Best Management Practices for Propagation and Kelp Amendment Benefits
For some growers plant propagation is a spring season chore, while for others it is a more of a constant cycle as they grow sprouts, leafy greens, and nursery crops. Each crop rotation offers an opportunity for an exceptional production cycle, whether a quick baby greens flush or orchard stock, and that process rests on having excellent, well-executed SOPs. Here are some best management practices for keeping plant propagation running smoothly and productively.
Cleanliness is the Best Defense
Ensure that grow facilities are kept clean from outside contamination (dirt on shoes, spores on clothes, etc.) and designate a clean/prep space before entering production rooms. In the production space, keep all surfaces, tools, and equipment clean and regularly disinfected. Results from Oregon State University in 2024 showed that 10% bleach dilution, 20% bleach dilution, and 1000 ppm hypochlorous acid dilution all can inactivate hop latent viroid disease (HLVd), which notoriously spreads most rapidly between plants when growing plants from cuttings.
How to Prepare a Well-Balanced Rooting Medium
Select a loose rooting material or compressed substrate like CANNA Rootplugs that provide sufficient pore size distribution for an ideal water to air ratio. Prepare the rooting medium, where the cuttings will be inserted, by soaking it in a dilution of a base fertilizer specifically designed for the balanced nutrient needed in early plant stages, generally an EC of 1-2.0 (mS/cm) and adjust the pH to 5.2-6.2 (for most plants). Avoid over-fertilizing, as this can damage plants and the substrate. Our researchers in Holland developed a blend for this stage, an all-in-one concentrate that can hold even calcium and phosphorus together (highly prone to bonding/falling out of solution), called CANNA Start.
Ascophyllum nodosum – The Known and Unknown Benefits of Kelp
Kelp extract has also been used during seedling and plant propagation, as well. Ascophyllum nodosum, kelp algae, has a long history of use in agriculture, with coastal communities using it as a fertilizer and soil improver for centuries. The benefits of A. nodosum have been supported by the literature, showing increased tomato yield and size (Ali et al., 2015). When it was sprayed as a foliar on vine grapes, it increased photosynthesis and stomatal conductance, alleviated water stress during hot periods, and was associated with a higher anthocyanin and flavonol content in berry skins (Salvi et al., 2019). Most importantly for seedling development and plant propagation, kelp algae has been well-known to support plant growth and stress relief during transplant, which was part of CANNA’s drive when developing our best kelp fertilizer: RHIZOTONIC.
Managing Plant Seedlings and Propagation Leaf Cuttings
If propagating supple, vegetative material like impatiens, poinsettias, or cannabis, take special care to maintain high humidity conditions, avoid wilt by covering finished plant cuttings, and work in small batches. Aim for a high humidity at 80-90%; misting and/or placing domes over the cuttings will help achieve high humidity. Gradually reduce the humidity to 60-70% as the plant grows more vegetative. When starting both cuttings and seedlings, maintain a relatively warm temperature between 75-80F and apply bottom heat through heat mats if possible. Low level, diffuse lighting is best, staying between 100-300 µmol/m2/s for light intensity.
To Your Next Successful Crop Rotation
Due diligence is required to ensure a high success rate of healthy plants, however, take solace in knowing that plants have evolved to persist with their genetic survival. Take notes, do your part, and encourage the natural strengths within the plant.
Abha Gupta, Horticulturist, CANNA
Abha Gupta blends her plant-science expertise with a passion for education and research to help cultivators and retailers dial in on the best CANNA products for their needs. Abha thrives on the diversity of her role while tackling everything from technical support to product development, and her knack for clear communication is critical when advising CANNA customers and the sales team. She also manages product quality monitoring and drafts technical content.
Abha is an outdoor enthusiast and lifelong learner who spearheaded academic hemp research, managed commercial farms, and served as a university horticulture instructor, in addition to being a certified yoga instructor. With a passion for music and seasonal fun, she loves to ski, hike, and relax at swimming holes where she lives in Vermont. Abha earned her bachelor’s degree from Cornell in environmental technology and her master’s in horticulture from Oregon State University.
References:
Ali, N., Farrell, A., Ramsubhag, A. et al. The effect of Ascophyllum nodosum extract on the growth, yield and fruit quality of tomato grown under tropical conditions. J Appl Phycol 28, 1353–1362 (2016).
Salvi, Linda, et al. Effects of Ascophyllum nodosum extract on Vitis vinifera: Consequences on plant physiology, grape quality and secondary metabolism. Plant Physiology and Biochemistry 139 (2019): 21-32.
Ocamb, C. 2024. Hop latent viroid in hemp. Oregon State University Extension Service.