Home-Brew Probiotics

Many growers have realized the benefits of using beneficial microbes on their plants – faster, healthier growth with far fewer incidences of rot. Applying them regularly is not exorbitantly expensive – especially considering the investments we have in our plants – but it is a real cost.  Fortunately, it’s really not that difficult to “multiply” that purchased bottle of product into larger volumes of home-bre probiotics for use.  Here’s how:

Brewing your own probiotics is a fermentation process, just like beer or wine, so any local or online home brewing supplier will have the materials you will need. Specifically, you need an air-tight container with an airlock, or the ability to vent it daily. If you want to keep it really simple, a clean PETE soda bottle with a screw on top is fine, as they can handle pressure and are readily available.


  • Airtight plastic container or tank with screw-on lid.  The container should be about the volume of the blend being made to avoid extra air space.  I purchased a Speidel Fermenter (below), as it has an integral airlock and spigot.
  • Be prepared to either use or make an airlock (image below) or manually release the pressure periodically. Fermentation releases carbon dioxide as the sugars are consumed, so you may have to “burp” the container as much as several times a day – especially early in the process – if you don’t use an airlock.


  • Commercial probiotic of your choice.
  • Blackstrap molasses (other types of molasses or high-sugar content syrups can be used).
  • Fresh, clean water. Some say that tap water is fine, even if chlorinated, but I think it’s better to avoid chlorine, so suggest using distilled, RO or carbon-filtered water.
  • To really “supercharge” the formulation, KelpMax may also be added.  (Kelp extract is a raw material in the Inocucor charge.)

Proportions are not critical, but a reasonable target is to keep the raw material blend to about 1 part each probiotic, molasses, and KelpMax to about 15-20 parts water. This simple chart will help:

Home-Brew Probiotic Additions - Fill up with Water
Container size:1 Quart1 Gallon5 Gallons
Probiotic/Molasses/KelpMax (each):1.5 oz6 oz1 qt


  • Fill your container to about 75% capacity with room temperature-to-warm water.  If it’s about bathwater temperature or so, that accelerates the initial activation.
  • Add the other ingredients and mix it up.
  • Add enough additional water to nearly fill the container.
  • Close and tightly seal the container.  The use of an airlock (under $5) is preferred, as it will vent the gases without allowing air to enter.  Otherwise, you’ll need to “burp” the container periodically.
  • Keep at room temperature for about 5-6 days, then check the pH.  When it reaches about 3.5-3.6 (I just use pH strips to estimate, seeking the point when the color indicates below 4.), give it another 5-6 days of “brewing”.  When the pH is stable for a few days, it’s ready to use at the original dose.  Note that cooler temperatures will slow the process while warmer conditions will accelerate it.  (Alternately, without pH testing, give it about two weeks or so of room temperature fermentation before checking the scent.)

At that point, the brew will have a slight alcohol scent and may have some white particles floating on the surface, indicating it’s ready to use.

Your home-brew probiotics will be good for a couple of months, but be sure to set aside a full bottle of fresh material in the refrigerator for your next batch.

This YouTube video shows a similar process, using somewhat different proportions.

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