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Hydroponics and Solugen – An interesting synergy

Hydroponics ?

Hydroponics is a growing method that does not require soil. Various materials are used, for example, mineral wool to replace the soil substrate, and the crops are grown in nutrient-rich water. Although there are many ways to practice hydroponics, the basis is the same; the plant draws its needs from a nutrient solution in which it is grown.

Hydroponics should not be confused with aquaponics, which also allows for soil-less cultivation, but in water supplied with natural fertilizers from organic waste and fish excrement raised in aquaculture. Aquaponics is a mixed system that combines aquaculture with plant culture in the same infrastructure.

The basis of hydroponics, as its name indicates, is the use of fresh water, filtered, of good quality with an ideal pH between 6 and 6.5, therefore slightly acid, well oxygenated. Plants need a root support to develop. Various solutions are used such as coconut fibre, mineral wool or vermiculite. Other important elements are of course the nutrients, in solution in the culture water and the light, in particular of the growth lamps.

The limits of conventional agriculture

Conventional agriculture, and more particularly its intensive form as practiced in many countries, although it allows for mass production, it does create various constraints and problems that are likely to intensify with the galloping growth of the human population. Indeed, with this demography, which is heading towards some nine to 10 billion human beings in 2050, it will be necessary to produce more and more to feed this population.

In this perspective, it will be necessary to optimize this agricultural production by a significant use of chemical fertilizers and pesticides, and to increase the arable surfaces by, among other things, deforestation, which adds a pernicious element to the effects of global warming, reducing the evapotranspiration from plants and the CO2 cycle. We should also note the progression of deserts and the scarcity of water, an economic and strategic issue in many regions of the world.  Projections show that by 2050, nearly 600 million hectares of land will have to be converted into cultivable land to meet the above-mentioned food needs. Furthermore, we have mentioned in previous blog articles that the progressive depletion of phosphate rock deposits is added to these problems.

Why hydroponics?

Of course, hydroponics is not the ultimate solution to all the problems mentioned above and in the short term will not be able to feed the entire human population, but it offers a synergy of very interesting advantages.


Hydroponics in greenhouses allows cultivation anywhere, including in suburban areas, and therefore promotes a local economy, a culture of proximity, limits the transportation of these plant productions (especially vegetables), and therefore reduces the carbon footprint resulting from their production, and guarantees a better freshness of products.

Example of hydroponic cultivation in vertical mode


Hydroponics also allows you to grow at any time of the year in a controlled atmosphere and light conditions, and to avoid climatic constraints (drought, frost, hail).

Higher yields

Plants raised in hydroponic environment are permanently immersed in the nutritive solution and under ideal conditions of temperature, hygrometry and luminosity. Their root network is not forced to develop as in the case of soil cultures to get the required nutrients, the plant grows faster and develops in height, generating higher yields, all things considered, than on a conventional substrate.

Optimized water management

Under optimal hydroponic growing conditions, water requirements are less than in traditional growing. Indeed, the water circulating in a closed circuit can be filtered and reused, and the controlled atmosphere allows an optimal management of evaporation.

Aquatic plants hydroponic cultivation in controlled environment in the Netherlands

Optimized management of parameters

Greenhouse cultivation, whether hydroponic or traditional, offers the advantage of being able to control and adjust the environmental parameters of cultivation to the needs of the client for optimal production, in terms of quality, yield and production time.

  • Control of the temperature
  • Control of the composition of the nutritive solution
  • Control of the light intensity, the type of lighting and the exposure time
  • Control of hygrometry
  • Control of the pH of the nutritive solution

Less pesticides, pest control

Since the plants are raised in a nutrient solution and not in soil and in a controlled atmosphere, the result is an optimal control of the proliferation of insect pests and therefore a greatly reduced use of pesticides, or even none in the case of organic crops, which in some cases have recourse to biological control, by introducing predatory species that attack the pests and not the crops, such as syrphid flies, a type of fly whose larvae consume aphids.

The nutrient solution

This is the cornerstone of hydroponics

To be “complete”, a hydroponic nutrient must contain the essential elements for plant growth. The concentration of this or that element obviously varies with the type of crop and the specific needs of the plant.

Main macro-elements

  • Nitrogen (N)
  • Potassium (K)
  • Phosphorus (P)

Secondary macro elements

  • Calcium (Ca)
  • Magnesium (Mg)
  • Sulfur (S)

Trace elements

  • Iron (Fe)
  • Manganese (Mn)
  • Copper (Cu)
  • Zinc (Zn)
  • Molybdate (Mo)
  • Boron (B)
  • Chlorine (Cl)

At the Harrow Research and Development Centre in Harrow, Ontario, researchers have created a patented computer program called “Harrow Fertigation Manager” that regulates nutrient inputs to greenhouse crops. The Harrow Research and Development Centre is recognized as the largest greenhouse vegetable research center in North America.

Solugen and hydroponics

Nitrogen is a crucial element for plants. Nitrogen contained in manure exists in two forms: ammoniacal nitrogen and organic nitrogen. Ammoniacal nitrogen is immediately available to crops if it is not lost through volatilization or leaching after nitrification.

Solugen’s slurry treatment technology allows the dissociation of the constituent elements of the slurry.

If we take the example of a maternity manure, we obtain after treatment

  • 84% of the treated volume in the form of pure reusable water. (*)
  • 10 % of the treated volume in solid form (about 30 % of dry matter) rich in phosphorus (85 % of the phosphorus contained in the treated manure)
  • 5% of the treated volume in the form of a liquid potassium concentrate
  • 5 % of the treated volume as ammonia solution

(*) the percentages may be subject to some variations.

This liquid ammonia form is more stable than ammonia gas in terms of volatilization and constitutes a first choice nitrogen fertilizer, easy to use in hydroponics and to dose according to the concentration level of the solution.

This ammonia solution has been tested by a Canadian agricultural research center which concluded, in general, that :

– No problems have been observed with the use of the product in irrigation

– Ammoniacal nitrogen is in soluble form

– The solution must be used in diluted form (3 to 300 ml in 1 liter of water)

– Can be applied by soil injection, drip irrigation or hydroponics

– Frequent application at low rate is preferable to occasional application at high rate

– The use of this product should be adjusted according to a specific fertilization program for each crop.

Test of Solugen’s ammonical fertilizing solution on cucumbers and tomatoes


Thus, a great opportunity for a fruitful  synergy between  Solugen’s fertilizing solution and hydroponics, all in a circular economy context.









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