Handelskwekerij Gebr. Valstar B.V.

Gebr Valstar B. V. is a family business founded by Jac Valstar in 1978. The two branches in Maasland and Damsigt B.V. in Roosendaal are now headed by Jorgen and Oscar Valstar.

Gebr Valstar B. V. supplies Calathea, but also grows and propagates this decorative pot plants. The company has its own Star Collection of which many different species of Calatheas originate from the jungle of Brazil. Own mutants have been added to this Star Collection. Calatheas are supplied by exporters throughout Europe. In addition, they are sold in America and China.

Both in Maasland and in Roosendaal Gebr. Valstar has a company of approx. 5 hectares. Both companies are very modern and well equipped for the cultivation of houseplants. Automation and logistics have been largely implemented. As a result, human hands are no longer needed to carry out cultivation operations in the greenhouse. The company has an ingenious camera system for the sorting process. This allows for an optimal quality and uniformity. Gebr Valstar focuses on corporate social responsibility in the areas of environmental/waste, energy, crop protection products, fertilisers and nature management, in a way that makes it possible to incorporate it in a responsible and practical way within the business operations.


Rainwater collected in water basins is being utilized. If really necessary, surface water or tap water can be used as well.

The plants get water as needed and are supplied with the required water by means of an ebb and flow system. Thanks to a closed system, all water that has not been absorbed by the plants is collected in water silos, cleaned and used again: 100% reuse. Thanks to this recirculation water and fertilizers are optimally utilized.


Nature Conservation

Gebr. Valstar tries to combat disease and pests within the nursery by applying biology (natural enemies) to minimise the use of plant protection products. Gebr. Valstar also works with a nature management plan to protect and promote nature in the neighbourhood. It aims to make production methods and waste management more environmentally friendly, in particular to protect the quality of surface water, soil and landscape and to preserve and/or promote diversity of flora and fauna.

Examples: ditch edges are mowed and not sprayed, breeding sites of birds are spared, when ditch edges collapsed they are repaired (according to the policy of the Hoogheemraadschapm, the High Water Board), ditches are well maintained and no water is discarded into ditches.


Gebr Valstar is consciously working on reducing energy needs and energy consumption by:

– maintenance of the greenhouses, machines and appliances (CHP, screen cloths etc.),

– installing fixed film on the side walls every year,

– good insulation of the transmission lines to minimise temperature loss,

– using its own CHP and using the heat again and again to reduce the use of fossil fuels.

Both sites are energy-efficient. The Roosendaal site uses residual heat from a waste processing company.

The waste from both sites is separated, reused and/or disposed of in accordance with the waste plan.

Crop Protection Agents Kg Active Ingredient: 

Provides insight into the use of plant protection products. Red stands for substances with a high environmental impact, orange for substances with a low impact on the environment, green for substances with a low impact on the environment (Source MPS-A).

Energy (GJ):

Provides insight into the use of the amount of energy. (Source MPS-A)

Fertilizers (KG) Nitrogen and Phosphorus Consumption:

Provides insight into the use of Nitrogen and Phosphorus. (Source MPS-A)


Gebr Valstar employs 45 people permanently and employs temporary staff. All these employees (men, women, ethnic minorities, Dutch) are treated equally and have equal opportunities within the company. The working method is based on the conditions described in the Collective Labour Agreement for greenhouse horticulture. Employees therefore have an employment contract, providing them with income security.  The temporary employment agencies working here also meet the requirements of the Collective Labour Agreement.

Within the company, a great deal of attention is paid to the safety, health (hygiene), welfare and training of employees. This is aimed in particular at employee involvement and responsibility. There is also an occupational health and safety plan and there are various company first respondents.


Did you know that flowers and plants have a healthy effect on people?

