How to make Compost Tea

using our 5gal tea kit

Download and Print the "Cheat Sheet" here:

How to make Compost Tea (to print).pdf

Download PDF • 218KB

Watch the video here:

https://www.youtube.com/watch?v=R4iBcaTuHTA

It all starts with a good compost - your source of microbes

• the best and safest types of compost to use in compost tea are: thermal aerobic compost, vermicompost, or aged Johnson-Su compost. Avoid uncomposted manure or compost made with only manure, as these composts may contain human pathogens and will only add bacteria to your soil.

• make sure your compost has been maintained at ~40% moisture, stored in a breathable container, aged less than 1.5yrs for peak activity.

• ideally, your compost should be checked under a microscope or the provider should be able to provide a report to show that the compost meets or exceeds biologically complete standards (Table 1).

• You may want to try to match the microbial successional stage of your compost (indicated by the F:B ratio, Table 2), with the successional stage of your plants.

Table 1. Minimum Requirements for Biologically Complete Compost (from Ingham 2005).

Microbe Group	Biomass	Quick Check (at 1:10 dilution)
Bacteria	>135 ug/g	More than 5 in one field of view at 400X
Fungi	>135 ug/g	More than 3 whole lengths across 25 FOVs at 400X
Protists (Amoebae+Flagellates)	>10,000 /g	2 in 25 FOVs at 400X
Nematodes ("good guys", no root-feeders)	>100 /g	1 nematode in 1 slide (scan at 10-40X)
Potential pests, pathogens, and anaerobic indicators	0 root-feeding nematodes, 0 spirilla, <5 ciliates/slide, more fungi than oomycetes (O:F<1)	Minimal to none (a few ciliates are OK).

Table 2. Choosing the right compost for your plants using the F:B ratio

	Early Succession	Mid-Succession	Late Succession
Plant Community	Grass, Brassicas	Vegetables, Crops	Vines, Shrubs, Trees
Microbial Stage	Mostly bacteria (F:B<.2)	Balanced (F:B ~1)	Mostly fungi (F:B>1)
Compost Type(s)	Aged manure, most commercial composts	Thermal compost, vermicompost	Johnson-Su compost, static pile composts

PLAN YOUR BREW ~1-2 days of intended application time, and use immediately when it comes off of air. Teas only last maximum 8 hours, and decrease in quality over time.

MICROBES LIKE IT WET - Spring and fall are the best times to apply tea or extract. Immediately before or after a rain works well too. If applying as a foliar, wait until rain has passed and leaves are dry.

READY TO BREW?

1. Fill 5-gallon bucket about 3/4 full with dechlorinated, ambient temperature water

   1. Use well water, rain water, or chlorinated water treated with a drop of humic acid (or a teaspoon of a good compost)

   2. Allow ~6hrs for cold water to come to ambient (outside) temperature

2. Insert the airlift manifold, elevate the air pump above the water line eg. on top of a chair

3. Add 2 cups of compost in to compost tea bag, close bag

4. Massage tea bag in water, breaking up clumps and circulating water through the compost for ~60 seconds.

5. Tie tea bag under the downspout of the airlift manifold

6. Plug in the brewer, ensure water is flowing through the downspout

7. Add pre-measured organic microbial foods to water (never exceed 200mL in a 5gal brew, and never more than 1tbsp molasses)

8. Brew for 12 - 48hrs depending on ambient temperature (Table 3)

9. Remove tea bag from bucket -- dump spent compost in to garden

10. Apply at a rate of 1L tea to 50 sq m (20gal/acre standard)

    1. For soil - mix ~1L compost tea in a wide-nozzle watering can and top up with water (up to 1:20 with water), apply evenly to soil surface in spring or fall, or before a rain. Repeat until all compost tea is used.

    2. For foliage - mix ~1L compost tea with 1 part water (1:1) and spray on buds/leaves/flowers/fruits using a backpack sprayer

    3. If using a sprayer with a pump, ensure pressure never exceeds 50psi.

11. Clean! Disassemble manifold and use a toothbrush to brush all crevices. Wipe inside of bucket with a washcloth, especially in the corners. Option to use a cleaner like hydrogen peroxide or vinegar to reach hard to clean areas. A dirty brewer can introduce potential pathogens to future brews.

12. Option to add additional amendments just before application (eg. mycorrhizal inoculant).

Table 3. Brewing times versus ambient air temperature

Ambient air temperature	Brew time
10 - 15 C	36 - 48 hrs, use more microbial foods
15 - 25 C	24 hrs
25 - 30 C	12 - 18hrs, use less microbial foods

Application Rate

1 yard of compost (~1000L) treats 528 acres!

At an application rate of ~2L of compost (in a compost tea) per acre, 0.5L of high-quality compost makes a 15L brew, which treats 1000sq m. See Table 4.

Table 4. Application Rates - Compost Tea

Compost Used	Concentrated Tea	Area Treated	Size Comparison
-	1L	~70 sq m (750 sq ft)	Half a tennis court
-	4L	~280 sq m (~3000 sq ft)	Small residential lot
500mL (2 cups)	15L (4gal)	~1000 sq m (~11500 sq ft)	Large residential lot
1.6L (~7 cups)	50L (13.2gal)	~3600 sq m (1 acre)	Market garden

Use as soon as possible. Microbial communities change by the minute and can degrade as soon as they come off of air.

For foliar treatments, dilute up to 5 parts water and spray using a low-pressure backpack sprayer or pump. Dilute with extra water (up to 20 parts) if using as a soil drench.

Use low pressure (<50psi) equipment to surface drench or foliar spray for all microbial products.

Last but not least

CLEAN YOUR EQUIPMENT by running fresh water through all tubes and pumps. Wipe or use a brush on surfaces and crevices. Option to flush brewer with a gentle cleaning solution.