Marginpar's Journey to Sustainability - Part 2

Support the biological life in the soil.

By: RONALD BOSCH | 22-11-2023 | 4 min read
How It Works Sustainability
Marginpar farm

Around two years ago, I started to work as an agronomist with the Marginpar group in Kenya. After a proper introduction and visiting all the farms, it became clear to me that the production of quality summer flowers still depended heavily on chemicals. That had to change. Together with the directors, it was decided to develop a five-year strategic plan for agronomy. The primary target was reducing chemical inputs and introducing a more sustainable summer flower production method.

In a series of blogs, of which this is the second one, I’ll present the results of implementing a so-called Farm Manual with a different topic such as soil-borne pathogens, and crop protection.

Supporting the Biological Life in the Soil

Did you check my first blog about management of the soil-borne pathogen? In this second part, the story continues. It is about supporting the biological life in the soil.


Marginpar team Astilbe on Thursd
Marginpar astilbe team


Survive, Flourish, and Multiply

After the application of the different micro-organisms and organic products to the soil, it is important to create an environment where the micro-organisms can survive, flourish, and multiply.

There are a number of activities that can be done to support the micro-organisms in the soil before and during the cultivation of the crop:

Field Trials

Normally different products can be applied together without having a negative impact on each other’s establishment and development. This is not always the case, make sure the products are applied in the correct sequence and that different products do not interfere. This can be determined by implementing field trials with different products, with different combinations, and during different stages of the development of the crop. Do not forget the control group, a few beds with no additives at all, just fertigation.

Balancing Water and Nutrients With Fertigation

Fertigation is used to supply the crop with the correct amount of water and nutrients. The amount of water supplied can have an impact on the micro-organisms in the soil, when too much or too little water is applied the micro-organisms cannot survive and their numbers will decrease. The benefits will not be noticed.

The level of applied nutrients (fertilization) is expressed as E.C. (electrical conductivity [dS/m]) and when the E.C. is too high it might have a negative impact on the micro-organisms and other bio-life in the soil. The Marginpar farms are now adjusting the E.C. values to assist the micro-organisms and bio-life in the soil.

Boosting Fertigation With Organic and Controlled-Release Fertilizers

A second step in fertigation is the introduction of organic fertilizers and Controlled-Release Fertilizers. Marginpar has just started this journey in the Kenyan farms, and the Ethiopian farms have already more experience with this. We believe that the micro-organisms and other soil bio-life can develop better under this fertigation regime.


Astilbe field from Marginpar
Astilbe Vision Inferno


Some Additional Points

Now, I would like to continue with some additional points that are mentioned which are used in the Marginpar farms.

Organic Solutions for Soil Pathogens and Microbes

No fungicides are used when plants start to develop symptoms caused by soil-pathogenic fungi and bacteria. On-the-spot treatment with an organic product (repeat several times) and directly afterward add the micro-organisms to the soil to re-populate the soil with beneficial micro-organisms at the treated spot again.

Microbial Support Through Compost Integration

Compost is added during bedmaking; therefore, it is distributed equally throughout the bed. Once in the bed, the compost can support the microorganisms present in the bed. Additional compost can be added to the bed during the growing season or after the cutback of the crop when the compost is sieved and very small, it will be transported into the bed via irrigation or rain.

Biochar: Nurturing Soil Microorganisms

Recently the Marginpar farms started producing biochar. Biochar can be added while making the bed. It will be transported into the bed via irrigation or rain. It has been noted that biochar has a positive impact on the activity of microorganisms in the soil. The biochar provides mineral nutrients, carbon, and habitat (surface colonization).

Vermiculture and Vermiwash: Nutrient-Rich Boost

The Marginpar farms have also embraced the vermiculture process. Currently, the farms are focussing on ‘vermiwash’, which is a liquid filtered from the watery wash from the earthworms in the buckets. This suspension of nutrients and organic compounds is diluted and added to the beds. The results have been remarkable when the crop responded very well after the application. It also contains food for the micro-organisms in the soil.

Cover Crops and Reduced Tillage: Early Insights

Recently, the Marginpar farms embarked on the ‘cover crop’ journey and the first results have already become visible in two farms where earthworms have been found after the cover crop (after cutting) was placed on the soil. Under the leaves, a wide variety of insects, mites, and spiders were found. More results will be collected in the coming months. Next to the introduction of cover crops, on a few Marginpar farms, the tillage of the soil is reduced.


Marginpar worker with Pink Astilbe



Read more in my third blog Planting Material, an Accelerated Start!

Want to know more about my job at Marginpar? Read this article about me called 'Cultivating Nature's Marvels'.

Ronald Bosch profile picture
Ronald Bosch

Ronald A. Bosch is passionately dedicated to sustainable flower cultivation. With a background in tropical agriculture and a specialization in tropical phytopathology from the Dutch Wageningen Agricultural University, Ronald's journey into the world of blooms has taken him across continents, nurturing his expertise and love for the floral kingdom.

Ronald's career has blossomed from the Caribbean to Latin America and South America, finally finding its roots in Africa. In 2021, Ronald joined the Marginpar family, driven by the goal of enhancing the sustainability of their flower production. Flower brand Marginpar, a proud member of the FSI, has set its sights on achieving 100% sustainable flower production, and Ronald is at the helm of this green mission as their agronomist and phytopathologist.

But what does that mean, you ask? Ronald is no ordinary flower aficionado; he's a master of plant pathology, an interdisciplinary field encompassing botany, microbiology, crop science, soil science, ecology, genetics, biochemistry, molecular biology, and physiology. Agronomists like Ronald conduct intricate experiments to unearth the best practices for elevating crop quality and production. With a profound knowledge of chemistry, biology, economics, earth science, ecology, and genetics, agronomists can be aptly described as "crop doctors," committed to ensuring the well-being of the Earth's harvests.

In the world of sustainable cultivation, soil is the foundation, and it's where Ronald's quest begins. Ronald's burning question revolves around sustainable soil management. This is a challenging journey, especially in the realm of summer flowers, where research has predominantly revolved around crops like roses, often conducted by rose companies themselves. Ronald and his team are determined to chart new territories in understanding the limits and potential of their own precious blooms.

So, if you're curious to learn more about Marginpar's journey towards sustainability, be sure to follow Ronald’s blogs.



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