In the backyard brawl of liquid versus granular fertilizers, neutral ground may be the greenest. With so many variables affecting each formula’s effectiveness, and innovation closing the gap between the two, the unbiased approach works best.
Though 90 percent of fertilizer applications are granular at Tomlinson Bomberger Lawn Care, Landscape, and Pest Control in Lancaster, Pa., Ryan Mason says he sees equal pros and cons for each.
“I’m an advocate of both because I’m an advocate of what works,” says the lawn care and plant health application services manager. “We want to make sure we’re doing not only what’s best for the environment, but what’s the best value for clients. Cost is a small part of it, but it’s about great results.”
Both liquid and granular fertilizers deliver results – in certain situations. For every LCO that values the instant-greening power of quick-release liquids, another swears by slow-release granulars.
Remember the homeowner.
Southern Botanical in Dallas sprays predominantly liquid applications throughout the year, finishing with a granular round in the fall to release nutrients slowly through the winter.
“The attractiveness of liquid fertilizer is that plants utilize that much sooner than a granular,” says Jason New, vice president of garden management. “There’s more of an instant impact. So if you’re having issues and you need quick results, a liquid application is what you need.”
Though quicker green-up is appealing to customers, liquid’s strength can also backfire.
“Being that liquid fertilizers are available to the plant more quickly, they cause a surge growth because they’re immediately absorbed,” Mason says, which can cause customers to mow too much, too soon. “If it’s a really quick-release liquid, this thins out the cell walls, which causes the plant to become weaker and more vulnerable to disease outbreaks. Liquid can have a volatile effect on a lawn if not applied properly at the proper time.”
That’s why cultural practices surrounding applications are just as important as the fertilizer itself – which makes customer education key. Mason emphasizes the timing of irrigation and appropriate mowing heights, as well as recycling grass clippings, to maximize results.
Check the temperature.
Weather can botch fertilizer functions, too. Humidity can clump granulars, causing spotty application. Liquids are typically easier to control, but wind can blow droplets off-target and evaporate liquid quickly. New recommends granular in those cases. But when rainstorms loom, he opts for liquids, which won’t be carried away.
If granular stays put long enough, though, it can be just as effective as liquids over longer periods.
“What we like about (granular) is lawns can be fed with less frequency,” Mason says. “It does take more time – which is beneficial when you’re dealing with hot, dry periods where you don’t want to risk burning the lawn. With slow release, the customer’s getting a strong, healthy feeding that’s going to promote a stronger root system over time.”
Of course, the biggest misconception is that all liquids are quick-release and all granulars are gradual. That’s no longer the case, says Paul Gebinine, plant health care manager at Terracare Associates in Littleton, Colo.
“There used to be either a yearlong or an eight-week granular product, and now you can pretty much get any release time you want,” says Gebinine, citing 8, 12, 36, 46 and 60-week options. “Your granular’s going to have a mix of some quick-release and some slow-release in it, so it really doesn’t take long for it to pop.”
The drawback is the mess displaced granules make when they “pop.”
“With granulars, it’s hard to get all that blown off the sidewalks and driveways,” Gebinine says. “Usually, iron is a darker particle that’s mixed in with a fertilizer blend. It’s harder to see when you’re blowing it off – until it rains, and then there’s a rust stain on the customer’s driveway.”
Aside from cleanup, New says granular labor is less complicated, while Mason says liquid is easier to apply evenly. Gebinine sees equal room for application error on either side. “You still have to calibrate everything, either way,” Gebinine says.
Cost can be another factor. Spreaders can run a few hundred dollars, as opposed to several thousand for a spray rig. But consider the overall cost per application.
“The labor and equipment costs can be higher for liquid application, but the material cost is actually much less expensive,” New says. “At first, my big misconception was that liquid applications were more expensive and didn’t last as long, and that granular was less expensive and lasted longer. The reality is: If you have the right people and the right equipment, it costs you less to do liquid applications, and both last equally as long.”
Mason finds liquids cost about 10 to 25 percent less than comparable granular fertilizers – a difference of several dollars per thousand square feet. But the gap is shrinking.
“Granular isn’t that much more expensive anymore,” Mason says. “When I do cost comparisons for the same amount of nitrogen on a lawn with liquid against granular, I’m really not seeing a huge difference anymore. The misconception is that granular is too expensive, but things are changing.”
With costs increasingly comparable, the clincher for Mason and Gebinine becomes volume.
“When you’re doing a lot of square footage with a liquid, you have to have a gigantic truck,” Gebinine says. “You’re going to be filling it constantly, so you have to carry that liquid fertilizer with you in the truck to fill the tank. You can get a lot further with a truckload of granular fertilizer.”
As the differences between liquid and granular fertilizers grow more congruous, it forces LCOs to carefully test the options to understand what works best for local conditions.
“There’s not a perfect recipe for one or the other,” New says. “Sometimes, it’s a perfect recipe for the landscape that you’re working on. It’s very climate-specific, so really it’s knowing your soils and getting a customized program for your area. It doesn’t matter which one you use, as long as you’ve got the right nutrients inside of it.”
The author is a freelance writer based in Cleveland.