Compost Tea

Compost Tea is a great way to keep your plants healthy! It’s been shown to help ward off disease, increase nutritional quality of vegetables, and makes your compost go further.

You can use it as a spray, or add it directly to the soil.

Supplies you will need


To brew compost tea, you’ll need a pump, some air tubing, a gang valve, and three bubblers.

• An aquarium pump large enough to run three bubblers or air stones

• Several feet of tubing

• A gang valve

• Three bubblers

• A stick to stir the mixture

• Unsulfured molasses (preferably organic)

• Something to strain the tea, like an old pillowcase, tea towel, or a nylon stocking

• A bucket

How to brew compost tea

To brew compost tea, you will need a 5-gallon plastic bucket and a few aquarium supplies: a pump large enough to run three bubblers (also called air stones), several feet of air tubing, a gang valve (which distributes the air coming from the pump to the tubes going to the bubblers), and three bubblers. You’ll also need a stick for stirring the mixture, some unsulfured molasses (preferably organic), and an old pillowcase, tea towel, or nylon stocking for straining the tea. An extra bucket comes in handy for decanting the tea.

Don’t try to make compost tea without the aeration equipment. If the tea is not aerated constantly, the organisms in it will quickly use up the oxygen, and the tea will start to stink and become anaerobic. An anaerobic tea can harm your plants.


1. Attach one end of a piece of tubing to the pump; the other end will connect to the gang valve.


2. Attach tubing to each of the three ports on the gang valve. Plug bubblers into the other ends.

Also, keep in mind that tea made using this bucket method needs to brew for two or three days and then be used immediately. If you work Monday through Friday, start the tea on Wednesday or Thursday, so it will be ready in time to apply it on the weekend.

If you’re on a well, you can use water straight from the spigot. But if you’re using city water, run the bubblers in it for about an hour first, to blow off any chlorine. Otherwise, the chlorine will kill all those beneficial organisms you’ve gone to the trouble of raising.

Once you have safe water, fill the empty bucket half full of compost. Don’t pack it in; the bubblers need loose compost to aerate properly. Cut a length of tubing and attach one end to the pump and the other to the gang valve. Cut three more lengths of tubing long enough to reach comfortably from the rim to the bottom of the bucket. Connect each one to a port on the gang valve and push a bubbler into the other end.

Hang the gang valve on the lip of the bucket and bury the bubblers at the bottom, under the compost. Fill the bucket to within 3 inches of the rim with water, and start the pump.


3. For adequate aeration, be sure the bubblers sit on the bottom of the bucket, which is half filled with compost.


4. Add water to within a couple of inches of the rim. If you’re using city water, aerate it first for an hour to get rid of any chlorine.

When it’s going, add 1 oz. of molasses, then stir vigorously with the stick. The molasses feeds the bacteria and gets the beneficial species growing really well. After stirring, you’ll need to rearrange the bubblers so they’re on the bottom and well spaced. Try to stir the tea at least a few times a day. A vigorous mixing with the stick shakes more organisms loose and into the tea. Every time you stir, be sure to reposition the bubblers.

After three days, turn off the pump and remove the equipment. If you leave the tea aerating longer than three days, you must add more molasses or the good organisms will start going to sleep because they don’t have enough food to stay active. Let the brew sit until the compost is pretty much settled out, 10 to 20 minutes, then strain it into the other bucket or directly into your sprayer.

You’ll have about 2 1/2 gallons of tea. If you want, this is the time to add foliar micronutrients, like kelp or rock dust. Use the tea right away, within the hour if possible. You can put the solids back on the compost pile or add them to the soil. There are plenty of good bacterial and fungal foods left in them.


5. To feed the microorganisms, add an ounce of unsulfured molasses (organic is best) to the bucket and stir.


6. Stir vigorously a few times daily to shake free as many organisms as possible and to increase aeration. Reposition the bubblers after stirring so they’re well spaced.


7. When the compost tea is finished brewing, in two or three days, strain it into another bucket–you’ll have about 2 1/2 gallons–and use it immediately. This demonstration has been provided by