Aerated compost tea is becoming more and more mainstream, as people catch on to the immense benefits of using tea that is brewed properly. Today I want to summarize an interesting trial that was done recently, using compost tea, kelp, humic acids, mycorrhizal fungi, and organic fertilizers.

The main goals of the Harvard University project were to restore the soil health without chemical fertilizers and pesticides and determine the cost of implementing such a program campus-wide. There will also be many opportunities for education, research, and outreach.

This is a big deal! Harvard is actually thinking of going organic? Why would they want to do that? Perhaps there is some merit in this stuff.

They are doing many of the things that we teach at Gaia College and that I discuss on my website. It’s always nice to be able to show you that other people are using these products and practices, rather than you just taking my word for it.

I’ve outlined their schedule below. The test plot was 1 acre:

April 1

Sprayed 300 gallons of compost tea (I’m not sure if this was diluted in water or not. If undiluted, it seems like a lot, as the research shows typical usage of 5 gallons/acre, and occasionally up to 20 gallons for a soil drench, but you can’t overdo it, so it certainly doesn’t hurt).

The tea was mixed with 1 gallon of humic acid and 1 quart of kelp.

Applied 8lb/1000sqft of a granular humate (humic acid powder).

Applied 10lb/1000sqft of Turf Pro Granular, which seems to be some kind of humate/organic matter.

April 8

Aerated and overseeded.

April 15

Applied 1/2″-3/4″ compost and seeded bare spots.

May 2

Measured grass root depth at 6-8″ in test plot vs. 2-3″ in the control plot.

Injected compost tea, humic acid, kelp, and mycorrhizal fungi into the root zone around trees.

May 20

Applied a “half-dose” of North Country Organics 5-3-4, which contains Natural Sulfate of Potash, Phosphate Rock, Colloidal Phosphate, Oyster Meal, Kelpmeal, Greensand, Natural Sulfate of Potash/Magnesia, Vegetable Protein Meals, Animal Protein Meals, Natural Nitrate of Soda, Compost, and Dried Whey (some of these things are counterproductive, but I imagine the good will outweigh the bad).

June 11

Sprayed 300 gallons of compost tea, mixed with 1 gallon of humic acid and 1 quart of kelp.

June 25

Applied another “half-dose” of North Country Organics 5-3-4.


It was visually clear that the test plot was healthy and looked great compared to the control (I don’t know what they did to the control, but I infer that it was conventionally maintained). Root growth was 2 times that of the control. Nitrogen increased form 25-50lbs/acre to 100-150lbs/acre.

Irrigation was decreased by 30% and was expected to decrease by 50% in the long run, with the potential to save the school 2 million gallons of water a year. They were also able to mow half as much since they weren’t forcing top growth with chemical nitrogen.

As a result of this trial, all 16 acres at the Harvard Yard are now organic. They expect the maintenance costs to be the same as under the conventional program.

I have attached a short slide show that is really, incredibly well put together. There are some great photos in there, too.