Hortitool Consulting

Building an international berry consultancy

As a young graduate, Duarte became farm manager at Sunny Morangos in Faro, overseeing a Dutch-invested strawberry operation growing Elsanta. There, he developed his knowledge of substrate production and techniques such as flower mapping, while also supporting Meteor Systems’ hydroponic projects.

It was here that Dutch consultant Dennis Joosten, of Joosten Horti Consult BV, recognised Duarte’s potential and encouraged him to become an independent consultant. Duarte took this advice on board and, by 2012, was privately advising growers. He officially launched Hortitool Consulting in 2014, starting in his home country of Portugal but soon expanding across Europe and North Africa through frequent visits to growers in neighboring countries.

“I like travelling and getting to know other cultures. When you travel, your vision of the world changes, and your opinions change as well. One trip can change your life,” says Duarte.

During this period, Duarte increasingly focused on blueberry production, initially working with the crop in Portugal during a period of substantial investment and rapidly increasing consumer demand. He later worked alongside Italian agronomist Marco Butera, of Better Berries, helping growers transition from conventional soil production towards substrate systems and newer genetics. The pair also established a dedicated blueberry school, supporting around 15 client farms.

Rather than offering isolated technical fixes, Duarte also encourages growers to consider the farm’s “bigger picture”, connecting crop performance with operational and commercial viability. Describing himself as an “architect of strategies for growers” as much as an agronomist, he helps soft fruit producers understand how decisions concerning irrigation, nutrition, climate management, genetics and production systems ultimately influence yield, fruit quality, labour requirements and return on investment.

Taking Plant Empowerment beyond the glasshouse

Duarte believes that investigating how a framework developed largely around highly controlled glasshouse production can be adapted to polytunnel systems present an important challenge.

“Much of the world’s horticultural production takes place under plastic structures rather than sophisticated glasshouses. Understanding which Plant Empowerment principles can be transferred directly, which need to be adapted and how we can measure the relevant plant and environmental responses under these less-controlled conditions could have considerable practical value,” he says.

“I explained to the speakers and my colleagues at the Summer School that we need to keep moving outside our comfort zones. That is how we challenge what we think we know, learn new techniques and continue improving our skills.”

Exploring the potential of Brix

One topic discussed at the Summer School by Plant Empowerment consultant Mark van der Werf that particularly caught Duarte’s attention was the measurement of soluble solids in plant sap using a refractometer, commonly expressed as degrees Brix (°Brix).

Following the course, a dedicated WhatsApp group with fellow participants has been used to compare Brix measurements and gather field observations across different crops and growing conditions. His interest in the subject subsequently led him to write an article about Brix for the specialist platform Italian Berry.

Brix measurements obtained with a refractometer provide an estimate of the concentration of soluble solids in expressed plant sap. Although sugars can represent an important component of these soluble solids, the reading can also be influenced by other dissolved compounds and by factors including plant species, tissue sampled, time of day, water status, environmental conditions and sampling methodology. For this reason, Duarte sees Brix primarily as an additional field measurement that should be interpreted alongside other physiological, nutritional and environmental data rather than as a stand-alone indicator of plant health.

“Brix gives us another piece of information about what is happening in the plant. What interests me is not simply whether the number is high or low, but why it changes, how repeatable those changes are and whether they can be related to other measurements of crop performance and plant physiology.”

Putting the theory to the test

“We are still at the stage of asking questions. A Brix reading by itself cannot explain plant physiology or predict pest pressure. But if we measure it consistently and combine it with information on climate, irrigation, nutrition, plant water status, pest pressure and crop performance, perhaps we can begin to understand whether there are useful relationships.”

For Duarte, this reflects a broader principle behind his approach to agronomy: field observations should generate questions that can subsequently be tested with better data.

“It will be interesting to see whether we can develop some research together. Rather than simply accepting or rejecting the theory, we should test it. Let’s collect the data, compare different crops and environments, and find out where the relationships are real, where they are not, and what we can learn from them.”