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Potting Mix Problems 

This is a transcript of a recent email conversation (19th November 2006) with Elaine Ingham (president, Soil Foodweb Institute) regarding why potting soil becomes poorly drained and why synthetic fertilisers seem to work better.

Stephen: Can you offer me some suggestions on how to keep my potting soil from being turned into compost by microorganisms? It seems after a few months the potting soil begins to drain poorly and the plants get water-logged.

Also, most of my plants in containers don't seem to grow as fast with organic fertilisers as with synthetic types. Any suggestion on how to make the organic fertilisers work better, without breaking down my potting soil. Thanks.

Elaine: What you are really telling me here is that you are water-logging the potting mix and it is becoming anaerobic.

Aerobic decomposition will result in improvement in air passageways, hallways, and pore structure in the soil. This structure is built by good, aerobic organisms.

But, if the plant pots are allowed to get water-logged, if the potting mix is compacted, then the beneficial organisms will be lost, and the plant diseases will be able to gain an upper hand.

Organic fertilisers don't work well without the proper set of organisms in the potting mix.

To maintain the right set of aerobic organisms, you may have to initially inoculate the potting mix with the right set of organisms, and make sure you don't over-water.

If you have any soil microbe questions either contact me , or email This e-mail address is being protected from spambots. You need JavaScript enabled to view it

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.

Ridding Water of Mosquitoes 

Courtesy of Elaine Ingham

Protozoa eat the young larval stages of the mosquito.

In good water with lots of air, the protozoa best at eating all that zooplankton type of life are the flagellates and amoebae, along with a few ciliates. When water gets stagnant, the flagellates and amoebae diminish in numbers and activity.  Only ciliates are left, but when the water gets really bad, not even the ciliates are left, and that is when mosquitos get to be really bad. 

Fish fry - the youngest stages of fish after they just hatch - are also really good at eating mosquito larvae, and eggs too.  But again, if water is stagnant and putrid, i.e. anaerobic, then these biological control measures are non-existent as well. 

Algal blooms are significant players in this, and work by Steve Carpenter at the Univ. of Wisconsin showed, back some 15 or 20 years ago, that algal blooms are the result of losing the zooplankton, which of course, includes both the groups I was pointing out above.  The zooplankton were lost, in the case of Lake Mendota, because the fish that consume the things that eat the zooplankton were being eaten by the sports fish that the US Fish and Wildlife were stocking the lake with. 

They stopped putting in pike and European trout (don't ask me the species, I'm not a fish person), and allowed people to take any and all of those species when they caught them, but the native sunnies, and a different trout and something else had to be released.  The population of fish that eat the fish that eat the zooplankton rose back to pre-European levels, the zooplankton now started consuming mass quantities of algae, and there was no algal bloom on the lake again.

As a student, I remember being able to walk across the lake on the algal mat that bloomed every summer.  The smell mid-summer from the lake was awful when you sat at the beer garden at the Univ of Wisconsin, which is right on the lake.  And the mosquito problem was notable, even for a place like Wisconsin, where the state bird is the mosquito.................

I remember professors saying that algae PUT oxygen into the water, so how could the algal blooms be causing a problem?
Think it through..................

Think you have the answer?  then read on.......

Sunlight only penetrates one or two cells deep when a mat starts to develop. By the time a mat is thousands of cells thick, the cells on the bottom of the mat are no longer alive, and the bacteria grow so fast on all that dead sugar-containing algal material that the bottom side of the mat goes anaerobic by the time the mat is just maybe 10 to 100 cells thick. Expand that problem over the whole of one end of the lake, and you can imagine the smell, and the mosquitos happily eating all those bacteria and getting to adult size in no time flat.......

Steve got the USDW to change the fishing regs, and within one summer, the algal blooms practically disappeared, and the mosquitos are now just normal at the beer garden.......If an effort was made to add the necessary organisms to the lake, if the regs would prevent people from using chemical fertilizer to the lawns around the lakes and streams, even those few mosquitos would likely not exist either? 

What would birds eat? Worms. All those worms that would be back in the lawns, where they are supposed to exist........but can't because of the toxic level of chemicals poured on those lawns.  OK, we are all working on putting an end to that insane amount toxic material going on soil, right?