Compost Tea

compostteaThe idea behind compost tea is fairly simple: soak organic compost in water (much like you would a tea bag in a cup) to obtain the soluble nutrients that are readily available for plant absorption. In most cases, a straining bag or filter is used to hold the organic material which makes for quick removal of the unwanted matter after the tea is done. The most popular “compost” products to brew tea from are worm castings, various manures, including bat guano, and vegetable compost.

The organic matter used will determine the nutrient makeup of the finished tea. For example, a tea brewed from fishmeal would be rich in nitrogen (and smell like death), while a tea brewed from high-phosphorus bat guano would be rich in phosphorus. This basic method of soaking organic matter in water to create liquid fertilizers has been around for many years. More recently however, with the addition of oxygen (usually achieved by using a cheap aquarium pump), growers have taken compost teas to a whole new level.

Oxygenation of Compost Tea

By adding small air bubbles to a classic compost tea, a grower can not only acquire the water-soluble nutrients from the organic matter, but also breed a much larger population of beneficial microorganisms. Many of the beneficial microorganisms found in soil are aerobic creatures.

This means they do well in oxygen-rich environments. The better oxygenated the environment, the faster these little creatures can reproduce (assuming there is an adequate food source). Growers using oxygenated teas will always produce larger populations of beneficial microorganisms than growers using non-oxygenated compost teas.

The idea behind compost tea is fairly simple: soak organic compost in water to obtain the soluble nutrients that are readily available for plant absorption

Carbohydrates to Supercharge

In addition to supplying oxygen directly to the brewing compost, growers looking for the largest possible populations of beneficial microorganisms should supplement a carbohydrate formula as well. Many of the microorganisms found around a plant’s roots have a symbiotic relationship with the plant itself.

The beneficial microorganisms will actually feed off carbohydrates secreted by the plant’s roots and, in turn, create enzymes that aid in the break down and absorption of nutrients. The beneficial microbes will also use the carbohydrates secreted by the plant’s roots as food in order to grow and reproduce.

By supplementing a carbohydrate formula into the tea, growers of high-value plants can facilitate the natural processes that happen in and around a plant’s root zone. This includes the growth and reproduction of many beneficial microorganisms. Compost teas supplemented with carbohydrates create even larger populations of beneficial microorganisms than compost teas that use oxygenation alone.

Additional Beneficials

For growers who cannot accept anything but the largest populations of beneficial microorganisms from their compost teas, there is the addition of beneficial microorganisms. That’s right, one way to ensure that you brew the most beneficials possible is to add a bunch of beneficials to your brewer.

If growers want the highest level of beneficials that are specifically designed for high-value plants, they should consider Tarantula and Piranha by Advanced Nutrients. These products work great in oxygenated compost tea brewers and are compatible with any organic substance. I have used Piranha and Tarantula, along with Bud Candy, while brewing worm casting and bat guano teas. The teas I created with these products were rich in nutrients and packed full of beneficial microorganisms.

Additional Filters for Hydroponics

Unfortunately, rich compost teas may be a nuisance for the hydroponic grower because emitters and pumps can easily be clogged and, frankly, make a mess out of everything. Hydroponic growers looking to gain the benefits of compost teas — without the hassle— should implement a triple filtration process.

Filter 1 (Initial Brewing Filter)

First, filter the organic material in the brewer. As previously mentioned, most gardeners use a screen bag or some other filtration to remove the bulk of the organic material from the tea upon completion. All gardeners should use this filter whether they grow in hydroponic systems or soil. After the initial filtering, soil growers can go ahead and apply the tea.

Filter 2 (Secondary Brewing Filter)

A smaller screened filter should be used for the secondary brewing filter. Some of the extraction bags sold at hydroponic retailers can actually be used as a secondary compost filter bag. You will be surprised to see how much additional sediment is collected on the second filtration. Organic purists can also implement a natural filter for the secondary filter.

I have seen some impressive natural filters built from five-gallon buckets and gravel. The idea is similar to a slow sand filtration process, except that all the microbes and soluble nutrients should not be removed. If used regularly, a natural filter will eventually create its own micro-ecosystem complete with its own beneficial microorganisms.

Filter 3 (Equipment Filters)

Last, but not least, organic hydroponic growers using compost teas should use filters on all pumps being used in the hydroponic system. Most submersible pumps come equipped with their own filter. In addition to that filter, a pump filter bag can be used to make certain that any remaining sediment in the compost tea remains in the reservoir and does not affect sprayers, emitters, or the plant’s roots.

By oxygenating the compost teas and supplementing them with carbohydrates and beneficial microorganisms, growers of high-value plants can produce the most microbial- rich teas possible. With the proper filtration, organic hydroponic growers can enjoy the speed and convenience of hydroponics while maintaining the quality and flavors of organics.