Eco Sustainable Village

PART-3

Making the compost

To make good compost tea, you need actively managed, mature compost; that is, compost that has been turned a few times and allowed to heat adequately so weed seeds and pathogens have been killed. Worm compost also makes excellent tea, without the hassle of turning or checking the temperature. Tea brewed from vermi-compost that has been made from a fair amount of paper and woody materials is also high in humic acid, an organic substance that is especially good for potted citrus or other trees and shrubs, or perennial plants.

Start with the right kind of compost
You can manipulate compost so it's dominated either by bacteria or by fungi. Which one you want depends on what you're growing and what kind of soil you have. You always want a bacteria-dominated compost tea for use as a foliar spray, whatever the plant. Bacteria-dominated compost is also best for applying to the soil before growing vegetables and herbs. Fungi-dominated compost is good for mulching around berries and fruit trees. But research has shown that a foliar spray of bacteria-dominated compost tea is extremely useful to prevent the foliar diseases that plague most gardens. Thus, most of us need only be concerned with making a bacteria-dominated compost tea.

For bacteria to dominate, compost should be made from a preponderance of green materials. You need a mix of 25 percent high-nitrogen ingredients, 45 percent green ingredients, and 30 percent woody material. High-nitrogen materials include manure and legumes, such as alfalfa, pea, clover, or bean plant residues. Grass clippings from the first two or three cuttings in spring, when the blades are lush and tender, qualify as high-nitrogen; the rest of the season, they're simply green material. Green material includes any green plant debris, kitchen scraps, and coffee grounds, which, although brown in color, contain sugars and proteins that bacteria love. Woody material includes wood chips, sawdust, paper plates and towels, and shredded newspaper.

When making compost, measure your ingredients by volume. Try to mix a whole pile at a time. To get it up to temperature and keep it there, you need a mass that measures at least one cubic yard. Moisten the pile as you make it so that it is damp but not wet. An easy way to tell is to pick up a handful of the material and squeeze it as hard as you can; only one or two drops should be squeezed out. Less than that, add water; more than that, let it dry out.

Once the pile is made, you can add kitchen scraps as they accumulate. Bury them in the center in different places to help maintain heat in the pile. Small additions don't upset the ratio. If needed, you can balance the green additions with shredded newspaper or wood shavings.

A good compost
The pile will heat up right away, as microorganisms start breaking down the material. The pile must stay between 135°F and 160°F for three days. At 135°F, weed seeds, human pathogens, most plant pathogens, and most root-feeding nematodes are killed. The pile shouldn't go above 160°F because at that temperature large numbers of the beneficial organisms begin to be killed.

Within a day or two, the center should reach 135°F. Measure the temperature with a long-stemmed thermometer. A 20-inch compost thermometer is nice but not necessary; I use my turkey thermometer. Just be sure to stick the probe deep into the center of the pile. Take two or three readings from several areas of the pile each day for the first week when you first start making compost, so you get a feeling for what is normal. If you make the same mix again and again, after several batches you won't have to monitor quite so closely.

When the temperature gets to about 155°F, turn the pile with a pitchfork or a shovel. This mixes the cooler materials on the outside to the center and brings air into the pile, preventing anaerobic conditions. Within a day or so, the pile will be back up to 155°F, and you'll need to turn it again. Expect to turn the pile every day or two for about the first week to get it and keep it in the 135° to 155°F range. After that, you can let it alone, maybe turning it once or twice more during the next few weeks. The more you turn the pile, the more the compost tends to become bacterial. That's because any kind of disturbance destroys fungi by breaking up their mycelia and helps the bacteria beat the fungi by bringing the foods bacteria need into range for the tiny individual bacteria.

As the compost matures, the temperature will drop gradually until, after six to eight weeks, the center of the pile is cool or barely warm to the touch. The compost is now ready.

 Brewing and using the tea

Once you have fully mature, nice-smelling compost, it's time to brew tea. You will need a 5-gallon plastic bucket and a few aquarium supplies: a pump large enough to run three bubblers (also called air stones), several feet of air tubing, a gang valve (which distributes the air coming from the pump to the tubes going to the bubblers), and three bubblers. You'll also need a stick for stirring the mixture, some unsulfured molasses (preferably organic), and an old pillowcase, tea towel, or nylon stocking for straining the tea. An extra bucket comes in handy for decanting the tea. Don't try to make compost tea without the aeration equipment. If the tea is not aerated constantly, the organisms in it will quickly use up the oxygen, and the tea will start to stink and become anaerobic. An anaerobic tea can harm your plants.

Also, keep in mind that tea made using this bucket method needs to brew for two or three days and then be used immediately. If you work Monday through Friday, start the tea on Wednesday or Thursday, so it will be ready in time to apply it on the weekend.

If you're on a well, you can use water straight from the spigot. But if you're using city water, run the bubblers in it for about an hour first, to blow off any chlorine. Otherwise, the chlorine will kill all those beneficial organisms you've gone to the trouble of raising.

