News » 28.08.2025 - Bacillus as living insurance for the root zone
Microorganisms play a key role in crop performance. Increasingly, growers are using bacterial products, often based on Bacillus strains, to support their crops' resilience, root development and nutrient uptake.
"It's hard for people to grasp that bacteria can collaborate so effectively with plants, even though they have no consciousness, nervous system, or intent," says Marco Breekweg, a microbiologist with over thirty years of experience in horticulture. He notes a growing interest in root zone biology, especially as more growers transition to organic substrates.
"A bacterium literally has an IQ of zero. The interaction between plant and microorganism is the result of co-evolution—traits developed over time because they enhance the survival of both organisms. A bacterium that can release nutrients or produce growth hormones will benefit from doing so, as the plant responds by secreting more root exudates, which in turn provide more food for the bacterium. It's a relationship of mutual benefit, without conscious intent or planning."
Bacteria can become 'lazy'
A lesser-known but relevant phenomenon is that in rich environments, for example with abundant root exudates, bacteria start to specialise in what is most available there: for example, sugars. "This can cause other functions, such as producing enzymes or growth substances, to become less active," Marco knows.
"This effect is known as phenotypic plasticity: the ability of a bacterium to adapt its behaviour (gene expression) to conditions. Instead of investing energy in functions that do not directly contribute to growth at that moment, they temporarily switch to the most efficient survival strategy."
So this 'getting lazy' is not a genetic loss, he stresses, but a regulatory effect. "In monocultures or substrate crops with little microbial diversity, this behaviour can be more pronounced."
Maintaining functionality: regular replenishment
To keep the rhizosphere active and functional, Marco advises regularly supplementing with beneficial microbes. "Introducing fresh, biologically active microbial life helps maintain or restore balance in the root zone. This is especially important in closed cultivation systems, when reusing irrigation water, or in conditions with limited natural microbial diversity, like sterile substrates or systems where disinfection is frequently used."
Practical application for growers
A healthy, active microbial network in the root zone enhances nutrient uptake, promotes faster root development, increases resistance to root pathogens, and improves growth under stress conditions, such as drought or salt accumulation.
"Bacillus-based products are most effective when used preventively—ideally from the start of the cultivation cycle—so the beneficial microbes can colonise the rhizosphere before pathogens or stress factors appear," Marco advises. Biomicrobes offers several solutions for this purpose.
Balanced blend of good bacteria
Biomicrobes 08 is a product specially developed by Microbac to keep the root environment active and healthy. "It contains eight main types of beneficial bacteria that complement each other in their action. Together, they ensure better nutrient uptake, healthier roots and a stable microbial balance around the plant."
The following bacteria are contained in Biomicrobes 08:
Bacillus subtilis - Helps release nutrients and stimulates root growth
Bacillus licheniformis - Ensures stable bacterial activity and makes phosphate available
Priestia megaterium - Dissolves difficult to dissolve phosphate via natural acids
Bacillus pumilus - Facilitates absorption of iron and other trace elements
Bacillus amyloliquefaciens - Supports root growth and aids nutrient uptake
Bacillus laterosporus - Maintains microbial balance
Bacillus mucilaginosus - Releases potassium from soil particles
Paenibacillus polymyxa - Binds nitrogen from the air and stimulates root formation with natural growth substances
Bacillus as living insurance of the root zone
Still, Marco cautions that Bacillus products are not miracle solutions. "If a plant is already severely weakened by disease, poor soil structure, or exhausted substrate, the effectiveness of these microbes may be greatly reduced. In such conditions, the environment simply isn't suitable for strong colonization or microbial activity."
That's why preventive use is key, he emphasizes once more. "Bacillus functions like a living insurance policy for the plant—it stimulates, protects, and brings life to the root zone. When applied in time, it's ready to support the plant from the ground up."
"Treat microorganisms with care—they work tirelessly for the plant. They respond to signals, adapt to changing conditions, and strengthen crops in ways we often can't see. The future of sustainable cultivation lies not only above ground, but also in the vibrant, microbially active world beneath our feet."
Source: www.floraldialy.com
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