Compost Tea & Extract

Reviewed 10th July 2021.
Making Aerated Compost Tea.
  • I make two 15 litre batches of aerated compost tea regularly and spray the brew on the foliage of my garden plants.  I do this to boost the community of beneficial microbes on the leaves which helps increase uptake of nitrogen from the atmosphere and provides a protective barrier against airborne plant pathogens.
  • The brewing process is about growing beneficial microbes extracted from a small quantity of freshly made compost and fed with small amounts of seaweed and fish extract.  These microbes grow rapidly during the 24 hour aeration process, and the tea is alive with them when its finished.
  • The finished brew is sprayed onto the garden without delay so the beneficial microbes don't run out of oxygen....More
Building a Compost Tea Brewer.
  • My brewer is made from easily obtained components usually available from your local hardware store or plumbing supplier.  The pump and the aquarium heater, however may only be available at specialist pet stores or from an on line supplier.
  • The bubbler is designed to be easily disassembled for cleaning and disinfecting between brews (without leaving anaerobic residues in place after reassembly).
  • This unit is very effective for brewing batches of 15 litres of compost tea.  The air pump generates plenty of turbulence in the water so beneficial microbes are extracted from the compost and kept supplied with oxygen during the brewing process....More

Compost Extract
  • I make compost extract and apply it by watering can directly to the soil in my Ecobeds, on the lawn and around the base of fruit trees.  I do this fairly regularly since the extract is simple to make and a very effective plant stimulant and pest controller.
  • It helps maintain diverse colonies of beneficial microbes in soil and is especially useful in an Ecobed's soil where isolation from other soil bodies makes microbe diversity a potential problem.
  • I use fresh compost which has been in contact with the ground for a few weeks, but has been covered to limit dehydration and stop leaching if it rains.  2 large handfuls of this compost are put in a paint straining bag, and the bag closed with string.  
  • A 20 litre food quality pail is filled with clean rainwater or filtered mains water, and the bag of compost immersed in the water.
  • The bag is massaged vigorously in the water for 60 seconds to extract the humic acid and microbes from the compost, or until the water turns dark brown.
  • The bag's remaining content is recycled through the composting process or simply added as mulch to the soil beneath trees and shrubs....More