How the Farnhams Turned a Bouncy House Blower into a Composting Hack

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Adam (left) and Tracy (right) farnham.

When Adam and Tracy Farnham first began improving their pastures, they hauled in loads of horse manure from local farms and quickly turned it into compost using a method called aerated composting.

“I built really long windrows of manure about 5 ½ feet high and about 150 feet long with an aeration pipe running underneath,” Adam explained. “Then I set up a bouncy house blower motor at the end on a timer and it ran around two minutes every hour until it was done composting, which took about six weeks.”

Unlike a traditional manure compost pile, aerated composting uses perforated pipes and a small blower to push air through the heap. The steady airflow speeds up decomposition, cuts odors, and generates enough heat to kill parasites, fly larvae, and weed seeds.

From Piles to Bins

The Farnhams’ two concrete manure bins and aeration system.

The Farnhams have since upgraded to two concrete manure bins with a roof and adapted the  aeration system to fit. Covering the manure—whether with a roof or tarp—is essential for both composting and water quality. If piles get saturated, they shift from fast, aerobic decomposition to slow, smelly anaerobic decay. Rain also leaches valuable nutrients, carrying them into and potentially polluting nearby waterways.

Their new setup uses a U-shaped configuration of perforated pipes with end caps and a blower attached to a solid discharge pipe.

“It’s not a fancy in-ground blowing system,” Tracy said. “It’s literally just pipes we set down, and then we fill the manure over them. It’s super simple.”

The results came quickly. 

“We had the thing packed full to overfilling and now it’s down to about half,” Adam said.

More Benefits of Composting

A small green fan is attached to a solid discharge pipe (not pictured here). This fan sits at the edge of the manure bins and pushes air through the piles. you can see the steam rising from the composting manure.

As manure decomposes, the pile typically shrinks by about 50 percent and converts nitrogen into a less soluble form, reducing the risk of nutrient runoff into waterways. Compost also benefits grass and other plants: rather than delivering a quick nitrogen surge, it releases nutrients gradually over time. 

Smart Spreading

Finished compost is a valuable soil amendment, but it’s best to test your soil first to know what nutrients you really need (learn more about soil testing here). Spread a thin layer—about ¼ to ½ inch—between late spring and early fall (April to September), when grass is actively growing and able to absorb nutrients. Give each layer of compost time to work its way into the soil and avoid spreading more than three or four inches in a growing season to prevent excess nutrients from polluting waterways.

By turning raw manure into nutrient-rich compost and applying it with care, the Farnhams are cultivating healthier pastures and helping keep water clean—a lasting benefit for their horses, their land, and the whole community.

Manure-spreading Guidelines

  • Only apply manure/compost to pastures during the growing season. Generally, grass grows from March - October. Manure should not be applied to pastures during the winter because grass is dormant and will not take up the nutrients. Excess nutrients on winter pastures can runoff and pollute waterways and groundwater. 

  • Test your soil’s fertility. A soil test will provide information on your pasture's current nutrient levels and how much fertilizer (nutrients) you need to apply for optimum grass growth. 

  • Check the weather forecast!  The risk of nutrient runoff from applied manure/compost is generally lower when there has been no significant rain prior to application to saturate soils, and limited (<0.20 inches) rain forecasted within three days after application.

  • Apply manure/compost at an agronomic rate. Spread it at a level that supplies the right amount of nutrients for crop needs without over-applying.

Want to know more? Reach out to meet our farm planners!


This project (WQC-2022-SnohCD-00101 Nutrient Runoff Reduction From Agricultural Lands in Snohomish County) was made possible with a Washington Department of Ecology Centennial Clean Water Fund grant.