Sugar: usually glucose because it is rapidly metabolized by virtually all microorganisms. In the real world, microorganisms normally live on sucrose (table sugar that contains one molecule of both glucose and fructose linked together by a chemical bond), and polysaccharides such as starch (many glucose molecules linked together into a large polymer for energy storage). In order for sucrose or starch to be metabolized by bacteria, the bacteria must make enzymes that break down sucrose into free glucose and fructose (sucrase) or the starch into individual glucose molecules (amylase). This takes time and energy and slows bacterial growth. Scientists hate slow bacterial growth, because it wastes their time.

Protein: usually soy or animal protein that has been pretreated with enzymes in order to cut the protein into small pieces. The enzymes are called proteases and the process is called proteolysis. This occurs naturally in the soil. Microorganisms cannot ingest large protein molecules. They have to bring them into their cells either as free amino acids or small peptides (small fragments of proteins). By electing to predigest the protein, the bacteria don’t have to secrete as many proteases into the culture broth to break down the proteins. Again, this speeds bacterial growth.

Vitamins: synthetic vitamins are sometimes added, but generally dried yeast is added as a food and vitamin source. Yeast contains the highest concentration of B vitamins of any known organism. Feeding yeast extract, as it is called, is a cheap way to provide the bacteria with pre-made vitamins. Bacteria can make most of their own vitamins, but this takes time and slows growth.

Minerals: salts such as sodium chloride, magnesium sulfate, etc. often are added to supplement the minerals already present in the protein powders. These minerals are soluble in water unlike many minerals that are found in the soil.

As a scientist and organic gardener, I understand how both bacteria and plants grow in their natural environments. Plants are passive organisms, and require substantial help in order to grow in the soil. This help is provided by soil microorganisms. Plants can make all their own proteins, sugars, and vitamins, but they cannot do so without help from their friends in the soil (see the essay on the nitrogen cycle). There is one exception to this rule. If the plants are provided with all the necessary soluble minerals, they can grow in the absence of microorganisms, e.g. hydroponically. However, unless a mineral can dissolve in water, it cannot enter the roots of a plant. It is a simple concept, but one that is easy to forget. In the lab, plants and microorganisms can grow nicely in water that has been spiked with soluble minerals. The microorganisms won’t grow as fast (because they have to make all their proteins and vitamins from inorganic building blocks), but they will grow as long as they are provided with a source of sugar. Plants make their own sugar from CO2 in the air. In the soil, minerals exist in forms that are not appreciably soluble in water. As a consequence, minerals can sustain plant life, but their presence is not sufficient to insure rapid and sustained plant growth. In the soil, this is the role of microorganisms and one of the reasons composted organic matter is such a powerful fertilizer.

From the perspective of an organic gardener, it would be wonderful if every square millimeter of soil contained all the right microorganisms for maximally breaking down organic matter. It doesn’t. Did you ever notice a new lawn that grew unevenly? The lawn appears to have major and minor gaps where the grass seed didn’t seem to take. This happens so often that many homeowners won’t take the risk and “order in” grass turf from a commercial supplier. One of the reasons for the “gap effect” is the lack of a proper mix of microorganisms necessary to provide nutrients to the seed and eventually the grass plants. The microorganisms are sporadically present because many homeowners use inexpensive “potting soils” rather than topsoil as a nutrient foundation for their lawns. As discussed in another essay, most potting soils have no nutrient value for plants. Bugs cannot thrive in them because they consist primarily of shredded bark. No bugs-no plants, unless you want to feed your lawn inorganic fertilizers from now until eternity.

I have been mixing Bug Juice for years. It is simply a variation of what I do in the laboratory—growing large amounts of bacteria for a particular experiment. However, in the case of Bug Juice, I am growing bacteria from compost piles so they can be strategically distributed around the garden. In the process, I found that plants loved the growth media I developed, whether it included bacteria or not. This media is made from common household items and is described below.

