A uniform crop and a uniform growth from propagation to harvest. It is the dream of every medicinal cannabis grower, but difficult to achieve in practice. Thanks to the new dynamic light recipe developed under Philips grow lights, the grower can steer for uniformity during propagation. This is a benefit which will pay off till harvest.

A good, uniform propagation is the holy grail for every medicinal cannabis grower and can make an enormous difference in yield and quality. The application of a new dynamic light recipe during the propagation with the right levels of red and far-red will give the possibility of shortening the full growth cycle. Depending on cultivars, this could be several days per cycles, with the possibility to boost the vegetative phase too. Just as important is the fact that with this recipe, growers can make the most efficient use of their lighting with the Philips GrowWise Control System as shown in recent joint research performed by Signify and Wageningen University & Research.

“Young shoots root best when you use the right combination of red/far-red lighting. A standard light recipe does not contain far-red. That means that you have to add some far-red during the propagation phase to achieve synchronized rooting”, Celine Nicole, plant specialist Philips horticulture LED solutions, explains. This will lead to uniform root development, root volume, and shoot length, and these are the criteria for a uniform vegetative and ultimately flowering phase.

This eventually leads to plants of equal composition and size, that all receive the same amount of light during the growth phase. In current practice differences often occur after propagation, meaning that smaller plants are shaded by their neighbor. “This means that growers do not make optimal use of their applied assimilation lighting, which is a waste of the investment”, Nicole states. She adds that it is “essential to adjust the other climate aspects to the light intensity and spectrum applied”.

Users of Philips grow lights receive tailored advice about the exact composition of the dynamic light recipe. This is always a matter of customization, tailored to the grower’s goals, such as maximized production or as high as possible quality of compounds.

Signify does reveal that timing is crucial. So, the root development is stimulated with a specific light recipe during the first week of propagation. The recipe (spectrum and intensity) is adjusted afterwards to stimulate the development of the shoots. The choice of cultivars also plays a role in the lighting advice, of which there is currently a great deal of variation in cannabis cultivation. Signify expects the dynamic light recipe will enable growers to refine and improve their assortment through cultivation trials.

In current practice, hormones are mostly used for the rooting of new plants. However, this is forbidden by law in several European countries. The use of dynamic lighting offers a solution in this case, but this lighting strategy can also be combined with the use of hormones. Although it is essential for growers to know which hormones they are applying, due to the great variation, according to Nicole.

‘Good explanation’
“I am very happy with our findings from the trials into medicinal cannabis that we have performed in close collaboration with Professor Leo Marcelis and PhD Sae-Tang of Wageningen University & Research. It is great that we can now control uniformity during the propagation phase, and that we can explain to growers how and why this works. This new knowledge will elevate medicinal cannabis cultivation to the next level”, according to Nicole.