Valley Bounty: Compost

Mike Mahar has been making compost since he was a kid. “I grew up around it,” he explained during a recent conversation.

Mahar was raised on a dairy farm down the street from Bear Path Farm in Whately. At the time, Bear Path was owned by Bill Obear, and Mahar and his brother would lend Obear a hand from time to time, helping him turn the windrows.

Years later, when Obear was ready to step away from the business, Mahar was the perfect fit to take over. He bought the business in 2016 and he’s been at the helm ever since.

Compost is a soil amendment that can be used to fertilize plants, build soil organic matter and soil structure, and enhance soil microbial activity. Compost is the result of breaking down organic waste materials and it’s useful for anyone growing plants, from home gardeners up to commercial farmers.

“To make compost, you need two-parts carbon to one-part nitrogen,” explained Mahar. “That’s what we call ‘the recipe’.”

The carbon in Bear Path’s compost comes from the Three County Fairgrounds.

“We take all of their bedding from the horse shows they have throughout the year,” Mahar said.

The primary source of nitrogen in his compost is cow manure, supplied by Bar-Way Farm in Deerfield.

To begin the process of breaking down his ingredients into compost, Mahar mixes the manure with the horse bedding. By mixing the materials together, it rapidly increases the rate of the natural decomposition process.

“The microorganisms that are breaking the materials down need oxygen to reproduce and breed,” Mahar said.

That’s why he uses a large front-end loader to lay the mixed material out into long rows, called windrows. The windrows ensure that there is good airflow reaching the piles, supplying the microorganisms with oxygen.

Once laid out into windrows, the mixture quickly begins to heat up.

“The microorganisms’ reproduction and their eating are what gives off heat, and the heat is what kills off weed seeds and pathogens in the compost. So that you have a nice weed-free product in the end,” Mahar said.

To ensure that all the weed seeds have been killed off by the time his compost is finished, Mahar closely monitors his windrows to make sure they reach at least 140 degrees for a period of two weeks.

As the microorganisms do their work, the pile settles. So Mahar uses the front-end loader to flip, or “turn,” the windrow over periodically.

“The turning adds air, which speeds up your process. Which is why we can get a finished compost in under a year’s time,” Mahar explained.

It typically takes around seven months for Mahar to finish off a batch of compost. By the time it’s finished, it barely resembles the ingredients that went into it. It has a different particle size, the moisture content is different, and it has lost its manure smell, “because compost is a very stable product versus cow manure, which is very acidic and full of nitrogen,” Mahar said.

Most of Mahar’s customers are homeowners and backyard gardeners. Some buy in Bear Path compost to incorporate into their soil as they till in the spring before planting vegetables. Once incorporated, “your nutrients are right in there in the soil for your plants to use,” Mahar explained.

Compost can also be a useful tool for patches of perennial plants. “By putting the compost on as a top dressing, the nutrients will still be available to the plant, and it will also act as somewhat of a weed suppressor,” said Mahar.

As we’re all adjusting to our new home-bound socially isolated lifestyles, it’s a great time to get out and spruce up the garden for spring. And fortunately for everyone involved, Mahar will deliver compost straight to your house.

“I’m just a single person doing the delivery, so it’s very easy to have minimal contact with the customers,” he said. Feel free to keep your distance. Just point and he’s happy to dump the compost and take off.

You can learn more about Mahar and Bear Path Compost at

While Mahar is fortunate to have a business model that is easily adjustable to the COVID-19 pandemic, many farmers do not. Visit for more information about how you can support local farmers during this challenging time.

Noah Baustin is the Communications Coordinator at CISA (Community Involved in Sustaining Agriculture)