Compost Tea Brewing

How to kill slugs

   What is Compost Tea
   How to apply Compost Tea

   Full list of compost tea products.


Compost Brewing Tea – How to
   How to Make Compost Tea – Brewing Instructions


What is
compost tea?

Compost tea is an aerobic water solution that has
extracted the microbe population from compost along with the
nutrients. In simple terms, it is a concentrated liquid
created by a process to increase the numbers of benefitcial
organisms as an organic approach to plant/soil care.

The concept behind compost tea is quite simple, though the actual process of making compost tea becomes scientific and very complex. The idea is that compost (full of beneficial microorganisms) is put into water and then nutrients or foods for the microorganisms is added to allow the bacteria and fungi to multiply rapidly. Air is sent through the water to keep the water oxygenated, as this favors the beneficial bacteria and fungi over the pathogens (ex.-e coli). At the end of the brewing cycle, what you have is a concentrated liquid full of billions of microorganisms (bacteria, fungi, protozoa, nematodes) that can then be sprayed directly onto the leaf surface. This puts the “good” biology where the plant needs it to protect itself. It keeps the plant healthier and helps it to fight off potential diseases. The “good” biology occupies the infection sites on the leaf surface and is held there by simple sugars that the plant puts out (exidates) that work as a glue to keep the beneficial microorganisms thriving and protecting the plant. Compost tea has been used by many people all over the world with mixed results. Part of the problem relating to studies on compost tea is that there is a high diversity in the quality of the compost tea produced in many of these studies. After all, if you don’t start with good compost, don’t add the proper amount of nutrients, or don’t keep the brew sufficiently aerated, you could be selecting for the “pathogens” rather than the “beneficials,” and end up with compost tea that could potentially harm your plants. Much more likely is that the compost tea would be low in bacteria and fungi and have little more effect than putting water on your plant. At Keep It Simple, we take great care in our tea production and have tested all of our products throughly every step of the way. Our recipes have taken years to develop and we worked to maximize the biodiversity of our final tea product.


How to Apply Compost Tea

After brewing the compost for 12 – 18 hours with the 5-gallon brewer or 24 hours for the larger brewers, the tea may be used as a foliar spray with a backpack sprayer on your plants or lawn. The backpack sprayer has a more useable nozzle that will not clog with the application. You may also apply with a watering can directly to the roots.

Application should be done in the morning or under cool conditions. It may be done in the rain when applied to the soil/lawn. When applied to leaves, it should be done during dry conditions. Because the microbes are active, they will attach themselves in 20 minutes. 

The compost tea is most effective when used within 4 hours after the brewing process is completed. When the machine is turned off, the microbe population starts decreasing and you will want to use the tea when it has the highest microbe count. Four hours is the maximum time delay before application.


How to make Compost tea.

Brewing Instructions for the KIS 5-gallon Brewer

Once the brewer is assembled, fill your bucket with water just shy of 5 gallons,
making sure the insert is in securely.

With dry hands, plug your motor in, put the lid on the bucket and start the

Run for approximately 20 minutes if you have chlorine in your water.

Drop the “tea bag” and contents of the plastic bag into the bucket, again
with the lid.

Brew for at least 12 hours before use.

You may brew up
to 20-24 hours, although as you approach 24 hours, you will
need to add more
food and compost.
Use within 4-6 hours from the time you stop the motor for optimum benefit.

Note: Make sure to clean your machine immediately. Run clean water
through with the pump running
and/or put the parts in the dishwasher to
eliminate the possibility of biofilm.

It is extremely difficult to get high fungal numbers in your compost tea. The most important variable is your compost. If you don’t put a high fungal biomass into your brewer at the start of your brew, there’s no way to get a high fungal count in your finished compost tea. Our fungal compost has extremely high levels of beneficial fungi (click here to see our lab results), and allows us to make a diverse, bacterial/fungal balanced tea with high nutrient cycling. Many commercial and homemade brewers make good bacterial teas, but without a good fungal compost, foods, and aeration, you’ll never get high numbers of beneficial fungi on to your plants and into your soil


Frequently Asked Questions

What is compost tea?

daylilyCompost tea is an aerobic water solution that has extracted the microbe population from compost along with the nutrients. In simple terms, it is a concentrated liquid created by a process to increase the numbers of beneficial organisms as an organic approach to plant/soil care.

Why use compost tea?

Compost tea has many benefits. It will make our environment healthier and safer and will put the microbe biology back onto the plants and soil. It recreates the natural environment that plants have evolved through millions of years to be healthy.

How long does it take to make compost tea in the Keep It Simple® 5-gallon brewer?

