Brewing Aerated Compost Tea


The Rose Society of Tucson

At a recent meeting of The Rose Society of Tucson, a fascinating presentation took place on the subject of organic fertilization by Tom Pew and Troy Hollar of Merlin Organics which is based in Tucson.

Their system is being utilized to fertilize all the turf and trees at the University of Arizona except athletic fields.

While they explained the benefits of their system and the bare bones outline of what they do, Tom and Troy didn’t have time to delve into the details of their organic process.

So here is the rest of the story.

In short, their system replaces conventional synthetic fertilizers as millions of beneficial microbes are brewed in a special tea and then applied to the soil. Once these microbes work their magic in the soil, nutrients are available in the soil to plants.

At the core of this system is Aerated Compost Tea (ACT).

This is not manure tea where you simply put steer manure in a burlap bag which is lowered into a 25-gallon container filled with water and let it steep for several days similar to a tea bag in water. That is a completely different process.

ACT involves the use of air being pumped into water similar to a fish tank. The holding container must be absolutely clean along with the tubes that emit bubbles before the tea can be made. In addition, no trace of chlorine can be in the water which is easily achieved. The air that is being pumped into the water only needs to be on for 5-10 minutes to flush chlorine out, according to Pew.

Once this water is de-chlorinated, that is the time a mesh bag filled with high quality compost is lowered in the liquid. Pew’s compost of choice at this time is Tank’s Green Stuff 100% Organic Compost which is teeming with microbes in itself after being infused with Bactifeed, a product used in Tucson’s parks to permeate beneficial microbes into the soil.

In addition, other products are put in Pew’s brew, including liquid fish hydrolysate, algamin (cold pressed kelp), Turf & Garden Pro (has 8 percent fulvic acid, 3.6% humic matter, 6.5% humid acid), humus and worm castings.

He also has experimented with alfalfa in his brew with great results.

When you add up the cost of purchasing these items along with a 25-gallon container and air pump, it is expensive.

Different ACT brewing kits are available on the internet from 5-gallon on up but at a steep price.

Lauren Kettenbach, our esteemed Vice President, came across plans from Oregon State University to build a homemade brewing kit complete with octagonal frame made of PVC pipe that is inserted into a 25-gallon container (see diagram).

It is a fraction of the cost from a commercial brewing kit. The most expensive part was the air pump which ran around $50 and is hooked up via tubing to the PVC pipe which has small holes drilled in certain locations.

After the ingredients are introduced to the water, the air pump is turned on as the bubbles are pushed out of the PVC holes and rise to the surface. It is kept on typically for 14 hours and then immediately sprayed on the soil of plants.

Incredible Challenge

After fine tuning his ACT for years, Pew formed Merlin Organics with Hollar. They were both convinced that their organic fertilizing system could change the landscape of fertilization.

The first big client they approached was the grounds maintenance department at the University of Arizona as they asked the powers to be if they could show them how efficient and powerful their system was.

 They were given the difficult task of converting an area in front of old Bear Down Gym that wouldn’t grow any grass into an oasis of green.

Despite being told that the soil in the area was backfill from construction projects and was heavily compacted, Pew and Hollar accepted the challenge.

According to Hollar, they first used a machine to take soil plugs out of this area to aerate the soil. Then they spread Tank’s Green Stuff 100% Organic Compost generously over the area and also feather meal and Leonardite which added carbon into the soil.

The final touch was a spray of Pew’s Aerated Compost Tea which infused millions of beneficial microbes into the soil and compost.

After six weeks, the area had turf growing extremely well to the surprise of Arizona turf experts. Merlin Organics then was allowed to use their system on all of the turf in the mall area of the University of Arizona. Then it ultimately expanded to all other areas at the University, except athletic fields, as the system replaced conventional synthetic fertilizers.

To maintain the beneficial microbe population, ACT has been applied monthly most of the year. In certain areas of the mall covered with grass, they are turned into glorified parking lots during football and basketball games which compacts the soil. Those locations are aerated as explained before with plugs being taken out and compost being added with the other products mentioned at certain times.

Pew and Hollar explained that once you go to ACT and this organic approach, you should not add inorganic fertilizer to the soil because these products will kill the beneficial microbe population and upset this powerful organic fertilization factory in the soil which also enhances worm activity as they thrive in the soil over time.

Pew had his ACT tested by Martha Hawes in the School of Plant Sciences at the University of Arizona.

A deadly pathogen for legumes named Nectria haematococca has been a serious problem in the industry for decades.

Initial testing by Hawes found that legume plants grown in water which had this pathogen died quickly. But with plants grown in the ACT made by Pew, they lived. If this holds up in future extensive testing, it will be a breakthrough.

Is ACT Ultimate Answer?

Different organic gardeners have claimed that ACT kills grubs in the soil and prevents mildew from forming on leaves and can even stop mildew from spreading on foliage.

If this is true, it would be a huge breakthrough for rose growers.

According to Pew, it is still too early to give a glowing endorsement of ACT in these areas until additional research is done which proves these claims. Early studies, however, are encouraging.

According to the book Teaming With Microbes written by Jeff Lowenfels and Wayne Lewis, predator nematodes feed on protozoa, algae and other small members of the soil food web, including grubs, weevils, wasps and even small invertebrates such as slugs after ACT is applied to the soil.

The ideal brewing temperatures are from 50-80 degrees with ACT. Pew said that the biggest problem he has encountered with brewing compost tea is high temperatures because the compost tea won’t hold dissolved oxygen properly. This also is a problem at higher altitudes.

“The whole point of pumping in all the air is for the solution to stay aerobic,” said Pew.

“The last thing you want is for the solution to be anaerobic because there was not enough dissolved oxygen.”

