Page 21 - ALG Issue 3 2024

DIVERSITY
enzymes, hormones, microbes, nutrients and plant growth compounds found in the original mature compost.
The compost can be left loose in the water but is usually contained and submerged in a mesh bag. If the compost is not bagged, the tea will need filtering before use.
If a bag is used, microbes, nematodes and nutrients will be filtered through the material to give a liquid feed that can be applied with a watering can or a sprayer. NCT may contain non-beneficial anaerobes if the air surface of the container cannot provide enough oxygen for aerobic respiration in the lower levels of the water. Regular stirring reduces the likelihood of anaerobic conditions occurring.
The finished tea is diluted with rainwater until it is the colour of weak tea, or 10:1 ratio of water to tea, It should be used immediately.
Actively Aerated Compost Tea (ACT or AACT)
Aerated Compost tea (ACT) offers advantages over that made without aeration in that it contains more micro-organisms, as the aeration and added nutrients provides favourable conditions for them to multiply during the 24-36-hour brew period.
When making Aerated Compost Tea, the mixture is brewed with an added microbial
food source, such as molasses, which is a simple sugar for bacteria and more complex sugars such as Fish hydrolysate for fungi, seaweed and kelp fertiliser or rock dust can also be added.
The use of worm castings or good mature aerobic compost produced by hot composting. is recommended.
A means of constant aeration during the brewing process is required to provide an aerobic environment of at least 6 ppm of dissolved oxygen.The pump should produce enough bubbles to agitate the liquid.
Once the tea has been decanted, the brewing equipment should be thoroughly cleaned and dried before reuse.
ACT can be applied both as a soil drench or as a foliar feed.
Bucket Aerated Tea
The simplest method of making aerated Compost Tea uses a 20-litre or 5-gallon bucket normally aerated by two or more aquarium aerator stones or bubblers. As a frequent compost tea maker I have purchased a larger circular aerator which fits the bottom of the bucket to provide better aeration.
The technique is similar to making NACT. Half fill a five gallon bucket with compost, having broken up any lumps, and fill to within 3 or 4 inches of the top with
non-chlorinated water. About an ounce
of black treacle (molasses) is stirred in.
The solution is aerated by the aquarium aerators/bubblers weighted so that they sink to the bottom of the bucket.The bubblers should provide sufficient aeration, but the solution is best stirred regularly throughout the 2-3 day brewing process.
At the end of this time, the aerator pump
is turned off, and the brew left to settle for about 30 minutes.The liquid can then be carefully poured into a clean bucket without disturbing the sludge which can be added to the compost bin.The liquid portion of the brew can be filtered through an old pillowcase, tea towel, or pair of tights.
An alternative is to purchase a small compost tea brewer. I use a Symbio 25 litre brewer to make ACT for our allotment.The compost is put in a 400-micron compost tea bag and suspended in rainwater. I
add black treacle and seaweed extract
as additional sources of nutrients and a 12-36-hour brewing time.
Aerated compost tea should be applied as soon as possible after the aeration ceases as the aeration and added nutrients will have resulted in a microbe level that cannot be sustained.
Rod Weston
Stokes Wood Allotments Leicester
Allotment and Leisure Gardener | Issue 3 2024 | 21