

Despite the vegetative being when cannabis plants usually develop the foliage and branches you can stimulate green matter growth ( such as leaves, stems, and branches) also during the flowering stage. 

 

So, for example, if you have a plant in the flowering stage that’s growing slowly or too compact, you can help it stretch out and increase internode spacing with the crop steering technique.

Crop Steering In The Vegetative Stage

In order to stimulate green matter growth (not reveg a flowering plant but increase branch and leaf growth), you need to simulate conditions similar to spring, allowing your plant to grow green matter more vigorously. The climate conditions include:

  • Lower VPD;
  • Lower Light Intensity;
  • And a stress-free environment.

In order to help you visualize these conditions, here’s a vegetative growth climate crop steering chart:

Climate Steering For Vegetative Growth 

Temperature  25 - 31°C
Humidity65 - 80%
Vapor Pressure Deficit (VPD)0.8 - 1.1 kPa
CO2500 - 800 ppm
Day/Night Temp. Difference0 - 12°C

Vapor Pressure Deficit (VPD)

VPD is the difference between the amount of moisture in the air and how much moisture the air can hold. This is very important because, as the VPD increases, the plant needs to absorb more water from its roots.

Apart from the climate conditions, there are also some irrigation conditions needed, which include:

  • Higher water content;
  • And Lower EC.

 Irrigation Steering For Vegetative Growth

Shot Size1 - 3% of substrate volume
Dry Back10 - 15%
Substrate Temperature22 - 25°C
Electrical Conductivity (EC)2 - 4 dS/m
Water Content55 - 70%
Irrigation Frequency6 - 9+ when lights are on

Shot Size 

The amount of water used to irrigate your crop, it's the amount of water you should water within every watering.

Dry Back 

The difference between water content in the substrate from the last irrigation to the next irrigation. Basically how dry the substrate gets between waterings.

Electrical Conductivity (EC) 

A measurement of how well water can transport an electric charge which is proportional to the amount of fertilizer in the nutrient solution.

 

Just remember that these are examples of the conditions that could promote green matter growth and the specific conditions will depend on the strain. It’s vital that you adjust the conditions and irrigation to your grow operation by experimenting with this technique and finding the sweet spot for the genetics you’re growing.

4. The Flowering Stage

During the flowering stage, the plant’s energy is focused on developing flowers and the plants slow down the growth of new leaves, branches, and reduce stretching.

 

Regulate cannabis growth with crop steering: flowering growth

Crop steering can help your plant focus all its energy on flower production, resulting in higher yields and better bud quality.
 

Now, just as mentioned before, if you feel like your plants are not developing enough leaves to support flower growth or you want more internodal spacing, for example, you can adjust the conditions in order to stimulate flower production.

Crop Steering In The Flowering Stage

In order to apply this technique to the flowering stage you need to simulate summer-like conditions, the flowering climate conditions include:

  • Higher VPD
  • And Higher light intensity.

Climate Steering For Flowering Growth 

Temperature15 - 25°C
Humidity40 - 70%
Vapor Pressure Deficit (VPD)1.0 - 1.5 kPa
CO2800 - 1200 ppm
Day/Night Temp. Difference0 - 12°C

 

Apart from the climate conditions, there are also some irrigation conditions needed, which include:

  • Lower water content;
  • And Higher EC;

Irrigation Steering For Flowering Growth 

Shot Size4-8% of substrate volume
Dry Back15 - 30%+
Substrate Temperature20 - 24°C
Electrical Conductivity (EC)5 - 12 dS/m
Water Content25 - 70%
Irrigation Frequency3 - 9+ when lights are on

 

Keep in mind that these are just examples of the conditions that could promote flower growth and the specific conditions will depend on the strain. It’s vital that you adjust the conditions and irrigation to your grow operation by experimenting with this technique and finding the sweet spot for the genetics you’re growing.

5. How To Know If Crop Steering Is Working?

In order for you to know if this technique is working, it’s essential you keep track of every plant, which is known as crop registration. Crop registration basically works by keeping detailed observations about your plants, probably being the most important aspect of this technique.

By keeping a record you can track how your plants react to the different changes in the environment and irrigation, allowing you to find the sweet spot for each genetic you’re growing.

 

Regulate cannabis growth with crop steering: crop registration

What should you keep track of when steering plant growth.
 

So, what should you keep track of? Well, this will depend on what characteristics you’re looking to improve but, in general, the most common observations are: 

  • Plant height;
  • Root development;
  • Stem diameter;
  • Internodal spacing;
  • Leaf and stem color;
  • Trichomes;
  • Plant vigor; 
  • And the size of the flowers.

By Keeping track of these characteristics after each grow cycle you can begin to understand how the different growing conditions and irrigation methods can affect each specific strain. This database can become a powerful tool for you to optimize yields and overall plant growth, allowing you to know exactly what to adjust for each specific genetic in order to get the best results possible.

6. In Conclusion

It can be hard to control all of the aspects mentioned without the right equipment but having all of these elements in mind can help you get better results even if you’re a home grower. Crop steering has been used for a long time but has recently been used in cannabis, showing excellent results.

 

If you have experience with crop steering, feel free to help fellow growers by leaving a comment in the comment section below!

 

External References

Growers guide to crop steering - Trym

Chlorophyll b as a source of signals steering plant development - Tyutereva, Elena & Dmitrieva, Valeria & Voitsekhovskaja, Olga. (2017)

Plant management for generative or vegetative steering - Nederhoff, Elly & Houter, G.. (2009)

16 July 2021
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