How to Make Actively Aerated Compost Tea

How to properly make ACT or aerated compost tea

Difficulty: Moderate

Instructions

Things You'll Need:

• Bucket/Container
• Air Pump
• Diffuser or Glass Bonded Air Stones
• Worm Castings or Compost
• Food source (unsulfured molasses, fish hydrolysate, alfalfa meal, etc)
• Sprayer without a 90 degree nozzle tip for foliar applications

1. 
   Motor for 5 gal. brewing system

   Make sure your air pump has a minimum of .08 cfm/gal of water. In our 5 gal system, the pump we use is rated at 51 liters/min. This is CRITICAL to make sure you're maintaining good dissolved oxygen levels.

2. Fill your bucket with water (approx. 4.5 gallons). If your water contains chlorine, you will need to remove it by aerating the water for 30 minutes or letting it sit out for 24 hours. Any water used to mix with the tea upon application will need to be treated as well. If you water contains chloramines, you will need to add ascorbic acid (a 500 mg. tablet of Vitamin C will do the trick). You can also use humic acids (put in enough to turn the water a dark brown color)

3. 
   example of a coil system, but you may use airstones or diffuser as well.

   Attach the diffuser or airstones to the end of the tubing. The diffuser needs to stay on the bottom of the bucket. I use a coil system in order to make sure there are no "dead zones" in the bucket.

4. 
   Mesh bag for compost

   Once the water is bubbling, add the compost, inside of a 400 micron mesh bag. You may substitute a paint strainer. Do not use cheesecloth or nylons.

5. 
   Adding the compost and foods

   Place the compost into the bucket and add any foods (see recipe in the tips section)

6. 

   Allow the tea to brew for 24-36 hours. After which, it may be placed into a watering can or sprayer to be applied to your plants (both foliar and soil drench). Make sure your sprayer does not have a 90 degree nozzle tip.

Tips & Warnings

• 5 gal brewer Recipe 1 heaping cup of compost ½ cup of humic acid 1 to 3 T. of kelp 1 tsp. of non-sulfured, blackstrap molasses
• The tea should have no smell or nice earthy smell. If it stinks, that means it went anearobic and don't use it!
• Airstones will need to be cleaned THOROUGHLY or discarded after a few brews.
• Be sure to clean your brew immediately after using it.
• The tea needs to be applied within 4 hours after shutting off the motor. Do not attempt to refrigerate or store the tea.
• If the mesh bag with the compost is just sitting on the bottom of the bucket, you will need to suspend the bag off the side of the bucket and run another airstone or diffuser directly into the mesh bag.

Resources

• Lab Tested Compost Tea Brewing Systems
• Scientific info. from Dr. Elaine Ingham
• Teaming with Microbes by Jeff Lowenfels

[tadhussey]

on 7/29/2009 dtwelloh,

You're correct that there are much cheaper ways of making compost tea. However, most of those methods have not been tested using lab or microscope work, and many fail to actually brew up any biology in their tea. Getting a good pump and distributing the air properly is essential. I've looked at tea made from basic aquarium pumps and usually what I see is just a bit of bacteria swimming around, rather than the full complement of bacteria, archea, fungi, and protozoa.

[dtwelloh]

on 7/29/2009 Seems like a very expesive way to make something so simple as compost tea.