Page 20 - ALG Issue 3 2024

COMPOST
TEAS
In the past, liquid fertiliser was often made by soaking manure in a bucket of water. However, with increased knowledge of bacterial pathogens and
the increase in health and safety awareness, the idea of spraying liquid manure over the food we are growing to eat has fallen out of fashion.
Why risk Salmonella infection when it is easy to make compost and plant-based liquid feed to boost growth and increase biodiversity in the soil? In this article we will look at methods of using manure-free compost from the allotment to make compost teas and extracts. Plant-based teas will be considered in the future.
There are now a considerable number
of peer reviewed papers reporting that compost tea can improve plant nutrition and growth while helping to control pathogens.Therefore, it can be used with confidence, although, of course, the exact mix of microbes and nutrients will vary with every batch made.
Choice of Compost
The best home compost for making liquid feed is from a hot composting system
as this will tend to have a better supply
of beneficial microbes and higher fungal counts than from cold compost heaps. Hot composting also kills potential pathogens. Where the fungal count might be low, Fish hydrolysate or a handful of course oatmeal can be added to the compost a couple of weeks before brewing.
The compost should be added to unchlorinated water, preferably rain water, or if this is not available, a container may be
filled with chlorinated water and allowed to stand for 24 hours.
The water temperature should be such that the microbes grow and multiply with an ambient temperature of 180 C to 230 C recommended.
Before looking at teas which are brewed, it is worth considering two compost-based solutions that do not involve brewing.
Compost Leachate
Leachate is liquid run-off from the compost bin that has percolated through the composting material. It will contain dissolved or suspended materials and will include organisms from a mix of immature and mature compost collected as the water passes through the heap. It should not be used if it has an unpleasant smell. Leachate can be applied to the soil, round the plants or returned to the compost bin as an activator.
Compost Extract
Simple compost extracts can be made in minutes and applied immediately, making them very convenient if there is not enough time to brew aerated tea. Compost extracts require a larger volume of compost than
is used for brewed teas. Compost extract is made by agitating compost in a bucket of water, or by running water at pressure through compost. I put the compost in
a mesh bag in a large plastic container allowing room to stir the water.The bag enables the microbes to pass into the water while avoiding the need to filter the solution.
Non-Aerated Compost Tea (NCT)
NCT is made by brewing mature sweet-smelling aerobic compost in rainwater. The compost should be completely submerged in a barrel or bucket of water and regularly stirred for one to four days. The longer the soaking period the more organisms are extracted from the compost.
Soaking and regular stirring washes off microbes as well as removing soluble nutrients from the compost so that the finished liquid will contain the range of
20 | Issue 3 2024 | Allotment and Leisure Gardener
“The best home compost for making liquid feed is from a hot composting system”