Compost tea is like gold to the organic gardener. It is not only cheap and easy to make, it provides plants with a hearty dose of healthy nutrients immediately, which helps them to grow better and stronger. Unlike using compost in the soil, which slowly releases the nutrients , compost tea immediately provides the plant with nutrients, as the liquid is soaked up instantly by the roots.
TIP: Our expert gardening adviser, Rachel Klein adds, "Many in the soil repair business treat their gardens with compost tea monthly, on soils that require extra assistance. If normal composting is not adding enough nutrients into your garden's depleted soil, compost tea is a great long term solution."
Fortunately, compost tea is very easy to "brew," whether you are a beginner gardener or more advanced. It also requires very few tools to make.
The larger your container, the more tea you can make. If you have a very large garden, a large 55 gallon drum may be more efficient for you to produce the amount of tea you need. If you have a small garden, a 5 gallon bucket may suffice, which is about the minimum you should make.
TIP: Rachel says, "Our objective is to make an aerobic tea (one made with air) as opposed to an anaerobic tea (one made without air). Using an aquarium pump to pump oxygen into your tea as it "steeps" is extremely important. The purpose of the tea is to cultivate all of the helpful bacteria and fungus in your compost. Without air, these microorganisms will simply die and your tea will not be effective."
Time Needed: About three days- One hour to make, three days to soak, and one hour to apply
Step 1 - Set Up Your Pump
There are different types of aquarium pumps that would be effective for this project. The simplest one you can find in your aquarium shop will suffice. First, attach your tubing to the pump. Aquarium tubing may be too narrow and produce bubbles that are too small. In this case, use garden hosing and a clamp. Make sure to affix the tubing securely to the pump, so no air escapes. Do not use an aquarium stone to break up the bubbles. We want big boisterous bubbles.
Affix the tubing to the sides of the container with clamps or suctions, or bury the end of the tube under the compost in the bottom of your container.
Step 2 - Add Your Ingredients
Place your compost materials in the container. You want to have a good ratio of carbon and nitrogen based compost, just as you would in a compost pile. Do not pack the compost into the bucket, rather fill it loosely with the material so that it can be easily stirred. Don't fill the container with compost all the way. About 3/4 of the bucket will do.
Add water to the compost. If you can use rainwater, it will be healthier than tap water, which usually contains chemicals such as chlorine. Fill the bucket with the water, leaving enough space at the top so that when you stir the water, it does not spill over the sides.
TIP: Rachel suggests, "If rainwater is not an option, either let your tap water sit out for 24 hours (with the bubbler running), or visit an aquarium shop and purchase water treatment tabs to eliminate the chlorine."
Step 3 - Turn It On
Set your pump to medium and turn it on. After a few moments, it should look like the mixture is boiling. If not, adjust the pump higher or lower.
Step 4 - "Feed" the Tea
Once your system is going smoothly, add 1 oz of molasses and mix vigorously with a stick. The molasses feeds the bacteria and gets the helpful species growing really well. Reposition the bubbler at the bottom of your container after stirring.
Step 5 - Steep the Tea
Let your compost tea "steep" for 2 to 3 days, stirring the water every day. Reposition your tubing after each stirring. You can certainly stir more than once per day, but it will not necessarily make your brew any more nutrient rich.
Keep the bucket in an area where it will remain warm, but avoid placing it in the direct sun. Too much sun will promote algae growth, which will throw off the carbon and nitrogen balance.
Step 6 - Strain the Liquid
After 2 or 3 days have passed, remove your equipment from the container and strain the compost particles from the liquid. The easiest way to do this is to give the mixture 10 to 20 minutes to settle so that all of the large particles gather on the bottom. Next, securely attach a screen to the top of another 5 gallon bucket. Using a smaller bucket or container, scoop the compost tea out of the original bucket, and pour it through the screen to strain the water. This will help to remove all small particles from the mixture, so it easily be used in a sprayer if you desire.
Step 7 - Apply to Garden
Do not spray the concentrated compost tea directly on your plants, as it may burn them, especially if your tea is strong in nitrogen. Instead, dilute the tea with a ratio of approximately 1 part compost tea to 10 parts water. Again, rainwater will work best for this.
TIP: Rachel adds, "It is important to use your tea immediately. Without the oxygen flow, the microorganisms and fungi will begin to go to sleep."
Using a sprayer or watering can, apply the diluted tea to the roots of the plant, or the leaves if it is early morning or evening. Apply as needed, a couple times per month. Since it is a liquid, it will wash out into the soil quickly.
TIP: Rachel cautions you, "Do NOT use a sprayer that has been used for chemical sprays! Even if you rinse it out, leftover residues will kill the beneficial microbes in your tea."
The strained material can go back into your compost pile. However, if planning to make more tea right away, use a new batch of compost first, as the ingredients you just used will now be lacking in essential nutrients.
Let you garden enjoy the fresh jolt of compost tea! It's nature's best liquid fertilizer.