The number one mission for a vertical farm that is growing plants indoors is to mimic nature so they can grow the freshest and tastiest crops anywhere.

Every grower knows how hard it is to understand nature when growing a certain crop in a certain place. That’s because plants come from very different climates and growing conditions across the globe. Some of the plants that we eat flourish in the moisture and heat of the tropics, others in arid deserts or on steep mountain slopes. Some plants can acclimate on their own or be bred into new varieties that can grow in a different climate. But it’s a whole new situation when you are growing plants indoors in climate-controlled conditions in a city farm or vertical farm.

Philips researches all aspects that make up the ideal light recipe for a particular crop. But did you know that we also study a much broader range of factors to come up with the ideal growth recipe? This means that besides LED growing lights, we look at climate, CO₂, nutrients and substrates to see how we can make them work together most effectively. In this blog, I’ll tell you more about the major role that temperature plays in the storage life and yields of basil.

As LED lighting has become more and more popular among growers,, LED lighting technology has been rapidly evolving to meet their needs. Luminaires have become more powerful, efficient and versatile. Now they are getting even smarter! At Signify’s GrowWise research facility, we have been experimenting with a colour-controllable luminaire, which provides a whole new level of lighting flexibility for indoor farming facilities. The GreenPower LED production module 3.0 allows you to control both the colour spectra and light levels to create so-called dynamic light recipes. At GrowWise, we have been carrying out extensive research with these dynamic light recipes and would like to share four remarkable results that we have seen.

This is part two of our series of articles on how LED grow lights can influence nitrate levels in leafy greens. There are advocates on both sides of the issue. Some people want to lower nitrate levels in vegetables, while others want to raise them. Philips lighting Research, HAS School for Agriculture and Wageningen University carried out three simultaneous trials and discovered they could decrease or increase nitrate levels in the plants. 

The trials were carried out at the same time in winter, one in a greenhouse with HID toplighting, one in a greenhouse with LED toplighting and one in a city farm with LED lighting. The exact same crops of lettuce and the same fertiliser were used in all three trials. The crops in the city farm in particular had significantly lower levels of nitrates because they were grown consistently with the right amount of light every day.

The crops grown in the greenhouse under HID and LED both had higher levels of nitrate because they were affected by different climate conditions and lower light levels than optimum. The plants experienced cloudy, sunny, colder and warmer days, during which nitrates accumulated in the leaves of the plants. The results of this experiment confirmed that in addition to LED lighting, climate is an important parameter to control in order to maximise nitrate reduction.

For most lettuce crops, less than 1500 mg/kg of nitrates could be achieved just by tailoring the light recipe within a given growth environment. This did not affect yield or other quality aspects, such as shelf life and vitamin content. Combining the light recipe with a dynamic irrigation strategy could further lower these levels if desired. A similar strategy could also be applied in a greenhouse that uses supplemental LED lighting by adapting the climate parameters and lighting to work together. In the greenhouse trial with LED lighting, we achieved lower nitrate levels than in the trial in the greenhouse with HID lighting. 

It’s widely recognised that vertical farming has many advantages over traditional crop-growing methods. Simply put, despite relatively high setup and operational costs, the production per unit of growth area in vertical farms easily exceeds that in the most advanced greenhouses. But to consistently hit this level of production, you need to ensure that growth conditions are continuously at their best. This is where sensors and data play a pivotal role, and why they’re ready to transform the future of vertical farming.

The interest in growing plants indoors in vertical farms keeps increasing. But many investors who thought they could simply buy an empty warehouse, plug in some grow lights and turn out perfect heads of lettuce to make money have been disappointed. Here are a few key lessons learned from city farming expert Roel Janssen on successful vertical farm projects.

High productivity is important for a vertical farm – but getting the right quality of a crop is equally or even more important. With this in mind, it should not come as a surprise that our first experiments to grow strawberries at the GrowWise Center focused on achieving a sweet-tasting strawberry.  

Besides measuring productivity, we also measured the Brix values (sugar content) for two different strawberry varieties. It took us just over two months to grow strawberry plants from seeds. After that, we were able to pick large amounts of beautiful strawberries for about three months.

Normally produce from our facilities is used in the restaurants at the High Tech Campus. These strawberries, however, were so immensely popular that they never left our premises; they were eaten by our team as fast as they could ripen. 

There is an ongoing discussion about whether nitrates in food are good or bad for people’s health. Some want lower nitrate levels in vegetables, while others believe in the nutritional value of higher nitrate levels. Whatever side of the issue you are on, you may be interested in some new results from Philips lighting Research, HAS School for Agriculture and Wageningen University. By growing leafy greens under LED grow lights in an indoor vertical growing environment, researchers discovered that they could decrease or increase nitrate levels in the plants. 

In a few decades, indoor city farms or vertical farms have become popular for producing healthy food year-round in urban environments and harsh climates. Leafy greens and herbs are the most common crops in these facilities, but growers are looking to expand to a much wider variety of vegetables and fruits. In April 2019, we began a long-term series of research studies on high-wire tomatoes at our Philips GrowWise Centre. Our goal? Find the optimal high-wire cultivation strategy, light recipe and best-performing tomato varieties for city farms.