Compost tea is liquid plant food. You soak compost in water. The water absorbs nutrients and beneficial microbes. You water your plants with it. They grow faster, resist disease better, and produce more flowers and fruit.
I started making compost tea three years ago. My tomatoes went from decent to amazing. The difference was clear within two weeks of the first application. Here is how to make and use compost tea.
What Is Compost Tea?
Compost tea is not the brown liquid that drains from your compost bin. That is leachate. It may contain harmful bacteria. Compost tea is intentionally brewed by soaking finished compost in water with aeration.
The brewing process multiplies beneficial microbes. One teaspoon of finished compost tea can contain billions of beneficial bacteria and fungi. You are essentially brewing a probiotic drink for your plants.
How to Make Compost Tea (Simple Method)
This is the basic method. It takes five minutes to set up and needs to brew for 24 to 48 hours.
What you need: A 5-gallon bucket. Finished compost. Water. A stir stick. Optional: an aquarium pump and air stone.
Step 1: Fill the bucket with water. If you use tap water, let it sit for 24 hours first to let chlorine evaporate. Chlorine kills the microbes you are trying to grow.
Step 2: Put one shovelful of finished compost in a mesh bag, old pillowcase, or nylon stocking. Tie it closed. This keeps solids out of the liquid.
Step 3: Hang the bag in the water like a giant tea bag. Suspend it from a stick across the top of the bucket.
Step 4: If you have an aquarium pump, drop the air stone in the bucket. The bubbles add oxygen that beneficial microbes need. This makes aerated compost tea which is more potent than non-aerated tea.
Step 5: Let it brew for 24 to 48 hours. Stir a few times if you are not using a pump. The tea is ready when it smells earthy and has a foamy layer on top. The foam means microbes are multiplying.
Step 6: Remove the compost bag. Use the tea within four hours. The microbes start dying without aeration. If it smells bad, dump it. Bad tea smells rotten. Good tea smells like a forest floor.
How to Use Compost Tea
Soil drench: Pour the tea directly onto the soil around plants. It feeds the roots and soil microbes. This is the most effective method. Use one to two cups per plant. Apply every two to four weeks during the growing season.
Foliar spray: Strain the tea through a fine mesh. Pour it into a sprayer. Spray the leaves of plants until they are wet. Do this in the early morning or evening. Sunlight kills the microbes. The leaves absorb nutrients directly through their pores.
Seed starting: Water seedlings with diluted compost tea. Mix one part tea with two parts water. The microbes protect seedlings from damping off disease.
Lawn application: Spray compost tea on your lawn with a hose-end sprayer. It adds beneficial microbes to the soil. This improves nutrient availability and reduces the need for fertilizer.
What Plants Benefit Most from Compost Tea
| Plant Type | Benefit | How Often |
|---|---|---|
| Tomatoes | Bigger fruit, fewer diseases | Every 2 weeks |
| Peppers | More flowers, more fruit | Every 2 weeks |
| Leafy greens | Faster growth, darker leaves | Every 3 weeks |
| Flowers | More blooms, longer blooming | Monthly |
| Houseplants | Greener, healthier growth | Monthly (diluted) |
Frequently Asked Questions
Is compost tea a fertilizer?
Compost tea is more of a soil probiotic than a fertilizer. It adds beneficial microbes that help plants access nutrients already in the soil. It contains some nutrients but not enough to replace fertilizer. Use it alongside your regular fertilizing schedule.
Can I make compost tea without a pump?
Yes. Stir the tea a few times per day instead. Non-aerated tea works but is less potent. Aerated tea with a pump produces ten to a hundred times more beneficial microbes.
How long does compost tea last?
Use compost tea within four hours of finishing the brew. The microbes start dying without oxygen. If you keep the pump running, it lasts up to 24 hours. Never store compost tea in a sealed container. It goes anaerobic and becomes harmful to plants.
