The use of clones in growing floral Cannabis is desirable because of the higher likelihood for uniform plant growth and the ease of establishment. Clones can also guarantee that a grower has all female plants, a condition that is preferable to produce floral tissue. When working with clones, a grower can begin vegetative growth indoors, before the threat of frost has passed, and then move the plants outside as the days get longer and warmer.
Growers also need to consider their plant spacing when transplanting outdoors. Cannabis plants need adequate spacing between each other to help minimize favorable condition for mold and fungus and to allow room for root growth and proliferation. Improper planting densities can also lead to increases in pest pressure or localized shading of plants by neighboring plants. For a grower to make the most of their available space, they need to understand how transplant time (which means a longer vegetative growth stage) and plant spacing will affect yield.
Linder et. al. (2022) looked at how transplant date and plant spacing affect Cannabis floral yield. This study looked at CBD hemp varieties, but the information is useful to recreational producers and broadly to fiber and seed producers.
The major findings were that earlier planting date led to more biomass. Planting width had a significant effect on plant width, with the largest planting widths producing the greatest plant width; this pattern held up over all planting width treatments with the larger width resulting in wider plants. The authors report a decrease in per plant yield of approximately 6.4 g for each day planting was delayed. The authors also report a decrease in yield per plant as planting width decreased, with the largest planting width (1.83 m) being 14% larger than the smallest planting width (0.91 m).
Crucially, the authors went forward with an economic analysis of how planting date and width can affect yield. Based on the results discussed above one would assume that early planting and large spacing would promote the best economic return. However, the large spacing means there is more unused space that could be used to produce flower. The best return was found to come when producers were able to transplant before June 5th and had plant spacing of 1.22 m. The early planting day takes maximum advantage of long days and warm temperatures. Spacing greater than 1.22 m in this study didn’t efficiently use production space; the lowest plant spacing (0.91 m) came with increased cost of clones, limiting the economic efficiency.
*Disclaimer: All work above is original to The Potanist and expresses our opinions and interpretations. We encourage growers to reach out before applying any perceived recommendations. Advice can be contextual, please consider your system and understand there is no “magic bullet” treatment.