  • Plants provide air purification..
    People breathe in air, take out oxygen and breathe out carbon dioxide. In the case of plants it is the other way around. During photosynthesis, plants remove carbon dioxide from the air and convert it back into oxygen. The amount of oxygen in the air is increased by the presence of plants, which makes breathing easier.
    Air-purifying plants can absorb harmful substances from the air through their leaves. These harmful substances are then stored and broken down in the plant’s roots. These plants can also break down dirty odours, so they are actually natural air fresheners.
    For the sake of clarity, every (indoor) plant produces oxygen, but not every plant also purifies the air. Air-purifying plants are e.g. the Spathiphyllum, Calathea, Hedera helix (ivy), Areca palm and the Ficus. For many plants we do not yet know to what extent they have an air purifying effect since they have not yet been tested.
  • Plants ensure a better concentration and a reduction of stress.
    Plants create a relaxed and better atmosphere, also at work.. Plants make the workplace a more pleasant place to work.
    Apparently there is even a relationship between the presence of plants and the productivity of employees.
    Moreover, the presence of plants has a positive effect on the creativity and concentration of people.
  • Plants reduce the dryness of the air
    The dust content and humidity in the house are strongly related with each other. The dryer the air, the more dust. This can cause symptoms such as a tickling cough, dry skin, headaches and irritated eyes. By watering plants, it finally evaporates again through the stomata in the leaves. Plants can thus increase the humidity of the air, which therefore benefits the air quality.
  • Plants provide a pleasant and warm feeling
    Research has shown that plants are good for people in various (subtle) ways. They play an essential role in creating a pleasant, natural and quiet environment in which to move, work and/or relax.
  • Did you know that flowers too have a healthy effect on people?
    Flowers can brighten up any room in a magical way. They give meaning to our emotions such as love, joy, comfort, compassion and sorrow. Flowers provide a relaxing effect on our constitution. They provide positive energy in the home and a warm feeling. In short, everyone is just very happy about that!



The Dutch greenhouse horticulture sector is worldwide renowned for its innovative power. In order to be one step ahead of the competition from other parts of the world, people are constantly looking for better efficiency in the use of raw materials and space. This, of course, without compromising the (top) quality of the Dutch product.

The glasshouse horticulture sector in the Netherlands can cope with this rapid pace of innovation thanks to a strong relationship between research and practice. In addition, a great deal of knowledge is exchanged between the entrepreneurs in order to make progress together. The flower auctions are a good example of this as one of the largest cooperatives in the world.
Below we describe a few examples of this innovative power.


Biological control and integrated pest management
In order to minimise the use of pesticides and to find a better balance between parasites and their natural enemies, natural enemies of the parasites are used in the greenhouses. Thanks to the intensive exchange of knowledge between the growers and their suppliers, growers are increasingly able to produce a top quality product with organic solutions.


Combined heat and power (CHP)
Combined heat and power (CHP) is a large engine, originating from the shipping industry. Only it has been converted to run on natural gas. The efficiency of this motor is higher than traditional gas boilers. These engines drive a generator that generates electricity. This electricity is used in the company’s own nursery or is supplied back to the public electricity grid. The ‘residual heat’ produced by the engine is used to heat the greenhouses. After cleaning, the exhaust gases can be used to provide the plants with CO2. All in all, these motors provide an efficiency that can be up to 20% higher than the traditional method of heating (gas boilers).


Geothermal energy
Geothermal energy is used for this type of energy. A drilling tower is used to drill a well to a depth of 2-3 km. At this depth, water of more than 80 degrees can be ‘collected’. This heat is used to heat the greenhouses and then the cooled water is returned to the soil via a second source. It is expected that these sources will be able to continue to produce sufficient heat, even longer than the life of a greenhouse.

Drilling the well is an enormously expensive investment. In addition, there is a great risk that the drilling will ‘fail’. By working together with each other and with governments, in the Netherlands we are able to gain experience with this way of heating greenhouses sustainably.


Water purification
Plants need water and nutrients to grow. More and more nurseries are making use of the reuse of drainage water. This is water that is collected before it disappears into the subsoil. This ‘drainage water’ still contains many nutrients that can be used by the plants.
By reusing this water and mixing it with clean water, less fertilizer is used.
However, the drainage water also contains some ‘wrong substances’. The content of these wrong substances determines how much water can be reused. The application of new techniques creates opportunities to filter these ‘wrong substances’ out of the water.


Diffuse glass
In new constructions, more and more growers are opting to cover their greenhouses with diffuse glass. Diffuse glass ensures that light is distributed much more evenly across the crop without any shade or light spots. This leads to a more even greenhouse climate.
Temperature and humidity can thus be controlled more accurately, which means, for example, that the opening of the air windows can be limited, which leads to lower CO2 emissions.


LED lighting in greenhouse horticulture
A new innovation in horticulture is the use of LED lighting. This lighting is not comparable with LED lighting used in consumer use. In the horticultural sector, the lighting is produced by ‘power LEDs’ and therefore much higher. The major advantage of these ‘power LEDs’ is related to sustainable business practices: energy savings compared to high-pressure sodium lamps (orange-coloured lighting). This saves more than half of the energy.
Another major advantage is that when using LEDs, crops can be better controlled using the different colours in the light. This is in favour of a better growth and a higher quality of the product.

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