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In the sub-project, the idea was that growers could use sensors to receive alerts, for example, via a text message if the plants' habitat is not good. In addition, sensors that measure humidity can be used to make better decisions about when it is time to water the municipality's plantings — and thus the municipality can avoid both unnecessary irrigation and dehydrated plants and thus save money.

On the hill below the Max IV lab at Brunnshög in Lund there is an area with cultivation lots. The area has a clear sustainability character and enthusiasts with their own plantings grow flowers and vegetables. Here the growers' association also had a greenhouse where Mikael Hellberg and Janine Österman grew tomatoes, peppers and cucumbers, among other things. These crops in the greenhouse are sensitive to high humidity and high temperatures and therefore the sensors alerted the growers via text message when there was any value that was not good. When the alarm went off, the indoor environment was regulated by opening doors and windows.

“We have measured very high temperatures and when temperatures get so high, the plants stop working well and are easily damaged,” says Anders Heberg, sub-project manager from Sensefarm in an interview in 2018. With this type of measuring equipment, you get better harvests and you also avoid using poisons against pests that can take hold when the habitat is not good.

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The Bastion Uppsala park was built near Malmö Central Station in 2018. Among the trees, grasses, bulbs and perennials, the municipality dug down measuring equipment to monitor so that the plants received the right amount of water.

“In this park, we have installed moisture meters in two places,” says Sam Madsen from the service administration in Malmö in an interview during the opening ceremony. We have chosen

to put them in two different soil substrates to be able to measure which substrate holds moisture best. In each substrate there are two sensors that measure the moisture at different depths so that we can also see how much water penetrates into the soil.

The measurements were then passed on and in this way the street office could read on its computers when it was time to water the plantings. The results also provided data on how much water penetrates down to the roots of trees. For cities that have very large areas with crops to manage, it can save a lot of money if you water when the time is right and not when you think it is time.

In order to be able to receive signals from a sensor in the planter to a computer, a sensor network is needed, among other things. In both Lund and Malmö there are LoRa networks that are part of the test bed for the project. The sensors are not connected all the time, but send their readings at preset time intervals. This allows the batteries to last for a very long time, which is a great advantage as you do not have to spend so much time on battery changes.

Through the project, the City of Malmö was able to increase its knowledge of irrigation. Among other things, it was observed that the substrate with pumice dried up faster than the one without pumice — but also that it absorbed moisture faster when it rained. Sensor data also provided insights into how quickly the beds dry up and how much water is needed to reach the deepest sensor. It was also possible to see how much rain is needed to reach down to the roots of the plants. Overall, the measurement also means that the municipality can save time and money.

“In a new planting, it can take several days to water everything through with a spreader,” Torun Jorde, section manager at the service administration in Malmö, told me in a 2019 interview. With sensors we can follow up on the result of watering. We can also, for example, see if the rain that comes has been so good so that we can postpone the next watering. Each saved watering in a planter of this size saves a lot of time and money.

In 2019, the service administration in Malmö had mainly had sensors among the summer flowers in the flower urns in the central moldings between roads in the city.

“If we manage to save, for example, two waterings in a season, it means SEK 30,000 less in costs,” Torun Jorde said. Our flower urns are watered by subcontractors and each watering takes three days. With sensors, I can instantly see that they are outside watering and I can follow so that they have watered enough. It is easy to detect if an area is forgotten, which could happen, for example, during holiday times. In addition, we can easily see if it has rained enough — so we don't have to go out in the middle of the road unnecessarily.

The sensors were also deployed in a roundabout covering the soil with gravel to reduce evaporation, thus providing important knowledge of how well that method worked.

“We can also use the humidity levels as a quality assurance,” Torun said. Should it be plants that do not make it, we can demonstrate to suppliers that it is not because we watered too poorly.

If humidity levels anywhere in the city became too low, the service administration received alarms via computer or text message.

“The metrics that the sensors give us allow us to better follow curves to predict when we need to water, but also allow us to better know what is wet or dry. I hope, however, that they evolve so that they become smaller and thus more manageable and easier to hide. I am convinced that the sensors are here to stay,” Torun Jorde concluded.

What was the result?

In the urban orchard in Lund, the sensors measured humidity and temperature and users would be able to log in and see the development over time. If the values were too high, alarm signals would also be sent out via users' mobile phones. However, in the first attempt, the test pilots did not understand the web interface — which led Sensefarm to adjust so that it subsequently worked well.

The part of the experiment conducted in Malmö examined how to monitor plants and trees in a newly planted park. This was successful and led to Sensefarm being able to develop a working service. In Malmö, the municipality continued to use sensors in flower urns that were deployed at various locations in the city.

How is the project taken forward?

Sensefarm has continued to work on its product and, among other things, delivered sensors to the West Link in Gothenburg and to the large newly planted tree at Katedralskolan in Lund

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Facts sub-project Green space management

The project is a sub-project of the SOM project is part of the Strategic Innovation Programme for the Internet of Things, IoT Sweden, which is funded by Vinnova. Anders Trana at Future by Lund was the project manager for the entire project. The project started on 1 September 2017 and ran until December 2020.

‍Project Time: 2017-09-01- 2018-10-31

Project Manager: Anders Hedberg

Project partners: Sensefarm, Lund Municipality, Malmö City, Growers Association Brunnshög

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Caption, big picture: Mikael Hellberg and Janine Österman from the Brunnshög growers' association in the greenhouse that was operated using sensors.