116 3rd St SE
Cedar Rapids, Iowa 52401
Curious Iowa: How is compost produced from yard waste?
Cedar Rapids/Linn County Solid Waste Agency turns yard debris into free compost for Linn County residents
Jun. 30, 2025 5:00 am
The Gazette offers audio versions of articles using Instaread. Some words may be mispronounced.
Kelvin Bronner of Cedar Rapids puts grass clippings, orange peels, tree branches and other organic material into his YARDY, the large green carts Cedar Rapids residents wheel to the curb on collection days.
“Then, occasionally I make a trip to Mount Trashmore to get a few buckets of this great potting soil for free,” Bronner said, noting that he’s surprised that the quality compost is free to Linn County residents.
Bronner wrote to Curious Iowa, a Gazette series that answers readers’ questions, asking for a description of how what he puts in his YARDY cart is turned into the finished compost he picks up at 2250 A St. SW in Cedar Rapids.
We spoke to Joe Horaney from the Cedar Rapids/Linn County Solid Waste Agency to pull back the curtain on the process.
How is compost made?
In fiscal year 2024, the agency took in 20,516 tons of yard waste, and 8,870 tons of screened compost were distributed. Horaney said that as fiscal year 2025 wraps up this week, he anticipates the totals will be similar to 2024.
He said the agency has returned to its pre-derecho numbers. After the 2020 derecho devastated Cedar Rapids’ tree canopy, the agency took in more than 40,000 tons of compost. About 28,000 tons of compost was distributed that year.
While some cities in Linn County, like Marion, have their own process for turning yard waste into compost, all Linn County residents can drop off yard waste at 2250 A St. SW. The City of Cedar Rapids is the agency’s biggest customer, Horaney said, and many private landscapers use the agency as well.
When yard waste arrives at the agency, city employees and agency staff remove large garbage items that may be contaminating the load.
The agency uses aerated windrow composting as its method for turning natural debris into “superfood for your lawns and gardens,” Horaney said.
After the load is moved through a grinder, the material is worked into long, narrow rows called windrows. Horaney said that depending on the time of year, the natural debris will sit in the windrows for about six to eight months where it “cooks.”
“The internal temperature, and again, (it) depends on the time of the year, will be anywhere from about 130 to 170 degrees,” Horaney said, “and that’s when, if there’s any weeds that were in there, those will all get killed off.”
While compost cooks faster in the summer heat, during the winter you can watch steam rise from the windrows.
He said that the agency has about 40 different windrows making up 8.5 acres.
Staff monitor the temperature of the windrows and water them during dry spells. Horaney said that water from a retention pond on site is recirculated into the windrows. During July, for example, they are watered about once every two weeks.
According to compost site supervisor Zac Hornung, about 5,000 gallons of water are used daily “to add moisture to our compost rows and for dust suppression.”
Agency staff aerate the piles using a Scarab compost windrow turner machine about once every two weeks when the temperature reaches around 170 degrees.
“A Scarab machine goes over the top of the rows, basically picks them up, then drops them back in place,” Horaney said, “and so that means oxygen is getting into the cooking process.”
After that, the material goes into a curing pile where the compost rests. Finally, the compost is run through a screening machine, removing large chunks that didn’t break down during the cooking process.
Horaney said that before the compost is made available to distribute, batches are tested at an independent lab.
“And then it’s certified by the U.S. Composting Council to say ‘Hey, it met these requirements,’” Horaney said, “and then we make those (results) available on our website too, so folks can actually see what is in the compost.
“That’s the biggest question you get is like, is this stuff safe? Am I going to get a bunch of weeds growing up in my lawn? If (folks) have any concerns about what’s inside, they can take a look at our results on the website.”
Agency staff will load pickups, trailers and larger vehicles with compost. Small amounts are self-loaded, so bring your own shovels and buckets. Compost is only available at the agency’s Cedar Rapids location.
Compost is free for Linn County residents but commercial businesses and out-of-county residents have to pay.
“We’re a government agency, but we do not receive taxpayer dollars, so all of our services, programs, operational costs, they’re actually all covered by our tipping fees,” Horaney said.
He said that the tipping fee at the compost location doesn’t completely cover all of the operational costs — like staff time and equipment used to produce the compost — so it is subsidized by the landfill tipping fee.
The tipping fee is increasing on July 1. The new cost to bring in yard waste will increase by $2 to $32 per ton. It also will be $32 per ton to purchase compost.
What is compost good for?
“It looks like dirt, but it’s not dirt,” Horaney said of compost. “It’s a nutrient rich soil amendment.”
He said that for existing lawn, compost can be used as a top dressing. Spread a quarter inch of compost across the lawn and then water it. The water is needed for the nutrients to make their way into the lawn.
“You don’t want to plant directly into compost because it is so nutrient rich — it’d be too much for (plants). It could fry it, basically,” Horaney said, “but if you add it to your soil and work it in, it’s just so good for it.”
“You always hear people talking about when they’re putting new homes in and there’s just clay and they’re putting turf right down on top of clay,” he said. “If you put a layer of compost in between there, it’s just going to make it so much stronger.”
Compost is available year-round when a supply is available. If there is leftover compost, they can retain it as the compost will hold its nutritional value, but in recent years, they’ve had more demand than supply.
“The demand for it is really — depending on the weather — April and then May … we do see a big drop off after Memorial Day week,” Horaney said.
“And there are commercial customers that, if we allow them to, they would come in with semi loads and take everything that we have … so we limit how much they can purchase because we always want to have a supply on hand, at least through summertime, for residents.”
What can go into YARDY carts?
YARDY carts can be filled with yard waste like leaves, sticks and twigs and grass clippings. Compostable items like fruit and vegetable peelings can be deposited as well. Some items that work in home compost piles are not accepted, like paper towels, napkins, paper plates and coffee cups, and animal bedding and cat litter. These materials can cause challenges at the composting facility.
Horaney said that the agency prefers not to receive dryer lint.
“So much of what’s in lint is synthetic fibers, which won’t break down in the composting process,” Horaney said, “or if it does, it takes a really long time.”
Compostables can be collected in a paper bag, which can also be deposited in the YARDY cart. The City of Cedar Rapids also suggests keeping a countertop compost bin in your kitchen to collect scraps.
Disposing of organic material in your YARDY cart may leave debris stuck to the side of the cart. Be sure to rinse your cart if you experience this.
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Comments: bailey.cichon@thegazette.com
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