While Cornellians are out enjoying Slope Day today, they may notice a strange green film spread across parts of Libe Slope. This strange substance, called hydro mulch, is used to help maintain Cornell’s substantial volume of lawns.
Hydro mulch is a bright green liquid mixture of water, grass seed, wood mulch and fertilizer sprayed from the back of a tank truck.
Its distinctive color is artificial, given from a dye added to make the substance blend in with existing grass.
“[Hydro mulch] is a quick way of seeding [our lawns],” said Pete Salino, landscape manager for the University Grounds Department. “We’ve been using it about five or six years, but it’s been around a hell of a lot longer than that.”
Hydro mulching is a type of a technique called hydro seeding, which was invented in 1953, according to Sekerez Landscape Services, a company which provides hydro mulching services.
Hydro seeding differs from hydro mulching only in that it does not contain wood mulch. That mulch component helps bond the grass seed to the soil.
“[Hydro mulching] is very convenient, especially on a [dry day],” Salino said. The mulch can retain water for longer durations and protect the grass seeds from Ithaca’s strong summer sun, he explained.
Hydro mulching is also one of the more cost-effective and efficient solutions to growing grass, Salino said.
Manually laying seed can take excessive amounts of time, especially on Cornell’s large campus like Cornell’s, while pre-grown sod can be very expensive.
The University uses big red tank trucks to distribute the hydro mulch.
The “Spray Baby,” invented by landscaper Richard Carlyon in the 1970s, was one of the earliest hydro seeders. It was a bulky, half-ton attachment carried around by a pickup truck.
In addition to trucks and hoses, hydro mulch can be delivered to larger areas via agricultural aircraft.
Outside of Ithaca, hydro mulching is used frequently in the construction of highways. The substance is sprayed out on the edges of the road to help combat erosion. Hydro mulching is effective at this because of its relatively quick germination rate of about four to six weeks.