David Potereau, producer in Brittany

"Every time we can anticipate, we win"

David Potereau, a tomato grower near Brest, France, uses e-Gro as a crop prediction tool and to reassure himself about his production choices. Through his observations and exchanges with Grodan, he participates in the improvements of the software platform of his mineral wool slab supplier, whom he gladly calls a partner.

David Potereau set up as a greenhouse operator in Guilers (29) in 2003. After initial experience with a tomato producer in Finistère and then in the Netherlands, he decided to build a 1.5 ha greenhouse. Three years later, he doubled his surface, then added another 1 ha in 2017. His company, SCEA Le Petit Verger, now has 4 hectares of greenhouses entirely dedicated to tomato production.

In parallel, he joined forces in 2010 with two other producers to create La Serre du Glazik, a 7-hectare production site located in Briec (29), near an incinerator that provides hot water at 50°C. In 2008, David Potereau joined the board of directors of Savéol, the cooperative that supported his installation project from the beginning and accompanied him both technically and commercially. Today, he is vice-president and treasurer of the cooperative.

More than a substrate supplier
Right from the start, David Potereau opted to use rockwool, first with Grodan Expert slabs, then with 7.5 cm high Prestige slabs. Since this season, he has been using 10 cm high Prestige slabs for certain varieties.

The objective is to slow down the development of agrobacterium, which expresses itself less in the case of very generative varieties, and/or if the plant balance is well adjusted. "The presence of agrobacterium helps the development of roots in the most humid and darkest areas of the substrate. Therefore, to curb its development, you should try to direct the roots to dry areas. Because it offers a more aerated zone in the upper part of the bed, Prestige 10 cm seems to be an effective solution to contain disease development. The first results of the beginning of the season with Prestige 10 cm confirm this hypothesis," underlines D. Potereau.

He also explains that the highly variable climate of the Brest region requires a substrate capable of reacting very quickly. In this regard, rock wool is a well-adapted product.

But with Grodan, D. Potereau has found more than a substrate supplier. "Grodan's technical team offers tailor-made support and is available throughout the season. Together we are constantly looking for solutions to optimize watering and climate management."

Anticipating is winning
A year ago, D. Potereau installed e-Gro, Grodan's software platform. The primary objective was to have a crop prediction tool, both to anticipate sales at the cooperative level but also to forecast labor needs in a context where recruitment is becoming tighter. "These features of the e-Gro platform can still be improved, but they are useful because every time we can anticipate, we win," emphasizes D. Potereau with his hat on.

But e-Gro is also a decision-making tool for the crop manager who, thanks to the analysis of crop data, can have a schematic view of the balance of the plants. This tool complements the observations and measurements made daily in the greenhouse (scales, moisture meters, etc.). "It is not a matter of blindly trusting the computer analysis of the crop data, but of using it with a critical eye to reassure oneself about the choices made during the production process," says D. Potereau.

"It is also a basis for work and exchanges for our weekend meetings between personnel managers, crop managers, and company managers," continues D. Potereau, who recognizes that e-Gro has already achieved a fairly good level of performance in the "crop forecasting" and "crop analysis" sections. On the other hand, he believes that the "irrigation monitoring analysis" section still needs to be developed and that the dashboard for monitoring needs to be improved with more indicators to enhance performance and reliability.

"This work must be done in partnership with the Grodan teams. That's what makes a good relationship with a supplier who is always ready to provide technical solutions to complement its products. More than a supplier, Grodan is a partner we can build a future with," adds D. Potereau.

Today, thanks to the slab recycling solution offered at the end of the crop, Grodan products are fully compatible with Savéol's zero waste specifications.

For more information, visit

Publication date:

Receive the daily newsletter in your email for free | Click here

Other news in this sector:

Sign up for our daily Newsletter and stay up to date with all the latest news!

Subscribe I am already a subscriber