Tea time
Once you have safe water, fill the empty bucket half full of compost. Don't pack it in; the bubblers need loose compost to aerate properly. Cut a length of tubing and attach one end to the pump and the other to the gang valve. Cut three more lengths of tubing long enough to reach comfortably from the rim to the bottom of the bucket. Connect each one to a port on the gang valve and push a bubbler into the other end.

Hang the gang valve on the lip of the bucket and bury the bubblers at the bottom, under the compost. Fill the bucket to within 3 inches of the rim with water, and start the pump.

When it's going, add 1 oz. of molasses, then stir vigorously with the stick. The molasses feeds the bacteria and gets the beneficial species growing really well. After stirring, you'll need to rearrange the bubblers so they're on the bottom and well spaced. Try to stir the tea at least a few times a day. A vigorous mixing with the stick shakes more organisms loose and into the tea. Every time you stir, be sure to reposition the bubblers.

After three days, turn off the pump and remove the equipment. If you leave the tea aerating longer than three days, you must add more molasses or the good organisms will start going to sleep because they don't have enough food to stay active. Let the brew sit until the compost is pretty much settled out, 10 to 20 minutes, then strain it into the other bucket or directly into your sprayer. You'll have about 2 1/2 gallons of tea. If you want, this is the time to add foliar micronutrients, like kelp or rock dust. Use the tea right away, within the hour if possible.

You can put the solids back on the compost pile or add them to the soil. There are plenty of good bacterial and fungal foods left in them.

Follow your nose
With any form of compost, solid or tea, bad smells mean bad business. Healthy, adequately oxygenated compost and compost tea should smell sweet and earthy. Never use a smelly compost tea on your plants. The true bugaboo is alcohol, a product of anaerobic decomposition that destroys cell walls. Roots tolerate only 1 part per million alcohol. That's a very small amount, and human noses aren't good at detecting it. Instead, we can detect all the other smelly compounds that go with anaerobic production of alcohol.

If your compost tea smells bad, add a second pump with more bubblers, and stir it more often. Aerate it until the smell goes away. Likewise, if your compost pile smells bad, turn it more frequently.
 

Using the tea
How often to spray your plants with tea depends on how healthy your garden is. In my garden, which has had no pesticide use since 1986, I spray my plants one time in spring, then let the beneficial insects spread the compost tea organisms around the plants in my garden, preventing any pest problems for the rest of the season.

Beneficial insect presence is a good indicator of your garden's health. If you don't have good levels of beneficial insects in your garden, then spray at least once a month, or as often as once every two weeks. Start when plants have developed their first set of true leaves.

To control damping-off, spray the soil with full-strength tea as soon as you plant. On trees and shrubs, spray two weeks before bud break, then every 10 to 14 days. You'll have to spray every 10 days if you have a neighbor who sprays pesticides, because pesticides kill the beneficial organisms as well as some of the pests.

Tea - Compost - Products results
Resources

The following are products that help resuscitate different organisms in the food web. The two main categories are:

	food resources for organisms to grow on,
	products that contain organisms.

Often inorganic minerals additions should be considered as well, such as Ca, Zn, Bo, Fe. Quite often, when life in the soil has been lost, so has the ability to hold micronutrients beyond the minimal level that the sand, silt and clay fractions of the soil can hold. Sandy or silt soils cannot hold many nutrients. Soils that are irrigated, or where significant rain or snow fall occur during some part of the year, mineral micronutrients will be leached and long-gone as soil organic matter was lost.

Bacterial Food Resources

Commercial products. Working with product companies, the following products have been shown to result in significant increases in bacterial biomass in the following conditions:

	Estecol and Hydra Hume Plus (Helena Chemical Company). Shown to increase bacteria in clay, silt and sand soils, in both lab greenhouse tests and fields trials in California. When bacterial biomass are below 5 µg per gram dry soil, apply 1 gallon per acre. If bacteria are greater than 5 µg but less than 100 µg per gram, apply 1 quart per acre. Repeat applications if bacterial biomass does not increase to desired level. It may be beneficial to apply a soil conditioner such as Ece-X to drive salt out of the soil, and add calcium products or rock dust or Eco-Min to replace lost or leached micronutrients.
	Blend (Advanced Agri-Tech, Pasco, WA). Testing has been done on particular soils in Washington and Idaho and shown to improve both bacteria and fungi.
	Simple sugars such as table sugar, syrups or molasses. The question always becomes how much sugar in what volume of liquid over what amount of land area. Dosages need to be worked out, but generally, try an increasing gradient of concentration. Start with 1 gram of sugar in 100 ml (1% sugar) and apply to a 1 meter square area. Apply a solution of 10 grams in 100 ml (10%) to another area, and a solution of 20 g in 100 ml (20%) to another area. Wait a week, perhaps two, and test to see if this was effective in increasing bacterial biomass. Be aware that too high a concentration of sugar will cause a bacterial bloom, and will cause symptoms of N-deficiency in the plants. Avoid concentrations that result in plant yellowing.
	Molasses - There are a few humic materials in molasses, giving molasses the dark color. Blackstrap molasses contains more of these humic materials than less thick and dark molasses suspensions. Test as above for rate.
	Plant extracts usually contain the sap of the plant material, which are combinations of simple sugars, protein, carbohydrates.
	Yucca extract is a product that appears to enhance "stickiness," selecting for bacteria that produce extracellular slime. About 1 pint per acre.
	Nettle extract contains an unknown compound with antibiotic-like qualities. Typically made in the same fashion as a compost tea, but using mown nettles instead of compost. Highly variable potency. Testing from batch to batch is required.
	Fulvic acids appear to be food resources for bacteria. Apply at about 1 quart per acre. The molecular weight of these "humics" is less than that of humic acid, and at least in some cases, supply food for bacteria more than fungi. More work is needed to understand the difference in microbial communities selected by fulvic versus humic acids.
	Yeast provides vitamins for bacterial growth. The kind of yeast is important, as Baker's yeast provides quite different sets of vitamins than Brewer's yeast, or champagne yeast, as examples. This material has not been well-tested for it's dose-response, so testing on your own land will be required.