It takes 12 hours at 55°-80° or longer if the temperatures are colder. The warmer the temperature (not to exceed 95 degrees), the faster the brew (with a minimum of 12 hours).

How long does it take to make compost tea in the Keep It Simple® 5, 28, 55, & 100, 500, and 1000-gallon brewers?

It takes 24 hours at 55°-80° degrees or longer if the temperatures are colder in the larger brewers, 12-hours (or more) in the 5-gallon brewer.When do I apply compost tea?

The tea must be used within 4 hours after you have turned the motor off and it has finished brewing to achieve maximum benefit. The best time to apply in the day is early morning or early evening. Hot day time temperatures are not as effective and will reduce the good biology.

How often should I apply my compost tea?

For foliar disease prevention, you can spray the plants just before you would usually have the onset of disease occurring. Then you would spray every 10 days to 2 weeks for about a month. You should monitor what you are seeing on your plants to determine if further spray is needed. For soil application we recommend two times a year spring and fall. For promoting growth, you could spray once a month during the growing season. Frequency and scheduling of applications will vary depending on individual environmental conditions. You cannot over-apply compost tea.

How can I get more food brewing kits and how long will they keep?

You may order more kits from the person or nursery you purchased your brewer from or directly from us. The food brewing kits will keep for a year as long as they have been stored properly.

How can I get more food brewing kits and how long will they keep?

You may order more kits from the person or nursery you purchased your brewer from or directly from us. The food brewing kits will keep for a year as long as they have been stored properly.

How do I apply the compost tea to my plants and soil?

You can use a sprinkler can for applying to the soil or a backpack sprayer or a sprayer that has a nozzle that will not clog to do a foliar spray (see below). The backpack sprayers have a different type of nozzle that will not clog when applying compost tea. 

Can I spray compost tea through a hose canister sprayer?

Generally, no. If you have untreated water then you can. If there is chlorine in the water that will kill all the microbes.

What happens if the tea isn’t used within 4 hours?

The population of microbes decreases as the tea goes anaerobic and it becomes less effective.

What happens if the brewing process is interrupted?

It really depends on how long the process has been interrupted. Generally, you would just start the process again.

What happens if temperatures are too cold?

The air temperature determines the water temperature because the air is moving through the pump into the water. If the temperatures are too cold (below 70 degrees), it will take longer for the microbes to produce and you will need to run your brewer for a minimum of 3 hours longer. 

What time of year is best to use the compost tea?

During the growing season or anytime when night time temperatures are above 40 degrees.

How long do the microbes live after I apply them?

If the living conditions are right, the microbes will continue to live and reproduce.

Can I apply too much tea and do damage to my soil or plants?


Can it hurt my pets?


I have ordered your fungal compost in bulk and don’t know how to store it properly. How should I store the compost?
Click here to read our bulk compost care instructions.

Will the compost tea get rid of diseases on my plants?
Compost tea suppresses disease.

*Black spot
*Mildew (downy)
*Needle cast on pine
*Vertilcillium wilt
*White flies
*Mealy bugs
*Tent caterpillars
*Leaf curl
*Red thread (early and late)
*Fungal diseases in ornamental cherries

What happens if I put the teabag in and forgot to put the food in?

Then you need to add it and start your brewing process again.

Does it make a difference of what kind of water I use? (tap, bottled, pond, etc.)

Yes, it needs to be water that doesn’t have chemicals in it. If you are using treated water, you need to follow the instructions and run the brewer for 20 minutes before adding the compost and food. This will degas (remove the chlorine from) the water.

How do I take care of my machine?

Remove the coil from the bottom of the bucket and pull out the rubber stopper prior to turning the air pump off. This keeps the tea out of the pipes, so biofilm does not buildup. With biofilm buildup, the next time a brew is made, it would contaminate the integrity of the tea. Hose off the coil and plastic pipes or put them in the dishwasher. Pour the tea into a backpack sprayer or sprinkler can for application. Rinse the inside of the bucket and the lid. Let dry.

Can I use my own compost?

Yes, you can use your own compost, but because we haven’t test the quality of your compost, we don’t know the biology that you have. The machines replicate only the biology they start with which can be beneficial or not. We recommend having your compost tested before you use it in the KIS brewer.

If you want to know what you are spraying, continuous lab testing is essential. The lab results tell us many things:

1. the quality of the compost
2. the quality of the tea brewed (what is the actual count of the microorganisms)
3. the quality of the food source added (if it has grown the microbes within the necessary range)
4. the quality of the brewer that is doing the replicating

NOTE: The results of your lab tests may also be affected by the quality of your water source.

We have tested all of our foods and compost and done extensive testing in creating our Pro Kit. Here are some of the test results. The results are in pdf format.

