Inoculant for Compost Tea
Worm castings and aerobic compost are the best inoculant choices. Worm castings are a great inoculant because worms use bacteria instead of digestive acids in their stomachs to break down food. The castings are rich in beneficial microorganisms, some of which have been found to be effective in breaking down certain contaminants. Worm castings are also a source of humic acid, which is a good food source for your tea. Similarly, good aerobic compost (especially thermophilic compost) is a great inoculant; if made properly, it should be full of beneficial microorganisms.
The quality of the compost used to make compost tea is really critical. The tea can only amplify the biology already present in the compost. So you want an incredibly biologically active compost, ideally one that has at least both bacteria and fungi, to serve as your inoculant. Compost piles that have been curing for three to six months are more likely to be fungal-dominated, while piles that have been curing for one to three months, tend to be more bacteria-dominated. I’ve heard several compost tea experts say that it can be difficult to get a good amount of fungi. If you can use a more fungal-dominated compost pile as an inoculant, that could give you a bit of an advantage. If you also happen to be cultivating mushrooms, you could try adding spent spawn to your compost to increase its fungal load.
Bacteria are very easy to grow in your tea — they are easy to extract and they like growing in the water. If you test your tea and find it to be fungi deficient but strong in bacteria, it is still good for inoculating your site with beneficial bacteria. You will just have to find another way to get replenish the fungi in your soil food web.
Food Sources for Your Compost Tea
The food sources you add to your compost tea will determine the composition of microorganisms that grow in it, as bacteria and fungi favor different food sources. Different recipes I found called for different ingredients, and these different ingredients allow you to select for a more bacterial or fungal tea. A mixture of these foods will create a tea with both bacteria and fungi, which is ideal for the remediation of contaminants.
Food sources for bacteria include simple sugars, simple proteins and simple carbohydrates. The most commonly used food source in compost tea recipes seems to be unsulphured molasses. Some other bacteria food sources include fruit juice, cane syrup and fish emulsion. Food for fungi include complex sugars, amino sugars and complex proteins. The most commonly used compost tea food sources for fungi are fish hydrolysate, kelp/seaweed and humic acid. Some additional food sources include fulvic acids, soybean meal, oat bran, oatmeal, fish oils, cellulose, lignin, cutins, rock phosphate dust, fruit pulp (oranges, apples and blueberries) and aloe vera extract (without preservatives). The more types of food added, the greater the diversity of species of microorganisms likely to be present.