Protozoa Food Resources

Protozoa eat bacteria. Therefore, anything that grows more bacteria will result in more protozoa eventually. The lag between more bacteria growing and the protozoa "noticing" this increase in food resource is about 2 weeks in the spring, about 4 weeks in the winter (not-frozen soil), and about a week in a warm, moist soil in the early summer. When soil moisture is below wilting point, the protozoa may never notice until soil moisture increases.

	Hay infusions are good sources of protozoa. Stick clean hay (no pesticides!) in clean water, keep warm, well-aerated and by day four, protozoa will be high in number. Bacteria grow on the sugars extracted from the hay. The protozoa that were dormant on the hay eat the bacteria. Algae will grow too, if in sunlight, but it's not a problem. The protozoa eat them too.
	Composts and compost tea. If compost is made correctly (see compost page), then both these material will contain tens of thousands, if not hundreds of thousands of protozoa.

Nematode Food Resources

Nematodes come as four types: bacterial-feeders, fungal-feeders, root-feeders and predatory nematodes. Predatory nematodes eat other nematodes, while the name of the other groups indicate what organisms they eat. Like protozoa, when the organisms that nematodes eat increase, then an increase in nematodes occurs, about 2 to 6 weeks later with many of these groups. The lag between more food and more nematodes is greater than for protozoa.

The only two good sources of material containing a wide diversity of beneficial nematodes are good compost and healthy forest 'O' horizons. BUT BOTH MUST BE CHECKED to make sure it does not contain root-feeding nematodes, or lacking beneficials. There's quite a bit of material labeled as compost that should only be sold as organic matter, and maybe not even that. Be careful - old growth forests that have been disturbed can have very sick soil. It can take ten years for the trees to start showing the effects of a compacted soil, or fertilizer impacts, or atmospheric pollution. Test the soil first to make certain it's ok.

Inocula of Bacteria and Fungi

	Commercial Inocula. Mostly just bacterial species are available commercially. Decisions on which set of bacterial species to buy depends on a whole list of things, and it is easier for you to e-mail the reasons you need an inoculum to SFI than for me to go on for another 400 pages to explain the things to think about. Don't ask us to make these decisions on the phone. Time to consider is required.
	There are two fungal inocula available on the market - Trichoderma and Gliocladium. These are two fungi that parasitize other fungi, and are quite effective at what they do. BUT, they stay alive only as long as they have other fungi to parasitize. One of the things agricultural and turf management has done is to destroy the fungal biomass in the soil. So, these fungi do a good job on the pathogenic fungi that are present when you inoculate them, but then they run out of food, and go to sleep. No more control. It's not the fungus' fault you didn't feed it.
	Compost is a great source of both the organisms and the food they need to do their jobs. A great diversity of bacteria, fungi, protozoa and beneficial nematodes occur in good compost. But beware! There is quite a bit of organic matter sold under the name of compost, and it's not worth the money spent on it. Improperly composted material can kill plants (phytotoxicity), and can add all kinds of nasty organisms, from fungal pathogens to root-feeding nematodes. Test the compost first, and know the conditions of composting before you buy the material. A good compost can grow grass directly seeded into 100% compost, and you will never see grass grow more beautifully. But so much of what is sold has serious salt, heavy metal and toxic anaerobic problems that care must be taken. See the Bio-cycle column papers that appear in the ARTICLES section of the website.
	Compost tea - a liquid extract of compost. One of the problems with compost is that it costs a lot of money to spread. Compost tea solves this problem because it can be applied through the irrigation system. Tea made from a GOOD compost - emphasize good - can significantly reduce foliar pathogens because it provides the organism and the food needed to make a good bio-film. We've pretty well documented Goal 1 for compost tea, but are working on Goal 2. How can we improve the tea making process so the most beneficial bacteria are present in the tea? Working with golf course folk, we should be able to tie this down fairly quickly.

Clearly, there is a great deal of work to be done to optimize application of Food web Technology. But the work that needs to be done is straightforward. Does this or that work better or worse in this condition? We need to get out there and see.

 For more details .............contact us

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Last modified: 04/08/06