Bug Juice™ is designed to stimulate the growth of many different types of bacteria and fungi. In a compost pile, we need bacteria that can degrade cellulose, pectin, protein and starch. Compost piles are optimal growing areas for bacteria because they are moist, warm, and aerated. Hopefully, they do not contain a lot of junk, such as sawdust (from woods that contain turpentine) and citrus—both of which can inhibit the growth of microorganisms.

Compost piles in the garden should be designed to “turn over” waste organic matter as rapidly as possible so the compost can be used elsewhere in the garden. When the compost is added to the garden soil, the microorganisms responsible for degrading the compost are also transferred. This is common sense, but it is easy to overlook the value of these microorganisms in the soil ecosystem. No patch of soil is equal to another. They are all different, and they reflect their differences in the manner to which they can support plant growth. If a patch of soil is devoid of digestible organic matter, the bacteria present in the soil will not be able to degrade leaves, grass clippings or pasteurized cow manure, for that matter, if they are roto-tilled into the soil. Eventually these bugs will make an appearance, but the process of becoming established in the soil is slow. Did you ever hear someone tell you that it took three or more years of mulching to get the soil to a point where it produced great tomatoes? This is the reason we developed Bug Juice™ as a cheap innoculent for compost piles and depleted soils.

Most people have under performing compost piles, if they have them at all. So, if you want to go into the home bug growing business, all you need is some really good fresh compost, and a five gallon bucket of Bug Juice. Throw the compost, a handful, into the bucket, stir it a few times a day for aeration, and leave it in the sun. Cover the top with some cheesecloth if you have it. This keeps the flies out of the Juice. The bugs will begin to grow in the juice. After one week, you should have some potent home grown liquid fertilizer.

This is what you need in order to make Bug Juice™.

One 5 gallon bucket.
Corn starch
Bread yeast
MaxGro™ our fishmeal product, or another source of protein. Blood meal will work.
Ripe fruit, such as plums, apples, apricots, peaches, watermelons, peeled bananas or whatever. No citrus.

The Bug Juice™ Formula

Fruit: The fruits mentioned above contain sucrose, proteins, various vitamins and other nutrients, easily digestible cellulose and pectin. They are the perfect food for soil microorganisms. Pit the fruit, and smash it so it can be more rapidly digested by microorganisms. It should be mush. Add 1 pound or so to the bucket. Decaying fruit that has fallen off a tree is the best. Just save it for making Bug Juice™.

Cornstarch: Starch is present in all organic matter as a form of storage energy. Bugs need to degrade it in the soil in order to obtain a carbon source for their metabolism. Add 5 tablespoons to the bucket.

MaxGro™ or blood meal: MaxGro™ is a heat sterilized fishmeal that has a high nutrient and growth promoting value for plants and microorganisms. It is the protein source for the bugs and the source of biochemical building blocks for the auxin and cytokinin plant growth hormones. Blood meal is a poor substitute, but it is more readily available. Add 5 tablespoons to the bucket.

Yeast: Yeast is a cheap source of B vitamins. It is also a source of cytokinins and protein. Mix two teaspoons of yeast, two teaspoons of sugar and one teaspoon of bread flour to 2 cups of warm water. When the yeast stops foaming, it has consumed most of the sugar. Add 2 tablespoons of corn starch, 1 tablespoon of bread flour and allow the mixture to sit for 2 hours. You are adapting the yeast to the starch. This is important. In order to break down starch, the yeast must be induced to secrete the enzyme alpha amylase. You want to promote this reaction. Most sugars in the soil are in the form of starch—not sucrose.

You have now mixed the ingredients, a handful of good compost and added water. Mix periodically to aerate the mix and leave the bucket in the sun. After one week, start applying the Bug Juice™ to the compost or table scraps you have collected, or directly to poor soil. Bug Juice™ can be directly applied to plants, trees, grass, whatever. It is disgusting to look at, but it is a powerful organic “nutrient soup” for the soil. And you made it. You are now officially a backyard scientist.

Bon Appetite.

Copyright 2001© Stephen Martin, Ph.D
Chief Scientist, Grouppe Kurosawa
All Rights Reserved