Custom-fit lights for custom-grown veggies

In an earlier study conducted by The Chef's Garden, lettuce grown under Sollum lights took an average of 28 days to achieve target mass compared to 35 to 40 days for lettuce grown in a regular greenhouse.

Sollum's programmable smart lighting solution also enables The Chef's Garden to make precise adjustments to lighting to achieve specific objectives. We recently partnered with their research and development team to test the possibilities.

One experiment studied the effect of light spectra on the growth and flavour profile of basil, green lettuce, red lettuce and radishes, comparing the balanced spectrum provided by Sollum lights with a competitor's LED lighting system, which provides more red and far-red (FR) light. Among the key findings:

- Radish grown under Sollum lights achieved The Chef's Garden's target size for garnishes. In a sensory evaluation, the radishes earned a higher composite score from panelists compared to the competitor's system and the control greenhouse, including higher scores for appearance, colour, texture and flavour.

- In most of the experiments, red and green lettuce varieties exhibited higher fresh shoot weight, leaf length and leaf width with Sollum lights. In the first test, red lettuce fresh shoot weight was 40% higher, leaf length was 18% longer, and leaf width was 3% greater.‍

- The flavour profile of basil varied between Sollum's and the competitor's systems, confirming that light quality can affect taste. This is good news for growers using Sollum lights because our technology enables them to adjust spectrum and intensity to produce a premium product and target different markets. For example, the food service industry may prefer basil with a strong taste, while consumers may prefer a mild, sweet flavour.

The second study experimented with adding blue and far-red light to red-pigmented lettuces a few days before harvest to see if growers could delay anthocyanin accumulation until the end of the production cycle. While anthocyanin provides valuable protection for plants, it also slows photosynthesis in some crops. With the right light recipe, a grower could hypothetically accelerate a plant's growth and then promote anthocyanin accumulation in the last few days – which would also deliver health benefits to consumers because anthocyanin is an antioxidant.

The study confirmed that the lettuce grew faster with the addition of far-red light, but at the expense of anthocyanin accumulation. It also found that by adding blue light at the end of the cycle, you can increase anthocyanin accumulation.

“These results show how different light recipes can be used at different stages of the lettuce growth cycle to achieve desired characteristics and optimize growth,” says Rose Séguin, a Sollum Technologies agronomist. “The next step will be to explore far-red's effect on leaf thickness and lettuce body as the lettuces need to hold up to garnishes and dressings.”

“There as so many possibilities with Sollum's lighting solution. We're pleased to be able to test them with a grower whose imagination and dedication to quality are second to none.”