Compost Tea: What is it and can I use it?

The trend of using liquid extract from compost to fertilise your plants is becoming more widespread, but the so called ‘compost tea’ is not free from controversy. Here is a brief introduction to compost tea.

The ‘tea’ is not, in fact, a ‘tea’-

Well, obviously. But ‘tea’ implies certain qualities, namely that there is an infusion, or essence which is mixed or brewed into water. And while many qualities of the solid compost might filter into the tea, the valuable fertility-enhancing quality, or at least some of it, does not. This is because the microorganisms in compost tea that decay and enrich your garden are those who dwell in water, not on the solid matter which will remain. Unlike a tea which captures the ‘essence’ of the infused plants, compost tea contains only the nutrients & living organisms that can transfer to water.

2. Storage-

Compost tea does not store well. The breakdown of organic matter requires oxygen which, as we all know, is not abundant in water. Anaerobic decomposition (decomposition without oxygen) can produce a finished product rich great & valuable stuff like compost leachate, which has a variety of beneficial uses distinct from tea, but also risks harming plants if applied directly (see Bokashi Juice on this topic).

3. Use with care-

Compost tea is a versatile & quick way to give your plants an extra nutrient boost. However it is not its own substance- rather it’s a diluted blend of whatever was in the compost to begin with. This means that some non-plant composts can deliver unbalanced or unhealthy chemicals into the tea, without the added nutrition of solid compost. High nitrogen, manure-based compost will produce high nitrogen tea, and this could potentially burn plants if too much is used. Rather than some magic potion that will nurture your plants indefinitely, the tea will be a diluted blend of what’s already in the mix. The content of the tea will depend entirely on the composition of your compost- bear this in mind as you mix your tea. It is also work diluting tea for plants that are not in urgent need of extra nutritional help.

4.The benefits of compost tea-

Compost tea is versatile & useful for assisting weak plants. If used correctly it can help development quickly and without depleting your stocks of ready-to-use solid compost- most of us don’t have the space for extensive composting. If you do your research and take care not to overuse, you might find your plants come back stronger & healthier than in previous years.