So our adventures in the world of compost are continuing, and we have begun experimenting with “Active Compost.” Previously, we explained the process and benefits of making and using passive tea–and have since been diluting it and using it in our garden beds.
To take our operation to the next level, we purchased a few supplies (and salvaged a few others) to begin the active tea brewing process. Here is our supply checklist:
- A vessel to hold the tea (we used an old garbage can)
- Garden compost
- Aquarium air pump (ours is rated for 60 gallons)
- Air tube for pump (10 – 15 feet is the absolute most you’ll need)
- Air stones (to diffuse oxygen, placed at end of air tubes)
- T shaped line splitter
- Sugary food scraps (think rotten banana, apple core)
The supplies we needed cost about $30 new at a local pet store, but you could also find them at a garage sale, thrift store, or in your basement/attic . . . just gotta look for them.
Once you have your materials together, find yourself a good spot to brew the tea. It won’t take too long

(3-5 days), but your pump will need to be running consistently throughout the brew process, so make sure you have a safe location to plug it in if you’re doing it outdoors. We have ours working in the basement, and there is little if any odor at all.
The active compost tea is similar to passive tea in that it is a method of pulling beneficial minerals, fungi, microorganisms, etc. from compost and into water so that it can be quickly applied to and absorbed into the soil and thus, the plants in our gardens. Active tea differs in the way the beneficial microbes grow, but it’s essentially the same science project (just done a bit faster, and with slightly better results, we’re hoping). How? Why? We’re using the aquarium pump and stones to aerate the water, and some sugar from food scraps to feed the microorganisms, so that they can grow and multiply quickly (via more oxygen and food).
The only setup is the air pump system, which is very simple. This includes the pump, tubes, and air stones. Carefully cut your tube so there is 3 feet or so running from your pump out to your tea vessel. Our pump has two connections, so we cut two 3 foot pieces to reach the can.
At the end of the tubes we attached a line splitter and cut two short pieces of tube to connect the diffusers (Air Stones). Upon completing our pump system, we have a pump, two tubes running out, a splitter on each tube, and an air stone after each split. The only thing left to do is add the water and compost, and the brewing can commence. Don’t forget some food for your microbes–if you have some partially decomposed food scraps in your pile that should

work, but if you want to be safe, add an apple core or two, or perhaps a rotten banana and its peel.
We used 3 parts water to 1 part compost. First we put in the water, then we added the compost, stirred with a shovel, and finally dropped the airstones into the bucket. Every day, pull out the tubes and give the bucket a good stir.
Give your active tea about 3 days to brew, and it should be ready. Unlike the passive tea, this method doesn’t use a bag to filter the compost, so it’ll need to be screened / decanted to separate the liquid from solid. And when applying to your garden, make sure to dilute to avoid potential burning on your plants. You won’t need much more than a few tablespoons per gallon of water (preferably rain water, as chlorine, etc. in municipal water will kill your precious little microbes).