Lawn & Garden

Make Your Own Compost Tea

Healthy soil is critical to healthy lawns.

And the healthiest soil is one with natural bacteria and organisms. Soil should be alive, with trillions of living organisms right under our feet! Many lawns and garden soils have lost this life, and as a result, we see dead grass, yellow leaves, and pests. The best, natural solution to fix your soil is to add compost tea.

Most of us have heard of compost – organic material used as fertilizer. Compost tea concentrates the healthy microorganisms and makes it easier for them to be added to soil. It’s the fast track to healthy soil!

Compost tea helps plants fight off pests and maintains healthy bacteria balances in your soil. Compost tea applies microorganisms directly to the leaves of the plants, where it can attack pests and form a protective layer of life. In the soil, the microorganisms gobble up decaying matter, make nutrients available for use by the plant, aerate the soil, and fight off pests.

The Recipe:

Here’s what you’ll need to make your own compost tea:
  • An air pump or aquarium pump (if using an aquarium pump, attach air tubes to put into the bucket and put the pump outside the bucket).
  • A 5 gallon bucket, ideally filled with rainwater
  • 3 cups of fresh compost or worm castings
  • A paint strainer or mesh bag
  • Molasses if you want more bacteria, steel cut oats if you need more fungi

Note: Compost tea that is extra heavy on bacteria is preferred for grasses, perennials, and gardens. Compost tea that is extra heavy on fungi is preferred for trees and shrubs.


  1. Fill a 5 gallon bucket with water, and let it sit overnight to get the chlorine out (or just use rainwater!).
  2. After airing out your water, add 3 cups of compost – put it in two tied up socks, or a compost bag, or loose (the paint strainer can be used to strain later if you don’t put it in bags).
  3. Attach your pump and start circulating air. Add a little molasses if you are brewing for a lawn, or steel cut oats for trees and shrubs.
  4. Leave in a place with a similar temperature to the outdoor air on an average day (not too hot!).
  5. Let it brew for 24 hours, or up to 48 hours if the temperatures are cool. It should look like dark tea, and smell earthy. If it smells foul or rotten, it’s been too long and won’t be any good.
  6. Filter if needed through the paint strainer (if you haven’t brewed it in bags).
  7. For lawns, dilute your tea about 50/50 with water (make sure the added water sat to get the chlorine out).
  8. Apply with a sprayer in the morning or evening – your 10 gallons of diluted compost tea will treat almost half an acre. For trees and shrubs, you can just drench the soil. On a rainy day is even better!

There are no financial incentives to help make compost tea.  But, the County does provide free yard trim compost bins to help make the compost.  Find out where to pick up your bin. 

When is the best time to spray my compost tea on a lawn?

The living organisms in compost tea are sensitive to UV light, so we recommend applying before 10am or after 4pm. Even better is to watch the weather, and brew your tea a day before it rains, and apply during the rain! (Hint—start your compost tea when you start your own dinner, and apply it after breakfast the next morning!)


Why do I need to spray this on my lawn? Can’t I just pour it out?

You could just dilute the tea and pour it on your lawn, but surprisingly, it helps to have the compost tea coat the leaves of the plant. You cannot tell it, but the compost tea sticks on leaf surfaces, where the microbes are very beneficial for controlling fungi and bacteria that might attack the leaves of plants.


What can I do with any leftover compost tea?

If you have extra, look for a nearby street tree to water it with. All our street trees would love a little bath with beneficial microbes.


How often should I apply compost tea?

While your plants are growing, you might want to consider applying every 14-30 days, especially if plants seems stressed.


I don’t have my own compost pile. Where can I get compost easily?

You only need 3 cups at a time, so consider buying a bag of compost or worm castings at your local garden store, or even online. Keep the bag well sealed so it won’t dry out, and use any extra in the fall around garden plants, trees, or spread thinly across a lawn.


Why can’t I just apply fertilizer? This seems like more work.

Fertilizers are just temporary fixes, like caffeine in the morning. The effects wear off, and the soil becomes less and less “alive” with fertilizers.

Soil micro-organisms are what make nutrients available at the right times for the plants. Using compost and compost tea, along with aerated soil (so the microbes have access to oxygen), will save you money and headache, and have lasting effects.


Does adding compost tea violate the Maryland State Fertilizer laws?

Compost tea and compost are very different. Compost tea will not have much phosphorous, as when we brew it, we are multiplying the microbes, not the nutrients, which are then highly diluted. Think about it—if the liquid from 3 cups of compost will cover half an acre, that’s a tiny fraction of how much compost would have to be spread across the same area!

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