Any first-year agronomy student who’s been awake for even part of a semester can tell you that soil is at the root – pun intended – of plant health. But after centuries, probably even millennia, where improving plant growth meant focusing on adjusting the soils below, increasing numbers of agriculturalists and horticulturists of all persuasions (including golf course superintendents) are turning to a more direct method to supplement this tried-and-true approach. Foliar feeding sends nutrients into the plant through the leaf, bypassing any imbalances or inadequacies in the soil that might impede root uptake and allowing greater control over what the plant is receiving and when. We asked three superintendents to describe their foliar feeding programs.

Superintendent Ben Kelnhofer is entering his fourth season with a foliar feeding program at Mistwood Golf Club. In the past the course had used a variety of different foliar products, but when Kelnhofer started at Mistwood one of his goals was to take a more consistent approach.

He relies on a high-load foliar nutrition program that provides more essential plant nutrients at lower use rates. The program features a built-in adjuvant package that improves nutrient uptake, according to the manufacturer.

“There’s a surfactant in it, and I seem to get a really good, quick response with a nice, slow feed associated with it,” Kelnhofer explains.

He applies the foliar products only on his putting surfaces, and says that Mistwood’s Penn A4 greens are a big reason why he selected these particular products.

“I’m not a big fan of urea with A-4 greens; they tend to react a little better to the nitrate form of nitrogen,” he says. He has found that the products in his foliar program are well-balanced in the percentages of different nitrogen forms: About 8.5 percent nitrate, 1.3 percent urea and just a little ammoniacal.

“The products are very versatile, and that’s why I’ve gone with them,” he states. “I’ll use a 10-0-0 calcium product because I know on a year-to-year basis I’m going to need the calcium. I’ll use an amino package. I use these same products. … I stay on that program every two weeks – it’s between 1/10 and 2/10 of a pound [nitrogen].”

Kelnhofer follows that foliar program throughout the season. The foliar program supplements biannual granular applications on the greens.

“We use the foliar during the 90 days of summer, which I consider to be June, July and August,” he explains. “Our first granular app goes down in May, and we track that for about four to six weeks. Once that starts to slow down, we start with the foliar program.”

Typically, weather has little impact on the foliar applications, Kelnhofer says.

“You can spray it in the heat, it doesn’t really matter,” he explains. “If it’s too wet and we don’t want the weight of the sprayer on the greens, we’ll hold off a day, but that’s about it.”

Dairy Creek Golf Course | San Luis Obispo, Calif.

As director of golf operations for San Luis Obispo County, Josh Heptig oversees the maintenance of three courses and one zero-waste park, which he helped create to promote recycling and other sustainability initiatives throughout the entire operation of Dairy Creek Golf Course. He says foliars were used prior to his arrival in 2008, but one big change since then was the introduction of a compost tea foliar program in 2011. The concept actually helped to drive the course-wide effort toward zero waste.

“We make our own compost tea – we’re using worm compost as well as our food waste compost and brewing that on-site,” he explains. There was a fair amount of work getting the systems in place, but brewing the compost tea is a pretty straightforward process, he reports.

“We don’t use any heating elements; we fill up our container with about 250 gallons of water and add 10 pounds of both [food waste] compost and worm compost. We have a bubbling system that provides a column of air that goes up through the water to provide aeration, and then we just let it brew for about 54 hours,” Heptig explains.

Initially, there were issues with spray nozzles clogging, but now cheesecloth is used to help filter the compost products, which has helped to prevent clogs.

The compost tea program began on an experimental basis, with half of the putting green being treated with the foliar spray and the other half receiving no foliar apps.

“We did that for about four months, and just from visual inspection we had more root mass and length of roots than we had with the regular fertility program we were using,” Heptig states.

“There’s a lot of information out there that [says] with compost tea you can reduce your water use by 10 percent, and reduce or eliminate your pesticide usage. We haven’t been able to see that yet,” he reports, but notes that in the last few years there has been a lot of extreme weather that has made it difficult to quantify the results. Heptig adds that there have also been some anomalies as far as the results of the applications; for example, on a couple occasions the compost tea seems to have severely dried out the top few inches of the soil profile. He’s been unable to get an answer as to why or how that’s happened, and most of the applications have gone off without a hitch.

In general, the compost tea is applied about every two weeks, but that’s dependent on how often the brewing is done.

“We’ve probably been averaging about once a month lately,” Heptig says. In addition to the compost tea, he uses foliar products from two industry manufacturers. In addition, some other products are mixed in-house – a bag of fertilizer with some blackstrap molasses, for example.

Pebble Beach Golf Links | Pebble Beach, Calif.

About 95 percent of all of our feeding on the greens is now coming via foliar feeding,” says Chris Dalhamer, golf course superintendent at Pebble Beach Golf Links. He uses the foliar to address nitrogen, phosphorus, potassium and other plant needs, while selective granular applications are still used to address soil needs, such as calcium or magnesium.

Dalhamer says the frequency and rate of foliar applications is dependent on the season and weather. “During our growing season, we’re out about every 10 to 14 days; in the winter, that goes closer to 14 days. Then there’s times of year that if the plant needs it we’ll go seven to 10 days,” he explains. “Mother Nature plays a big role in that decision-making process.”

For example, if there’s a hot spell and the turf is under stress and needs to grow, he might apply a little more foliar. During periods of rainy weather in the winter, the window might be stretched and nothing is applied for a couple weeks, Dalhamer says.

Pebble Beach does tissue tests three to four times during the peak growing season to better quantify what the turf needs, but a lot of it comes down to “the eyeball test,” he states. “You’re out there, in tune with your clippings and seeing what things look like and listening to the plant, so to speak.”

All foliar applications are made in the early morning, right after greens are mowed, which allows time for absorption throughout the day and negates the need to go out later on when the course is busy and the winds pick up. Pebble Beach uses a three-wheeled, walk-behind sprayer for its foliar applications.

Dalhamer says these offer the advantage of being more maneuverable than ride-on sprayers, especially on smaller putting surfaces and where bunkers are close by.

“They’re also very light and [there’s] no impact on the greens,” he notes. “It can also be more precise because the operator is looking right at the sprayer, so if there’s a clogged nozzle, you can stop right away.”

Dalhamer uses a variety of foliar products (sometimes mixed with wetting agents and plant growth regulators), with an emphasis on short-chain nitrogen sources, which help him achieve his overall objectives.

“The whole idea of foliar feeding is to give you a controlled response; you know you’re going to get a certain, specific result. You’re not peaking it up with a whole flush of growth, but you’re also not leaning it out. You’re just spoon-feeding exactly what the plant needs. If it’s just the right amount, then nothing goes to waste.”

This level of control and consistency makes it easier to manage the playability of the greens, and it’s also better for the overall health of the turf plant, he points out.

“If you’ve got a healthier plant, it’s better able to withstand disease and other cultural practices that we may do,” Dalhamer states. “There’s just a wide variety of reasons that small dosages to keep the plant healthy is advantageous for a putting surface.”