“Temporarily extending daylength increases cannabis yield by up to 20%”

Signify and Wageningen University & Research (WUR) have created a light recipe that extends the flowering phase of medicinal cannabis, leading to higher yields. By upping the photoperiod – that is, the length of daylight – from 12 to a maximum of 18 hours per day, the yield can increase by up to 20%. Timing is crucial. It must be a pre-harvest treatment, and the right moment differs per cultivar.

Dr. Céline Nicole, a senior plant specialist at Signify, says: “We have developed and patented a ground-breaking light recipe with which we can safely extend the daylength without interrupting the flowering phase. To successfully achieve this, the right moment and length of time in which to raise the light sum is very important.” Applying light for a longer period of time and generating higher yields means that growers can improve their return on investment on their LEDs.

Multiannual research by Signify and WUR

These new insights result from many years of joint research between WUR and Signify, conducted at WUR’s research facilities. This included experiments with different variations in light intensity, length, and spectrum. The research targets specific challenges in the cultivation of medicinal cannabis, such as the management of the flowering phase, the uniformity of the crop, and the homogeneity of the cannabinoids.

Professor Leo Marcelis, research leader and supervisor of PhD student Wannida Sae-Tang, says: “It is fascinating to see how the cannabis plant responds to the different aspects of light, i.e., daylength, intensity, daily light integral, spectrum, direction and how it interacts with other growth conditions.

Growers will see tangible benefits from them.” Nicole adds: “Our lighting strategy of increasing the photoperiod from 12h to 18h with an installation delivering 1000 µmol/m2/s, in practice, would make the crop experience a light sum equivalent to a lighting installation of 1500 µmol/m2/s. And therefore, the grower would be saving a lot on lighting fixtures as well”.

The optimal spectrum

The second important result from this research concerns the light spectrum: using certain colors can influence the potency of cannabinoids. Though unable to share confidential details about the light recipe, WUR and Signify are certain that it will help to reach a constant level of cannabinoids. Controlling the potency is essential in medicinal cannabis cultivation. Dr. Nicole says certain colors in the spectrum affect and safeguard the potency within a certain bandwidth.

From research to application 

According to Dr. Nicole, growers will be able to put these new insights into practice right when starting their new growth cycle. “One of the consequences of longer lighting is that you also have to adjust other aspects of your cultivation, like climate control, irrigation, and nutrients. As long as you adjust these parameters for the photoperiod, our research shows that you would achieve accompanying results.” The final trial of this research will be performed and finalized this autumn, after which Signify will share more information about its outcome.