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The 5 Most Popular Bacillus Strains and what you can do for your grow 

What Microorganisms To Use For Improved Health & Vigor in Plants
By Zac “The Grow Guy” Ricciardi

Experienced growers know that microorganisms contribute to stronger, healthier plants. 

Growers looking for ways to improve the overall health of their environment may find benefit in Bacillus, a genus of bacteria made up of 260+ species of microorganisms known to help with enzyme production, plant vigor, nutrient uptake, and pathogen resistance. 

Regardless of your grow style, utilizing bacillus in your space will improve the overall health of your environment. 

What is Bacillus? 

Bacillus is a genus of rod-shaped bacteria that has over 260 named species found all over the world. 

There are many documented benefits that bacillus can exhibit, not just in plants but in people too. These benefits include essential enzymatic production, improved vigor, better nutrient uptake, better disease resistance, and nitrate conversion. 

Bacillus has the added benefit of performing well in any substrate–containers, inert media, and native soils. 

1. Bacillus Subtilis (BS) - Root Zone IPM Tool 

BS is a spore that aids in enzymatic production (the production of necessary enzymes used by the plant). 

BS also aids in mineral solubilization (the dissolution of minerals into forms that can be readily uptaken) and nitrate reduction, which is important as minerals are broken down from their source materials. BS also assists in ammonia conversion, helping to reduce concentrations below toxic levels, and is known to dominate other less-desirable fungal and bacterial spores (I.e. pathogen sources). Additionally, Induced Systemic Response (ISR) from BS has been documented, further tying overall plant health to microbial activity. BS works best in root zone applications, but can be effective in both soil and canopy colonization. 

2. Bacillus Amyloliquefaciens (BA) - Canopy IPM Tool 

Similar to BS, BA is a great enzyme producer, as well as a powerful fungal and bacterial adversary. Like BS, ISR activity has been tied to this microorganism, helping plants grow more vigorously then they would otherwise. BA is commonly used for its IPM benefits in both canopy and root zones. Unlike BS, I have seen better dominance from this BA in the canopy as it is very hardy and can survive for much longer than other spores in the same environment. 

3. Bacillus Pumilus (BP) - Complimentary Microbe 

BP may be a lesser-known bacillus strain, but it’s the real workhouse when it comes to enzymatic production. BP works VERY well with BS and BA as a complementary microbe, helping with ammonia conversion as well as combating fungal and bacterial colonies in the rhizosphere. BP is a dominant microbe and does its best work colonizing in your rhizosphere. 

Quick Bacillus Tips: 

  • Utilizing a disinfectant before a bacillus application can offer superior colonization. 
  • Healthy tissue gives you a healthy start from the jump. 

4. Bacillus Lichenformis (BL) - Feeding Schedule Supplement Unlike the previous three strains, BL helps with plant nutrition and is an amazing addition to any feeding schedule. BL makes the most of your nitrogen and phosphorus inputs, making them very bioavailable. The heightened enzymatic production from BL can help prevent mineral lockout not related to pH. It also has some fungal and bacterial antagonization but is more suited towards maximizing your plant’s uptake. Due to its assistance with the uptake of nutrients in your medium, BL is most effective when applied to your rhizosphere and root zones. 

5. Bacillus Megaterium (BM) - Feeding Schedule Powerhouse Think of BM like steroids for your inputs; this microorganism is the powerhouse of chelation, maximizing any feeding program. Not only does BM have some of the highest levels of enzymatic production, but it also tolerates high-salinity environments, making it a great tool for preventing mineral buildup and lockout. This above-average ability to convert nitrogen allows BM to supplement any feeding schedule. While BM does have some fungal and bacterial control, it is better suited to nutrient maximization. 

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