Compost study yields tree-mendous results

While muckraking is deeply rooted in journalism, it has branched out quite nicely into other fields as well.

Horticulture, for one.

That was the scoop shared last week by environmental engineer Tammy Thomas, who outlined findings from a local four-year compost field study during a briskly-paced 20-minute presentation before the La Conner Town Council, Mayor Ramon Hayes and other town officials.

Thomas termed the use of compost in tree-cropping as “very promising” based on extensive trials conducted in the La Conner area.

The La Conner Waste Water Treatment Plant has for years sold composted biosolids — rich organic material resulting from the treatment of sewage sludge — to various commercial ventures, primarily landscapers, and more recently to the Swinomish Tribal Community for application at nearby Similk Beach Golf Course.

“Every year we’re selling more and more,” said plant operator Kelly Wynn, among those on hand for Thomas’ report at last Tuesday’s council session.

Thomas said the effectiveness of compost in the planting and nurturing of trees is beset with many variables. Factors include location, soil and tree types, the amount of compost applied, and the degree of tilling undertaken, to name a few.

“A lot of the research that’s out there now,” she explained, “has to do with what’s happening in Florida, and that really doesn’t relate much to us here.”

But there is at least one general rule of thumb, according to Thomas.

“You never want to plant anything in 100 percent compost,” she cautioned. “There’s just too much organic matter, which can cause root rot.”

But double application of moderate depths of compost — between two and three inches each — when well tilled have produced positive results, especially among giant sequoias and various birch trees, she said.

Studies have also shown merit in what Thomas called “pushing the envelope.” By that, she meant initially applying and tilling up to six inches of compost, with a more modest application made on the second crop, followed by “going heavy” again on the third crop.

Thomas, who has worked with the town as a consultant, said commercial composting offers added benefits when one focuses on the big picture.

“Composting is an important step,” she stressed, “toward eliminating waste and reducing the carbon footprint.”

Residential composting has already built up a loyal fan base.

Voicing support Tuesday was Town Council member Bill Stokes, who said he top-dressed his tulips at home with four inches of compost and was more than pleased with the outcome.

“Those tulips,” he said, “are coming up crazy with no weeds.”