Cannabis Tissue Culture 101Tissue culture cultivation represents a transformative approach to propagation in the cannabis industry. The science of tissue culture (TC) was commercialized roughly four decades ago and is widely used across agricultural sectors. Until recently, the technology had not been adopted by the marijuana industry, perhaps due to a lack of knowledge sharing between industries or the long history legal barriers. Today, the popularity of TC in the cannabis sector is a far different story.
Before TC entered into cannabis cultivation, propagation was done either by seeding or via cuttings. Physically planting seeds is time-consuming, with a high degree of variability in output, and gives the cultivator little control over the genetics of their crop. Using cuttings from a mother plant, was a development which cut down the propagation period and allowed farmers to essentially clone strains and plants with preferred traits. Yet, even clones come with issues. As any farmer will tell you, clones are prone to disease, pests, and infections. They still require time, space and substantial investment to get a plant to maturity.
In many respects, TC is an improvement over both conventional cannabis propagation techniques, faster than seedlings, more disease resistant than clones, all while providing near complete control over the preferred genetics of a crop. Importantly, TC is not as technical as it may sound. Do-it-yourself tissue culture kits are already packaged and sold to small-scale growers around the world. Third-party TC cultivation companies are also entering the market, managing the technical and logistical TC requirements for large-scale cannabis operations offsite.
How Does Tissue Culture Work?
The beauty of TC is that unlike conventional methods, it lets cultivators preserve a living specimen, almost perpetually, through minimal effort and using minimal space. Small pieces of plant tissue, even just a few cells, from cannabis specimens can eventually produce hundreds of identical clones.
All tissue cultures start life as a small cutting from a sample. The tissue sample is trimmed and goes through a crucial sterilization process. Once cleaned, the plant tissue goes in a dense nutrient culture which is typically an agar gel containing a carefully crafted nutrient, hormone and sugar mixture. The tissue culture controls the sample. Different hormone mixtures will trigger various stages of development for the tiny culture.
The culture can technically remain in a period of indefinite purgatory, until a time when the grower wishes to work with the sample again. Through the introduction of new hormones and nutrient-rich growing solutions, a cultivator can trigger growth, root development, and multiplication. When the plant is large enough to multiply, it is ready to be trimmed into literally hundreds of separate yet precisely cloned individuals.
These hundreds of samples follow a similar course until they are large enough to enter into a phase of hardening off and ready for planting. From one small tissue sample, a well-organized cultivator can potentially create hundreds of perfect clones, without any contamination from the mother.
The Benefits of Tissue Culture and the Drawbacks
The TC process requires clean workroom practices, which when followed guarantees the new plants are free from pests and disease while at the same time remaining genetically identical to the original cutting. For those familiar with cloning, you’ll appreciate producing genetically identical plants without the constant battle with infectious and genetic mutations carried down from the mother.
Unlike cuttings which require exhausting and perpetual maintenance, tissues are easily saved in small spaces over long periods, as needed. It can take a bit of logistical wrangling to handle the sheer number of tissues propagating at any given time, especially if multiple strains come into the picture, yet the benefits of TC will pay off with careful scheduling.
Technically, in a side by side comparison, cuttings still reach maturity faster than TC. A cutting from a mother plant should take roughly two weeks to reach planting stage, while tissue cultivation can take over a month to mature. For larger productions, the math still works out in favor of tissue culture, because TC has a considerable multiplication factor that traditional cloning methods simply cannot be replicated. Tissue culture cultivation produces efficiencies of scale that are incomparable to the conventional cuttings.
The benefits of TC go beyond only large commercial operations, and it can be of considerable benefit to smaller growers as well. With even just a do-it-at-home kit, a cultivator can take the genetic makeup of their crop into their own hands. There is still much to learn about TC's cannabis applications. As more commercial operations adopt the TC technique, there will inevitably be dramatic changes in the way we understand TC today.