Jun 1

PERMACULTURE: Compost Tea

By Mary ‘Klibs’ Dralle, for Let’s Talk Plants! June 2024.

Compost Tea

In Permaculture, we use three natural components to keep the soil healthy and alive: Compost, Mulch, and Compost Tea.

Compost is a result of a controlled aerobic (oxygen-required) process that converts organic materials into a nutrient-rich, biologically stable soil amendment through natural decomposition, as defined by the EPA. Microorganisms feed on the materials added to the compost pile during the process provided there is a good amount of water, heat and oxygen.

Mulch, however, is a layer of organic plant material applied to the surface of soil at a depth of 4-6 inches. In most cases, it is ground trees. This material has not been processed by soil microorganism mentioned above. We say, yet, because over time, it will become in place compost as it succumbs to breakdown with the right amount of water, heat and oxygen. As that happens, it will be necessary to add additional mulch on top to keep the soil covered and insulated at a temperature between 60º to 85º F to support optimal growing microbe conditions.

Compost Tea - What is the most efficient way to increase soil microorganisms and keep them well fed? Brew up a batch of compost tea. Once your garden has been established and it is utilizing the life in the soil, it is necessary to add more biologics and nutrients every six to eight weeks. While fertilizers add nutrients, compost tea adds more that will continue to support the soil.

The Benefits of Using Compost Tea as listed on The Old Farmer's Almanac website:

· Good tea improves soil health. A healthy soil is less likely to leach nutrients beyond plant root zones. If soil is nutrient-rich, the need for fertilizer is minimized.

· Compost tea improves the water retention capacity of soil, which reduces the need for frequent watering.

· Soil structure is improved with regular applications of compost tea. (Good soil structure is important for nutrient and water retention and accessibility.) The biological components in the soil create its structure. For good structure, all organism groups in the food web—bacteria, fungi, protozoa, nematodes, and micro arthropods—need to be present. When you add tea, you add these microbes.

· Compost tea helps loosen clay soils for air and water to move and helps sandy soils retain water and nutrients.

· Compost tea applications stimulate plant root growth. Deeper roots retain moisture better and help to reduce runoff.

· When sprayed onto plant foliage, compost tea adds beneficial microbes. By occupying leaf surfaces, these organisms prevent potential disease organisms from gaining a foothold.

· Compost tea combats the negative impact chemical-based pesticides, herbicides, and fertilizers have on beneficial microorganisms.

Unlike store-bought fertilizers, tea recipes can be developed and fine-tuned to target specific conditions and plant needs.

What is it exactly?

A liquid produced by extracting beneficial microorganisms from existing compost using a brewing process. While brewers can be purchased, making one is fairly simple and requires minimal skills of drilling, cutting pipe and assembly. It can be done on a small scale, in a 5-gallon bucket, or larger scale, using a 32 gallon 'trash' container. Please note: the 'trash' container should be either brand new or thoroughly cleaned, to remove any unwanted microorganism, before using it to brew tea. Once it has been used for tea, it becomes a dedicated vessel and should not be reverted back to former use.

How much tea to brew will depend on the size of your garden. For small scale home gardens, a 5-gallon system would be sufficient to maintain the space with regular tea every 6-8 weeks. In some cases, with high plant density, it may be necessary to brew a bit more often and rotate the areas where it is applied. Otherwise, larger capacity brewing equipment could be used.

Let's take a look at the components for a five-gallon system:

Description	UOM	Qty req'd	Vendor
One clean 5-gallon plastic bucket	ea.	1	Repurposed from a local bakery or deli
Eight feet of 3/8” clear plastic tubing, cut in half (may need to cut in half if there are two ports for air stones)	pkg	1	Pet Store
Aquarium Air Pump (be mindful of the ports and cut the clear tubing for the situation)	ea.	1	Pet Store
Air Stones (usually sold as a pkg of 2)	pkg	1	Pet Store
6.2 in. x 9.5 in. Disposable Paint Strainer Bags (2 -Pack)	ea.	1	Big Box Home Improvement Store
Two Thick rubber band, (One to close the compost bagOne to attach air stones to a rock or other heavy object)	ea.	0	Re-use any thick produce rubber bands such as the ones from store bought broccoli
Rock, fist size and a bit heavy	ea.	0	Any good sized rock from the yard will do

For large scale, the 25 (or 32) - Gallon Compost Tea Brewer from Oregon State University Extension Services had been the set of plans used to build a brewer for clients in the past and can be found from Dr. R.C. Anderson, Ph.D., with this link, https://www.wh6fqe.com/single-post/2019/08/01/131-diy-25-gallon-compost-tea-brewer.