5-gallon Brewing System with KIS Composts and Foods (pdf)

5-gallon Brewing System with KIS Composts and Foods (2) (pdf)

Fungal Compost (pdf)

We test the compost prior to putting it into teabags. There are many variables involved with each batch tested. The following test is the result of batch #4604 of the compost and the tea. Your brewed tea should be similar, though may vary with different temperatures and water use.

What do I do with all of the items contained in the bag for the food (for 5-gallon brewer)?

The compost is in the mesh bag, while the other ingredients are in plastic bags. Drop the mesh bag in the water after dechlorination. Then open the plastic bag and pour contents into the water solution.


I have purchased bulk compost and a mesh bag from you. How do I brew my tea?

Are your foods and compost organic?

Yes, they have been tested (see our lab results) and are completely natural. No human or animal wastes are used in the compost. Our compost is 1/2 vermicompost (worm poop) and 1/2 thermal heated garden wastes.

What are the benifits of Compost Tea?

  • Tea-applied microbes consume and out-compete pathogens for plant surfaces and food resources
  • Reduces application rates of chemical pesticides, herbicides, and fertilizers.
  • Increases the number of organisms on and around the plant to compete with disease-causing organisms.
  • Occupies the space around the infection sites so even if the disease-causing organisms do start to grow, they can’t penetrate into the tissues of the plant.
  • High nutritional value for plants and soil
  • Provides food to:
    • Feed beneficial organisms that protect plants (occupies infection sites)
    • Sustain and inoculate plants
    • Help extend root systems
    • Add nutrients (biology) to the soil
  • Increases water and nutrient retention
  • Increases microbial numbers and activities
  • Aids in the breakdown of toxins in the soil and on plants
  • Helps our watershed soil and water quality by improving soil structure, which in turn increases water infiltration/retention, oxygen diffusion, and microbial activity
  • Enhances organic taste of fruits and vegetables
  • Creates a safer place for people and animals by using a natural approach to plant and soil health rather than using chemicals
  • Impossible to over apply to plants and soil because it is completely natural and organic
  • Since you are able to spray the tea directly on the leaves of the plants, this puts the organisms directly on the plant as opposed to adding compost to the soil around the plant.
  • Portability-You can spray at a rate of approximately 5 gallons per acre, depending on the biological numbers of the your tea solution and 20 gallons per acre on soil drenches.



“The KIS brewers are extremely easy to set up and use, very easy to clean, and make great teas by extracting all the species of bacteria, fungi, protozoa, and nematodes present in the compost into the tea. Using the right resources, the KIS brewer can get fantastic fungal biomass growing in their tea maker. Using the KIS starter foods and compost, we have never seen the KIS brewer have a problem maintaining aeration. Even if “poor compost” has been used, where E.coli and other pathogens were in high numbers, these problem organisms have been dropped to less than detectable levels by the proper use of this machine.”

~Dr. Elaine Ingham, Soil Microbiologist, author the “The Compost Tea Brewing Manual, 5th ed.”
Corvallis, Oregon


“From the instant I got my KIS brewer, I knew it was going to be fun. The instructions were so simple that I set it up in about three minutes and turned it on before I went to bed. I used the tea in our greenhouse the very next morning (14 hours later instead of 12, but that was only because I slept in!). It was a fine looking brew with a great smell, good feel, and excellent color. I was quite sure my plants would appreciate it and I couldn’t wait until the snow melted and I could get our and use the KIS-made compost tea on our gardens and lawns.

Since that first day, I have made dozens of brews with the very same KIS brewer. And what a joy it is to use. The machine is so easy to assemble that I can decide to make tea one minute and be brewing it the next. And it is just as easy to disassemble for cleaning. The stopper is a real nice touch that allows the cleaning of the inside of the system. Cleaning the system takes me all of 30 seconds and that long only because I do such a good job.

Am I pleased with my KIS? Just try and take it away from me.

Thanks for this important machine. It will change the world. I know it has changed the way we garden here in Alaska.”

~Jeff Lowenfels of Garden Writers of America, author of “Teaming with Microbes, A Gardener’s Guide to the Soil Food Web.” Jeff is a member of the Garden Writers of America Hall of Fame, he is a leading proponent of gardening using the concepts of the soil food web. His life-long love of gardening has led him to writing countless articles, hosting a popular gardening television show, and founding a successful program for soup kitchens called “Plant a Row for the Hungry” that is active in 48 states and has resulted in over 14 million meals fed to those in need.


“This was the best garden I’ve have had in years! I really noticed a difference with the health and taste of my vegetables and I didn’t have any disease problems. I love the smell and my garden loves it too!”

~Carin N. , Home Gardener

Seattle, WA


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