By Veronica Castillo

The term “microbial life” encompasses all the tiny living things that one can barely see, if at all, on the ocean floor, rocks, and even on and in the human body. In plants, microbial life exists beneath the surface, feeding the plants through the roots.

Feeding the soil is just as important as feeding the plants. That’s where compost teas help. Compost tea is a blend of organic matter, a liquid created by extracting microorganisms such as bacteria, fungi, protozoa, nematodes, and micro-arthropods to create a tea for the plants.

Here are some of the things it does:

  • Improves soil health
  • Improves water retention, reducing the need for watering
  • Loosens clay soils
  • Protects plants from diseases
  • Combats the negative impacts of chemical-based pesticides, herbicides, and fertilizers

To get more information on this topic, I sat down with Benjamin Webb (benjamin-webb. Benjamin is a cannabis cultivator and consultant with 20+ years of cultivation experience in North and South America. He consults across the globe offering his expertise in cultivation, compliance, operations, protocols, and more. He has worked as a site director, regional cultivation director, and project management consultant, and continues to help the industry collaborate, solve problems, and grow.

Usually when something dies, there is no coming back in the physical, but it seems that dead soil can come back to life. Can you explain?

Soil is the best example of rebirth. In nature we have a continuous addition of organic matter back into the soil web from decomposing material, introducing microbes that once lived on and inside the plants’ leaves and biomass, as well as the nutrients therein, back into the soil. Compost tea is like a supercharged way of adding your beneficial bacterial and fungal microbiology back into your soil and plants. These microbes are responsible for an amazing array of processes that we call soil regeneration or soil restoration!

Are compost teas beneficial for indoor, outdoor, or both?

Compost teas are one of the most beneficial things you can give to your plants, both indoors and outdoors. For outdoor production, you will be amazed at the effects of Increased disease resistance and heat tolerance. You will see that the beneficial microorganisms in compost tea can also act as a deterrent for pests and reduce the need for chemical pesticides. Outdoors, depending on a few factors, compost tea could very easily increase nutrient mobilization inside the plant, protect the plant from pests both internally and externally, and increase yields and immune responses. This is not difficult to apply at scale.

For over a year I consulted with a farm that brewed 5,000 gallons of compost tea 24/7, 365. I have also personally kept and applied 50 gallons of compost tea per day for the better part of a year inside greenhouse production in Colorado. It’s not difficult to get into a real quality rotation with your teas to hit your desired application rates.

The stimulating effect that compost tea will have on your plants is noticeable to the naked eye. You can actually see the effects within a couple of hours, which in turn provides the impetus to continue to apply more compost tea. It’s a very rewarding experience. I have done this at scale with over three acres of cannabis canopy and I have done this just for fun in my backyard. Be careful, compost tea is very addictive!

Benjamin Webb

Do compost tea recipes exist?

Yes, there are a variety of compost tea recipes. One of the industry’s favorites is Dr. Elaine Ingham’s compost tea method called the Ingham Method. It really depends on the kind of tea that you are wanting to brew. Things change as you’re making a bacterial tea, or a fungal tea, or a biodynamic compost tea.

All compost teas have some things in common: your baseline organic input, which determines a lot about the effect of your tea; sugars and proteins, which are the food for the microbes; and some form of rock dust, which is where the microbes will do their multiplying. You add oxygen into this mix and you have the perfect environment to grow microbiology! As long as you are starting off with quality inputs with regards to your organic materials, and you organize your inputs to your needs/climate/environment, you should be well on your way to some amazing compost tea!

Are there different tea recipes for different regions or climates?

Absolutely, there are a wide array of different recipes for different regions, climates, soil types, and plant species. That’s not to mention biodynamic compost tea, which takes things a bit toward the metaphysical side of gardening/farming because of the connection with the moon cycles and so forth. But, as you can see, it can get complicated.

If I was formulating a compost tea for an outdoor location on the West Coast, I would make sure that certain microorganisms were in my base level organic material so that they would multiply in my tea. Considering the primary issues in West Coast outdoor gardens are spider mites, aphids, and powdery mildew, I would be making sure that Bacillus subtilis, Trichoderma harzianum, and Trichoderma koningii were all present in my brew. These all have such strong preventative abilities but they can also curb and eliminate a current or ongoing problem.

If formulating a tea for an indoor environment, I would help mobilize nutrition in the root zone. There, my focus would be on switching between bacterial-dominated and fungal-dominated compost teas to get the most out of each side while supplementing fulvic and humic acids for a super charge. Again, the effects of this are addictive, to your eyes and to the plants themselves, so apply compost tea carefully. Just FYI, with indoors, the foliar feeding of compost tea is not really done due to the clean room nature of an indoor grow. Most compost tea sees most of its action indoors with root zone applications.


What are some experiences you had that have shown you the power of continuous application?

I would have to take it back to 2016. I was running a medium scale farm. We had four 35×90-foot-long greenhouses. It was right under 10,000 square feet of canopy. In three of these greenhouses we had spider mites. We were using a mixture of canola oil and sodium laurel sulfate and were getting by alright. Around that time, a larger farm I was consulting with brought Dr. Ingham to their facility for a three-day workshop on compost tea, which I helped facilitate.

I was so inspired by what I learned that right away I started compost tea application in the three greenhouses that I had the spider mites. I applied the Ingham Method with a couple of personal changes every day for about three months.

What amazed me was that after about a month, you could still see the old damage but the new foliage was just brilliantly happy and pest free. It was gradual, but within six weeks, I noticed no damage on new growth at all and shortly after that, our spider mite issue was gone and it did not come back.

What are three things cultivators should immediately learn about mycology?

Learn your bacteria and your fungus! Learn their names, functions, and organic inputs. Ask: “What organic inputs will contain the natural bacterial and fungal microbes that I want to multiply and breed in my compost tea brew to fix or elevate my plant health, and/or assist with certain disease or pest pressures?”

Study the effect of mycorrhiza of the ribosome, which can enhance nutrient and water uptake. It’s important that we consider the overall composition of the soil food web and the microorganisms that keep that food web healthy and alive. We want to ensure that we not only feed the good bacteria but also the good fungals in our soil and that is done in different ways. This diversity ensures the replenishment and addition of the microbiology that enhances all of our other processes on botha fungal and a bacterial level.

Learn to grow your own fungal-dominated humus to add to your compost tea. Fungal microorganisms do not multiply in compost tea, they only get stronger. Once you learn to multiply those yourself and then add them into your teas, your plants are going to go into overdrive mode. The key is to do your homework, use compost tea for everything, and welcome to the wonderful world of microbiology!