Humates and biochars have been around for quite some time, but within the past five to 10 years, lawn care operators (LCOs) have begun to recognize the value they provide in improving soil health and feeding the plant.

“There’s a renewed interest because of the regulatory pressure that’s coming down in the industry,” says Jeremy Bigler, landscape channel manager for LebanonTurf. “People are looking for new ways to maintain performance that doesn’t involve traditional fertilizers. Across the board, there’s a trend to get more into natural-based products.”

To understand the full scope of benefits stemming from humate and biochar products, Landscape Management called on Bigler; Tony Goldsby, research agronomist at The Andersons Plant Nutrient Group; and Web Cowden, COO of Mirimichi Green.

Humate quick facts

Typically blended into other products (often at a rate of 1 to 5 percent), humates can improve the soil structure by helping with water retention, improving drainage, upping the efficiency of nutrients and humic substances and increasing aeration of the soil. They’re relatively safe products with no potential for turfgrass injury, Goldsby says.

Humates also increase a soil’s cation exchange capacity (CEC), which allows the plant’s root system to more easily take up nutrients, Cowden says.

“CEC is important because this function determines the level of exchangeable cations (or nutrients) a soil can hold,” Goldsby says. “As the CEC level increases, the ability to retain nutrients in the soil grows as well.”

The cost of using humate products is usually between $40 and $150 per acre, Goldsby says, but the price is typically offset by the increase in nutrient efficiency.

He recommends a spring and a fall application of a humate product at a rate of 40-120 pounds per acre. Application in conjunction with mechanical aeration will aid in getting the product into the soil profile, and using humates during overseeding or new turfgrass establishment can improve germination and subsequent root development, Goldsby adds.

Before using humates, it’s important for LCOs to reference the product label and understand how much humic material is in the product.

Biochar basics

Made from burnt biomass such as wood, switchgrass and coconut husks, biochar products are porous and typically resemble honeycomb, according to Cowden.

“No two biochars are the same,” Cowden says, adding that a good biochar typically features a high-carbon, low-ash content. If the ash content is too great, the pH level may be too high to serve as a good growing medium.

Biochar will pull water into its pore spaces and wait until the plant needs it. A permanent carbon structure (with a half-life of 200-400 years), biochar can hold air and nutrients until the plant requires them and hold contaminants. In sandy soil systems, using biochar can also help reduce nutrient leaching.

Cowden says it’s important to ensure the biochar is inoculated or precharged with nutrients or other materials before putting it in the soil. “If you put raw biochar in the soil, it’s going to start pulling nutrients away from the soil into its pore space. It becomes a taker before it becomes a giver,” he says.

As with humates, it’s important to read labels prior to application.