Lots of things are happening in the cannabis breeding space, from sci-fi-sounding developments like synthetic seeds to the upcoming F1 hybrid seeds. The latter have been widely used in traditional horticulture, but in cannabis, this is relatively new. It's no wonder that Grodan wanted to test how these new types of seeds perform in their substrate to provide growers with the best tools to maximize their potential. Recent trials conducted at a research center in North America brought together expertise from both Grodan and F1 SeedTech to explore the interplay between genetics, substrates, and cultivation methods in cannabis production. The trials focused on evaluating stone wool and coco substrates with F1 hybrid seeds, examining factors such as cost, labor efficiency, and overall yield.
In the latest episode of Grodan's podcast, GroShow, Frank Janssen, Maikel de Bresser, Simon Charette, and Chad Rigby discuss the various insights and challenges from the latest trials, as well as the two that came before.
Researching F1 hybrids
"In 2017, the company decided to invest money in cannabis research," said Frank, Product Development Manager at Grodan. He explained that the company wanted to advance cannabis knowledge and help the industry reach a similar level as traditional horticulture.
In 2019, they started conducting trials from seeds, an approach derived from traditional horticulture, as no tomato grower starts from cuttings as the average cannabis grower does. These trials were also important in demonstrating the benefits and potential of F1 hybrids to cannabis growers.
One of the key advantages they agreed on was the ability to rely on a full-fledged R&D location. Instead of conducting trials in a greenhouse, the indoor settings of their R&D lab allowed them to focus on research rather than production.
In this third trial specifically, the companies compared stone wool and coco with two different F1 hybrid cultivars. Among other factors, they evaluated light levels, further refining conditions explored in previous trials to identify optimal settings for cultivation.
The first striking result was a significant increase in yields compared to the first two trials. Frank noted that one of the cultivars previously yielded 6–6.5 kg per square meter, but now it achieves 9–9.5 kg per square meter. Simon, VP of Operations at CRIC, highlighted how the gathered data showed the progression and ripple effects of the incremental improvements made throughout the trials.
Chad, Crop Specialist at Grodan, commented on the importance of conducting this research in North America, as it allowed them to use products and substrate configurations widely available in the local market. This enabled them to experiment with parameters relevant to the market and gather insights specific to the region. Additionally, it was critical to test how these varieties performed in different environments. While these cultivars were bred in greenhouse or outdoor settings, not every cannabis grower uses those methods.
The data collected by Grodan and F1 SeedTech is crucial not only for root zone management but also for genetic enhancement. The topics they are exploring are relevant not only for present-day cultivation but also for future applications, particularly regarding the transfer of knowledge from other markets into cannabis. While F1 hybrid seeds are a common method of propagation in other crops, they are still relatively new in cannabis.
Challenges of the experiment
At the same time, it would be misleading to say the trial results exceeded expectations with no bumps in the road, as the Grodan and F1 SeedTech teams faced challenges, as pointed out by Maikel, COO of F1 SeedTech. For example, if a plant produces massive flowers, it may become more susceptible to fungal infections, which they encountered during the last two trials.
Additionally, since they worked with autoflowering varieties, the crops reached harvest time quickly. This required adjustments to fertigation schedules and EC levels, ultimately contributing to increased yields. Due to the fast growth rate, Frank observed that it's not ideal to keep these plants in plugs for more than 5–11 days; otherwise, yields may decrease. Faster water and fertilizer absorption, along with faster root development, also necessitated more light—18 hours per day throughout the entire cycle. They noted that energy supply must always be considered.
These cultivation techniques applied specifically to growing F1 hybrids in stone wool. Frank pointed out that coco requires more frequent irrigation. While the final yields may be similar for both substrates, the resources required differ significantly. According to him, growing in stone wool is more resource-efficient. This is partly because plants grown in stone wool tend to be more generative, while those grown in coco are more vegetative. In coco, the plants develop more leaves, requiring additional labor for defoliation and environmental adjustments due to higher transpiration rates.
Future research
The year 2025 is shaping up to be a pivotal one for trials conducted by both Grodan and F1 SeedTech, with more research and tests in the pipeline. For instance, Chad emphasized the importance of examining substrate configurations and products popular in the market. He observed that growers are using smaller stone wool blocks during the vegetative phase to quickly establish a larger and more robust root zone, later transitioning the plants to larger blocks for flowering. He described this as an example of "plant momentum," where a plant develops much faster when provided with a large root zone during the vegetative stage compared to starting in a smaller block, which delays root development.
Looking ahead, Maikel mentioned that upcoming trials will explore whether topping autoflowering plants makes sense. While their assumption has been that topping should not be done, they have received market requests to test this scientifically. This will be one of the key focuses of their next trials.
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For more information:
Grodan 101
grodan101.com
F1 SeedTech
www.f1seedtech.com