What’s the best growing media for cannabis hybrid seeds in the medical market? We partnered with F1 SeedTech to find out.

April 10, 2023

Most cannabis cultivators—whether focused on growing for the adult-use or medical markets—have two major challenges to contend with. One is to maximize yields to ensure profitability. The other is to maintain consistency through every step of the growing process, from seed to sale. The goal is to produce as many plants as possible in a given crop with the same flavors and potency—and to reproduce that consistency from harvest to harvest, year after year.

The path to meeting that goal looks different for different growers. Some brands are focused on pheno hunting—seeking new cannabis cultivars and breeding hybrid cannabis plants to produce select characteristics—so they can regularly release new strains to a consumer market that prizes novelty. Others work to perfect single strains favored by medical cannabis patients to alleviate a variety of symptoms, and to develop seeds that have all the predictability of non-cannabis crops like corn and tomatoes.

Cannabis clones have been popular for years as a means to accelerate production timelines and increase consistency across crops. However, storing clones in mother rooms or strain libraries takes up valuable space that could be used for bench rooting, vegetating and flowering cannabis plants. They also require input resources and manpower to maintain and are susceptible to viruses that can threaten whole crops.

Cannabis Hybrid Seeds and Stone Wool Growing Media

That’s why we partnered with F1 Seedtech, a cannabis breeder with facilities in the US, Holland, Spain and Israel, to explore how stone wool growing media can be used to enhance the consistency already bred into F1’s hybrid cannabis seeds. The trial was conducted at the Wageningen University and Research (WUR) in the Netherlands, and we found that cannabis hybrid seeds and stone wool are an excellent match. Together, they produce better results for cannabis cultivators—particularly for those growing medical crops.

“We realized that our products have several things in common—such as uniformity, reliability and predictability... Both our companies share a similar vision of moving the industry forward towards enhanced quality, higher yields and further professionalization.”

Frank Janssen


By using stone wool plugs to propagate the seeds before transferring them to Gro-Blocks, and by automating inputs through the e-Gro software system, we found F1’s seeds were 15% more profitable than clones. The hyper-consistency of F1’s seeds, when combined with the consistency of uniform growing media and crop steering, resulted in repeatable quality and yields.

e-Gro Closeup Image

“Stone wool is already widely used in high-tech growing, including cannabis crops... Now that it’s possible for growers and propagators to combine our stone wool growing media with equally dependable starting materials—F1 hybrid cannabis seeds—they can gain optimal control over their crop and take their production performance to the next level."

Frank Janssen


Also worth noting is the increasingly savvy cannabis consumer market. Consumers have a deeper understanding than ever before of different cannabis strains, cannabinoid profiles and terpene profiles, and how they can be used in a medical context. In the US, Canada and other legal cannabis markets, consumers are increasingly educated about the flavors and potency different strains should produce and the quality variation between brands. 

The grower who can execute greater cannabis cultivation efficiency and produce quality product at scale, and who can successfully market their product to both medical consumers and dispensary stakeholders, has an undeniable advantage.

Want to learn more about how seeds and stone wool can add up to greater yields, profitability and consumer satisfaction? We share more about our partnership with F1 Seedtech and the results of our trial at WUR in this white paper.  Get a closer look at how Grodan products contribute to a more sustainable agricultural industry  on our blog and podcast.