Compost Tea for Beginners

Courtesy of Elaine Ingham 

To get started:

(1) In a five gallon bucket

(2) Fill up about 3/4 full with water

(3) Put your aeration gear (e.g. NTS Double Outlet Aerator) in the bottom of the tank (you want to see a roiling bubbling action on the water surface)

(4) Aerate until the chlorine, or any other smell is gone (add a teaspoon of humic acid if the smell isn't going away pretty fast, as in 20 to 30 minutes)

(5) Add a teaspoon of fish hydrolysate, or humic acid to help feed fungi, possibly a little (maybe a teaspoon) oatmeal, corn gluten, and/or kelp. You can experiment with the foods, but typically you want to make sure you add foods to feed beneficial fungi. What is lacking in house plants, in the garden, and in office plants is that fungal biomass.  If you have ever used an inorganic fertilizer on those plants, or used a pesticide application, then the fungi suffered more than anything else, most likely. Therefore, what you need to fix is the lack of "good guy" fungi. Other foods you could think about:- citric acid, or ascorbic acid, especially if you have really ugly water, i.e. high salts or strong odors- oils which are typically fungal foods. Just make sure they have no preservatives which kill microorganisms.  - ground grain, especially grains with the seed coat included in the grinding. This would be "Whole Wheat" types of flours.- chitin, ground up insects (dry the insects first, then grind them up). The external skeleton of insects contains a great deal of chitin, which is a great fungal food to encourage the beneficial fungi. Just try to make sure you ARE NOT adding the internal digestive system of the insect along with the skeletons, because the internal contents of the insect grow way too many bacteria. I'm sure others could add to the list here, especially if they have experiences showing that these different foods grow fungi better than bacteria 

(6) Find a fairly fine mesh, but stiff fabric, laundry bag or paint strainer bag (e.g NTS Spear Kit) and put about 1 pound of compost in the bag. If the fabric is not stiff enough to prevent twisting and compaction of the compost while brewing (look in the brewer when the tea is brewing, and check the compost - is it tumbling and floating around, or is it in a lump at the bottom of the bag?), then put something in the bag to prevent it from being able to twist and compact. Some  people actually put another little length of small diameter pvc pipe with holes in it (about an inch apart, stoppers on open ends. Just make sure you clean that "bag-holder-opener" or small aerator after each brew). Mesh size on the bag needs to be a little smaller than the nozzle size on your sprayer. See below about sprayers. Some people choose to brew by putting the compost free in the water.  That works, EXCEPT you then have chunks in the tea which will clog the sprayer. If you put the tea in a watering can to apply, then don't worry, no bag for the compost is needed. But if you use a back-pack sprayer,  or a hand spritzer unit, you need to make sure the mesh of your compost  bag is smaller than your sprayer, so you don't clog your sprayer.  

DO NOT strain your tea, because the fungi (a huge part of the reason we make tea) will be lost on and in the stuff that stays behind on the strainer.  The only way to strain and not lose the fungi is to CONSTANTLY shake the strainer so the fungi are not passing through a layer of organic  matter, and thus being held in that layer instead of remaining in the water. 

 (7) Put the brewer in a place where it will experience the same temperatures as the plants you are going to put the tea on.  Typically, this means outside some place, or your gardening area, or your greenhouse, or the garage, or.......... just think about what you are trying to do, and make sure it matches. We want the same shifts in temperature to happen to the tea as will happen to your plants.  That means, organisms are growing and increasing in number at all those temperatures, so that you are growing the most effective set of protective organisms.

(8)  In order to make sure that just the best organisms are growing, you need to make sure the brew stays fully oxygenated, or aerobic, through the whole brew. If in doubt, reduce the amount of food you add. Use a half teaspoon of each added food instead of a teaspoon. It is better to add a little of a  number of foods than to add just one food. Smell is important here again. If you start to smell bad odors, the tea is bad, and has been bad, for some time.  The beneficial organisms you wanted are long gone.  Put a stinky tea on the compost pile, or put it on your weed patch. Be careful with it, as some less than desirable organisms may have been grown.

(9)  Aerate, allowing organisms to grow, for 24 hours if the temperature is around 70 to 72 F.  If cooler, then let the brewing go on a little longer, for example, 36 hours when brewing at 50 F.  If hotter, then brewing times can be reduced, to say 20 hours when the temperature is around 85 to 90 F. Again, a little testing might be a good idea here, if you know anyone with a microscope who can look at these things for you. A few qualitative samples sent to the closest SFI lab might be wise, just to check your first two or three brews. We try to keep the cost low on the sampling if you are doing only general information and you don't need to publish the data.

(10) At about 6 to 8 hours into the brewing, remove the compost bag. The organisms that can be extracted have been extracted, so reduce the oxygen demand in the brew and remove the compost bag. Add that compost residue back into your compost pile.

(11) Finish the brew cycle.  Pour the tea out BEFORE turning off the aeration, so you don't get tea inside your aerators.

(12)  Look at the tea brewer insides as you drain the tea, or pour the tea, out. Any "stuff" left behind?  Could you rinse the insides out (swirl the tea as it goes out, splash the tea around a bit to rinse residues off the side of the brewer)? If there is still oil on the water surface, you are adding too much food for the organisms, and consider reducing the amount of fish oil, or hydrolysate. If the tea has the odor of one of the foods you added, the organisms aren't using up that food during the tea brew.  Either you want to activate the organisms in the compost more, so they will use up all the food, or you want to reduce the amount of food you add.

(13)  Put the tea in your sprayer. Spray. You only have a few hours before the organisms growing in that tea will use up all the oxygen and start some really un-pleasant processes that make wastes that you don't want to put on your plants.  Tea is a "make it, and use it", sort of process, unless you can put aerators into the sprayer tank. If you maintain aeration, then the tea can stay fine for 3 to 4 days more.

(14)  Make sure you cover as much of the top AND BOTTOM of the leaf surfaces when you apply compost tea.

(15)  If you are applying to the soil, there is no need to BREW.  Just use your tea brewer to extract the organisms, and apply straight to the soil.

Please consider a little consulting time with the folks at SFI if you have more questions.  Look at the phone number of the lab closest to you, and e-mail to set up a consulting phone call to answer any more of your questions.