This design is a good one.

However, the group at Harvard has created a simpler design that will be made for a new client next month. The full set of instructions can be found using this link, https://www.energyandfacilities.harvard.edu/sites/energyandfacilities.harvard.edu/files/documents/How%20to%20Build%20an%20Organic%20Tea%20Brewer.pdf

It is components are as followed:

Description	UOM	Qty Req'd	Vendor
½” PVC elbows	ea.	6	Big Box Home Improvement Store
½” PVC Tee	ea.	1	Big Box Home Improvement Store
½” PVC Adapter SxMPT	ea.	1	Big Box Home Improvement Store
10' 1/2" PVC pipe cut as follows:2 – ½” x 11 ¾” PVC pipe1 – ½” x 10 ¾” PVC pipe2 – ½” x 4 7/8” PVC pipe1 – ½” x 2” PVC pipe1 – ½” x 32” PVC pipe1 – ½” x 4” PVC pipe 1 - ½” X 36“ PVC pipe (to lay across the top of the barrel)	10 ft-length	1	Big Box Home Improvement Store
7/8 in. Wall-Mounted White Steel Spring Grip Clip Storage Hooks (2-Pack) 5 lbs.	pk	1	Big Box Home Improvement Store
400 micron mesh bag with drawstring (6.2 in. x 9.5 in. Disposable Strainer)	ea.	1	Big Box Home Improvement Store
6’ x ¾” rubber tubing	10 ft-lg	1	Big Box Home Improvement Store
¾” stainless steel screw clamp	ea.	1	Big Box Home Improvement Store
AquaMiracle Aquarium Air Pump Commercial Air Pump 600/1000/1200/1750GPH, 18W/35W/58W/120W Air Pump for Fish Tank, Hydroponic Air Pump, Fish Tank Air Pump Bubbler Pond Aerator	ea.	1	Amazon
Trash barrel	ea.	1	Big Box Home Improvement Store
Large watering can (Optional)	ea.	1	Big Box Home Improvement Store
Larger pump style sprayer (Optional)	ea.	1	Big Box Home Improvement Store
Required Tools: PVC cement PVC primer Drill with a 1/8” and ¼” drill bits Small hand saw or PVC Pipe Cutters

Once assembled, brewer would look like this -

Picture courtesy of instructions in link mentioned above.

Suggested Brew Vessel: Brute 32 Gal. Grey Round Vented Wheeled 'Trash' Can -

Picture courtesy of Home Depot Product Shot - this makes the best brewer as it has wheels and can move all over the garden.

Now that the brewer is assembled and ready for use, here are typical formulations used as suggested by Dr. Elaine Ingham in her book, Compost Tea Brewing Manual (5th edition):

Water - preferably well or rainwater. If using city tap water, allow to off gas overnight to remove the disinfectant monochloramine.	per 5 Gal	per 30 Gal
Recipe 1
Viable Compost (lbs.)	1.5	9
Soluble Cold-Water Kelp (lbs.)	0.05	0.3
Plant Extract Material (Yucca, Comfrey, Stinging Nettle, etc. - oz.)	0.35	2.1

Recipe 2
Bacterial tea for grasses - add components below to Recipe 1
Black Strap Molasses (oz)	1.6	9.6
Plant Extract Material (Yucca, Comfrey, Stinging Nettle, etc. - oz.)	0.6	3.6

Recipe 3
Fungal tea for trees - add components below to Recipe 1
Humic Acids (oz.)	2	12
Fish Hydrolysate (not emulsion in lbs.)	0.05	0.3
Add Mycorrhizal Inoculum at the time of spraying	~1 tsp per plant at the base	~1 tsp per plant at the base

Brewing Steps:

1. Fill up the brewing vessel with the applicable amount of water needed for the job.

2. As stated above, if using city tap water, allow water to off gas over night to remove monochloramine. Not doing this step will result in colored water with very few microorganisms.

3. Add the components needed for the plant(s) being fed.

4. Add aerator and brew for 24-40 hours

5. Once brewed, use a watering can or sprayer to apply compost tea to the whole plant. Start at the top and move to the soil.

6. Repeat every six to eight weeks to ensure plants have nutrients to sustain themselves.

Example of 5 Gallon Process from Start to Finish

Layout of parts:
	Put the bag into the water and drop in the rock with attached air hose. Plug in the air pump and watch it bubble. Cover with lid and brew.