For years I was unhappy with the results of our tree fertility program using available fertilizers on the market. After attending a talk by Dr. Elaine Ingham many years ago on the soil food web, my partner and I decided to try compost teas. Once we experienced the power of compost tea on a lawn installation we decide to make compost tea the foundation for our tree fertility program.

9/16/05 New lawn install treated with AACT. This picture is taken after two 4” rain events, 4 days apart.

We use standard soil injection equipment to inoculate the root zone with highly fungal teas. By placing the soil biology in the rhizosphere of the tree roots we help colonize the root hairs with beneficial biology, which enables the plant to choose which soil microbes it will take advantage of by the exudates the plant roots excrete. This allows the plant to choose and direct its growth and who will be most beneficial at that specific point in the growing season. The rest of the microbes either go dormant or become food for other biota. This process mimics what nature does in a natural setting, allowing the plant to dictate what is best for itself at that point in time. One significant benefit is that the nutrients are kept in the root zone, being retained by the soil biology and eliminating nutrient loss. Once the plant decides what it needs, it will release exudates which will trigger biological activity in the root zone and nutrient uptake will resume.

As we have seen with compost tea applications to lawns reducing compaction, so too is this evident with relieving compaction in the root zone of trees. As the biology increases in the root zone and becomes active, this increased activity begins to open up pore spaces for water and air to move deeper into the soil profile. Roots can follow fungal hyphae deeper into the soil profile and organic matter can begin to increase as roots grow and die and soil organisms go through their life cycle adding to the organic matter in the soil. This process adds long term organic matter and makes a home for soil organisms, improving the environment for roots to grow.

Here is an example of the impact compost tea can have on a tree. In 2004 and 2005 we treated this dogwood for anthracnose (a leaf fungal disease) with foliar sprays. In the fall of ’05 I recommended removal because the tree had so much die back, virtually no foliage and was continuing to decline. It suffered from improper pruning, target canker, poor placement in the landscape and road salt impacts. The client wanted to try to save it, so I suggested trying to soil invigorate it with CT and corrective pruning. It was invigorated in the fall of 2005 and has not been done again since. All foliar sprays were stopped. This picture was taken on April 30^th this spring. Flower buds abound, the tree is beginning to bloom, the client is very happy. As you can see the wounds still exist but the tree is prospering.

Compost teas are a wonderful tool that can be used to promote the health of plants but like everything else is not the silver bullet to all plant health care problems. All other cultural practices must be adhered to in order for plants to flourish in the environment. We must also keep a vigilant eye on events in nature that can have a negative impact. We are all familiar with the negative impacts of pesticides and chemical fertilizers that can set back soil organisms, but nature itself can also be devastating with droughts, floods and torrential downpours. In a managed landscape it may become vital to introduce soil biology to facilitate quick recovery from these challenging events.

The key to making compost tea starts with acquiring the best quality compost. We only use compost that we can get a compost bio-assay on. We blend vermi-compost from a certified organic farm in Pennsylvania that has proven to be effective in field applications, along with local “compost tea” quality compost and our own ramial wood compost. We try to get the greatest diversity of biology into our teas. We have a small commercial brewer which has been tested and has proven to brew consistently, a quality aerated compost tea.

Small shed housing the Compost Tea brewer.

Harvesting the Compost Tea

Compost Tea in our spray tank ready for application.

Testing is continually done with the Soil Food web lab in New York along with our own “in house” microscope observations. Working closely with the lab, a formula was developed to insure that the most effective teas are applied based on the plant material we are treating. (A soil test is recommended to the client as an essential part of the treatment program. Unfortunately many decline spending the money.) Cleanliness of all equipment is paramount, so the equipment is cleaned daily after brewing or applications are made. The tea is kept aerated all day long to prevent anaerobic conditions from occurring. Amendments are added to the tea based on need, but care must be taken as large amounts can have a detrimental effect to the biology in the finished tea.

On a closing note, we have seen a significant decrease in insect damage on properties we have maintained over the years, therefore reducing the cost for plant health care treatments and allowing for a more sustainable landscape.

Last November/December my phone was abuzz with reports from many clients in Southeastern Massachusetts, letting me know of these little “whitish” moths flying around porch lights during the evening hours. I noticed on several properties, as we raked leaves, moths swirling about at waist height and quickly retuning to the ground. This is a sure sign of the presence of winter moth. It appears we will be having a heavy infestation of these non native caterpillars this spring.

The male moth is the one we see flying about in the evening hours. He is seeking a female to mate with. The female is virtually wingless, so she walks up the stems of trees depositing her eggs wherever she may in a hap hazard manner in cracks and crevices, under lichen and along branches. These tiny eggs will begin to hatch at around 50 growing degree days, usually in early April. It appears that hatching will occur as buds swell on the host plant. They then hang on a thin silk strand and get transported on a breeze upward into the canopy of the tree, where they wriggle their way into the leaf or flower buds and begin eating. To me the caterpillar at this point looks a lot like a green eye lash. The longer it takes for the bud to open the greater the damage they can do before a spray can be applied to stop their feeding. If the flowers are eaten then there will be no fruit. These non native caterpillars have no natural enemies so the damage they inflict can be tremendous. They feed on a variety of deciduous plants like blueberry, cherry, apple and crab-apple, maple, oak, etc.

To control these caterpillars can be very challenging prior to their entering the free feeding stage, which is when the leaves unfold and begin growing. Horticultural oils can be applied prior to bud break in an attempt to kill off the eggs by smothering them. This is a most environmentally sound treatment and we have had very good results on ornamental trees that were not flowering due to winter moth infestations in the past. The oil spray reduced the infestations and flowering occurred, much to the clients delight. It is much more difficult to have similar results on very large trees because it becomes harder to gain complete coverage.

Once the winter moth is free feeding Bacillus thuringiensis (kurstaki), B.t.k. can be used with great effectiveness and safety on the younger instars stages of growth. One must remember that the B.t. must be ingested to work and only the leaf material that was covered will have the B.t. on it, as the leaf continues to grow. Spinosad then becomes the next most effective and least toxic material for control of larger winter moth. Caution must be used around bees, as it is highly toxic to bees, till the material is dry. At full maturity the winter moth will be about 1 inch long.

If trees have been seriously defoliated, watering will become critical to the plants survival. Care should be taken to properly water weekly during the dry part of the season. I would recommend deep slow watering once per week. Do not use chemical based fertilizer as they are salts.