Proven Methods For Rose Growing

When temperatures are comfortably cool in January-March in Tucson, your plants will not have as much active growth by utilizing a strict organic fertilizing system.

This is the prime growing season for roses in Tucson for the spring and is the reason synthetic fertilizers such as Magnum Rose Food are utilized. It is imperative to get the roses growing after they are pruned in late January so they bloom in mid-April.

If you don’t utilize chemical fertilizers and the bloom cycle is pushed back to late April or even May because of only utilizing organic fertilizers, it is a major mistake because hot weather will in all likelihood arrive by that time. The quality of blooms will be a huge disappointment.

Magnum Rose Food has the perfect mix of macro and micronutrients available to roses for ideal growth with big blooms. The formulation for this fabulous fertilizer was designed by Dr. Tommy Cairns of Studio City, Calif. who grows over 1,000 roses and is one of the elite rose exhibitors in the world.

Cairns also is one of the top chemists in the world. He has dissected soil conditions and everything involved in the rose growing process unlike anyone in the history of this hobby. He is not sold on the benefits of ACT for growing great roses

My wife Diane and I have utilized this fertilizer for a number of years in rose growing with fabulous results. In fact, I was on the American Rose Society Product Evaluation Committee when Dr. Cairns had initially introduced this fertilizer decades ago.

Everyone on the committee loved this product. Thousands of rose growers across the nation feel this is the best rose fertilizer on the market for this hobby.

Every week from September-mid-November and February-April, we have utilized a simple fertilizer program which has produced dynamic results as the solution is put on the soil of plants:

Week 1: Magnum Rose Food (1 TBSP to 1 gallon of water).

Week 2: Fish Emulsion (1 TBSP to 1 gallon of water).

Then you simply repeat.

I am not aware of any rose grower in the state of Arizona who utilizes ACT as the sole source of fertilizer for his plants.

Possibly someone in the Rose Society of Tucson will experiment with ACT in the future to find out how roses will perform.

Organic lobbyists typically sound an alarm that the use of chemical fertilizers sets off a vicious cycle. The more synthetic fertilizer you use, the more the soil food web is destroyed and the more fertilizer you will need to fill the nutrient void you have creased.

This is absolute hogwash and unproven. This has never, ever happened in my rose garden.

They also tell you that when chemical fertilizers are used, earthworms die. That is another bunch of malarkey. The soil of our roses have hundreds of earthworms which haven’t been impacted by Magnum Rose Food or other chemical fertilizers we have utilized over the years.

Value Of Using Organic, Chemical Fertilizers

Cairns, considered one of the top rose exhibitors in the world, said that roses are heavy feeders and require consistent levels of fertilizer with the different macro and micronutrients they utilize for superior growth.

” Every year, I always lay down a thick bed of mulch over the soil of my roses,” said Cairns.

“When it decomposes, it makes humus, and humus is fertile soil. Realizing roses are heavy feeders, you must give them an ample supply of nitrogen through the year at proper dosages and every other nutrient a rose requires for maximum production.

“Magnum Rose Food has it all, including three types of nitrogen for quick, medium and long acting feeding plus every other nutrient a rose requires, including phosphate, potash, magnesium, sulfur, chelated copper, chelated iron, chelated manganese, molybdenum and chelated zinc. Plus it has a soil penetrant.”

He added that utilizing alfalfa pellets or meal are highly recommended as well.

“My other product from the Grow More Company is called Jumpstart, and is a compost tea utilizing alfalfa meal and other products. Alfalfa is one of the few organics that yields a reasonable amount of nitrogen when it decomposes. Many other organics steal nitrogen from the soil.

“In the commercial rose fields in Wasco, Calif., roses are harvested and those fields have alfalfa being grown the following year. They always bounce back with terrific roses following the year with alfalfa in the soil.

“The bottom line is that organic fertilizer has been around since farming was invented because there wasn’t anything else. People have used fish heads to feed their plants, Peruvian bat guano and many other manures.

“I don’t have anything against organic gardeners. It is a natural way to feet plants. If this wasn’t so, grass and trees wouldn’t grow and survive areas without people fertilizing them.

“For many home rose growers, you can utilize organic and chemical fertilizers in different ways for superior plant performance.”

Tom Pew’s Garden

I had the pleasure of visiting Pew’s home garden six years ago with Lauren Kettenbach. He explained his whole process of Aerated Compost Tea at the time.

He had several raised beds which had the richest, darkest soil I have ever seen. Over 40 years ago, he built the raised beds and had soil trucked in from Triple A Fertilizer which was the owner’s special potting soil mix.

Then over the next 40 years, Pew added a considerable amount of compost and other organic goodies such as used Starbucks’ coffee grounds which he got for free. Over the past nine years, he has utilized a sprinkler can to add fresh ACT to the top of the soil on a monthly basis.

For years Pew has looked at samples of his aerated compost tea under a microscope to see if microbes were growing at the rate he wanted.

His soil has such a massive amount of beneficial microbes now that he doesn’t find it necessary to add more aerated compost tea at this time.

At the time I saw his garden, tomatoes were 10 feet tall, and every single plant grew like gangbusters.

One interesting additive he gives his compost prior to adding it to his rich soil in his raised garden is baby oat meal which he sprinkles on top. He feels it helps with adding beneficial microbes, and other books back up his claim.

Special Book Available

If you are interested in learning more about the entire process of utilizing ACT for the organic growth of plants, Pew and Hollar highly recommend purchasing the book Teaming With Microbes written by Jeff Lowenfels and Wayne Lewis.

I purchased it in 2010, and it gives you a tremendous amount of solid information on achieving great soil which ultimately produces superior plants.

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