Inagro offers update on PlantGoed strawberry project

The Interreg PlantGoed project is focused on optimizing the cultivation of strawberry seedlings to meet the specific requirements of various cultivation systems. This article shares the status of three important experiments: a lighted spring trial with darkened Sonsation, an unlit everbearer cultivation with fresh Karima and Florice, and the cultivation of low-chill Fandango for an unlit spring cultivation. These experiments, conducted by Inagro in consultation with test garden partners PCH and Delphy, all investigate the effect of innovation during cultivation on the production and quality of the fruit.

Blackout's limited effect on Sonsation production
A trial was recently completed to evaluate the effect of darkening during cultivation on the production performance of Sonsation. The experiment aimed to darken and force the plant to flower more quickly so that it could be packed earlier and still build up sufficient cold hours before planting in early December.

Two darkening techniques were compared starting August 6: one where the day length was reduced to 10 hours and another where the day lasted only 7 hours. Flower bud examination under the microscope showed that darkening led to flower formation after just one week. In contrast, flower formation in the non-darkened planting material did not start until September 5. Despite this early advantage, no significant difference in production was observed last spring: all variations achieved a yield of 6 to 7 kg/lm with a harvest starting in early March.

Within this trial, there was also an object planted with long-stored planting material from 2023, which resulted in a clearly poorer fruit quality: only 58% Class 1 compared to 75% for the planting material from 2024. Notably, the older planting material began production a week earlier.

Fresh bearers' surprisingly strong start
In the unlit glass trial with the everbearing varieties Karima and Florice, planted at the beginning of March, production has been in full swing since April. Different types of planting material were grown in the greenhouse or in the daylight-free cultivation container and then potted without cooling; hence the name: fresh plant. The researchers compare the harvest progress and production potential with a classic cooled mini-tray plant.

The beautiful spring weather has visibly benefited this planting. The production of the fresh plants has been increasing steadily since the start. Since week 20, there has been a weekly yield of around 1 kg per linear meter, with a total production of between 3 and 4.4 kg/lm for the fresh Karima and Florice by May 28, compared to 2.6 - 3.2 kg/lm for the cooled control planting material. It is striking that the fresh plants still show plenty of red and green fruits and flowering, while production in the cooled objects seems to be slowly coming to a standstill. Researchers are curious to see how many types of fresh plants will achieve a sufficiently high and consistent harvest progress.

Not only is the production good, but the fruit quality is also excellent with the fresh plants. The sorting has been impressive so far, with a share of Class 1 fruits ranging from 80-92%, compared to only 75-80% with the cooled plant material.

Researchers are hopeful that this strong start to cultivation can be continued. In early May, a trial with similar objects was started to validate these findings.

Initiating the cultivation of low-chill variety Fandango
Next season, researchers will begin a new trial at Inagro on a more sustainable alternative to the classic illuminated spring cultivation: an unilluminated cultivation with the low-chill variety Fandango. This variety not only has a limited cold requirement, which means it can transition straight from the tray field into the greenhouse without cold storage, but it also requires considerably less light to produce. As a result, no lighting is required during cultivation, which drastically reduces energy consumption.

This cultivation strategy could become a promising alternative to the traditional illuminated spring cultivation with planting at the beginning of December, where the planting material often has to be packed early to gather sufficient cold hours in the cold store. This complicates optimal cultivation on the tray field and can affect the productivity of the planting material.

Currently, the mother plants are in the greenhouse and the first cuttings are forming. These will be cut outside on the tray field at the end of July, and the researchers will set up a fertilization trial. In this way, they aim to better understand the nutritional needs of this type of plant material and work towards a more efficient and ecological cultivation strategy.