Compost Tea has been used for a long time by biological gardeners. There has been no shortage of debate through the years as to whether it was truly effective, and there are still naysayers out there – even professional naysayers (academia). Thankfully, most of these folks are catching up with what gardeners have known for years, and we are glad to have them on board.
There are many recipes for Compost Tea, but each has basically the same components. It’s sort of like baking a basic butter cake, the difference comes in the “pinch of this, dash of that” that each baker uses. The differences in Compost Tea come from the experiences and opinions of the brewer.
Compost Tea was originally made by placing a cloth bag of compost (like an overgrown tea-bag) in a bucket of water and leaving it to steep for several days. The bag was removed and the “tea” was then diluted. poured into a watering can and used as a drench around the root zone of plants.
A Better Brew
While this is one way of introducing some beneficial components to the garden, research has shown that there is a way of making compost tea that will increase its effectiveness many times.
One of the most important reasons to use compost in the garden is to introduce and maintain the highest possible number of beneficial organisms. Compost Tea with high numbers of beneficial organisms has shown to be an effective foliar treatment as well as a soil drench.
These organisms are living creatures that need oxygen to live. Most of these organisms will die off within just a few hours of being deprived of an oxygen source. The stagnant steeping process of most Compost Tea recipes results in this die-off.
Researchers at Soil Food Web, Inc., as well as independent researchers, demonstrate a way to keep these organisms alive, and your Compost Tea at its highest potential of effectiveness.
You will need:
(2) 5-gallon buckets
2-1/2 gallons (by volume) good quality compost
Un-sulfured molasses (or horticultural molasses)
Aquarium pump or live bait pump**
Several feet of plastic tubing
1) Fill one of the buckets with water and let it sit overnight to allow the chlorine to evaporate. Chlorine is harmful to many beneficial organisms. If you want to expedite the process, the chlorine can be depleted in a matter of hours if you oxygenate it by running the pump in it. Many municipal water sources now use Chloramine instead of chlorine. Chloramine does not evaporate like chlorine does and it has some detrimental affects. Check your water report to see if Chloramine might be an issue for you. If it is, there are several ways to remove it and I recommend a web search to see which works best for you. An easy option is to use rainwater. Freshly collected is best.
2) Put 3 – 5 cups of the best quality compost you can find in the second bucket.
3) After the water has been allowed to de-chlorinate, add 1 oz. of molasses to the water and mix it well. Pour the water/molasses mixture over the compost up to about 3” from the rim of the bucket.
4) Attach the pump to the rim or handle of the bucket, and run the tubing deep down into the mixture. Turn the pump on and allow the mixture to oxygenate for 1 – 3 days.
Safety Notes: Be sure to read and follow all of the directions for the pump you have purchased, and observe all safety precautions. If the pump is NOT supposed to be in water, be sure to wire it firmly to the handle or rim so that it cannot be “bumped” into the water. If small children or pets are in the area, be sure to place the filled buckets in an area that is NOT accessible by the child or pet.
5) After the brewing is finished, remove the pump and strain the Compost Tea off into the empty bucket. You may use a fine sieve, several layers of cheesecloth, or a piece of old sheeting as a straining filter.
Use the left over solids in the compost pile, or slosh them directly into the garden. The Tea can be poured directly into a watering can or sprayer. You can use the finished Tea as a soil drench, as a foliar spray, or both.
The beneficial organisms will begin to die off quickly, so add another ounce of molasses if it will sit more than an hour or so before you use it. It is best used as soon as possible after brewing. Don’t try to store unused portions.
As for the “pinch of this, dash of that”, some things that can be added to Compost Tea are:
Just add them in the same proportion you would to the volume of liquid you are using. For example, if you end up with 2-gallons of finished Tea, and you usually use fish emulsion at a rate of 1-ounce per gallon of water, you would add 2-ounces (1/4 cup) of fish emulsion to your finished Tea before application.
**Aquarium pumps can be found at pet supply shops and some variety stores (Walmart, Target). Live bait pumps can be found at sporting goods stores (Academy, Bass Pro Shop) and some variety stores. Plastic tubing can be found where aquarium pumps are sold, sporting goods stores, and the plumbing section of any hardware or home improvement store.