Finding the right mix

2017 State of the Growing Media - Choosing growing media

Three growers explain what goes into their growing media, how they select it and more.

June 1, 2017

Michael's Greenhouse in Connecticut is trialing a new mix in hopes of increasing water retention and reducing shrink in plants shipped to big box stores.
Photo courtesy of Michael's Greenhouses

Every grower faces different problems when it comes to growing media. Some are focused on maximizing the shelf life of their products. Others work to determine and manage cost, while others are more concerned what mix is best for the season.

Below, three growers explain what goes into picking the right growing media for their business.

Michael’s Greenhouses

With a business centered around annuals, perennials and holiday crops, Michael’s Greenhouses in Cheshire, Connecticut, has been in business since 1963. It’s only been in the last year that the business has made changes to its growing media.

“We have in the past only used one [growing media mix],” says Michael’s general manager Patrick Herzing. “Recently, we’ve been making some amendments to that.”

According to Herzing, who has been with Michael’s since 2009, the grower is currently trialing a second growing mix on annuals and perrennials in hopes of finding a mix with better water retention. The trial started after plants they were shipping to big box stores like Home Depot were affected by shrink because the plants could not go a day without watering.

Michael’s current mix is 90 percent peat and 10 percent perlite with starter fertilizer, a wetting agent and a plant nutrient added in. Until the trial, the only change from the 90-10 was an 80-20 mix with the same components.

In their trials, Michael’s uses HydraFiber, which is designed to allow growing media to retain more water. So far, Herzing has been pleased with the results. They plan to trial it with mums before fully committing to the new mix.

A key, though, is not to change the growing media altogether, but enhance it. Herzing says the peat and perlite mix he currently uses is versatile.

“We can grow pretty much anything in it,” Herzing says.

All growers face decisions about their growing media that depend on the size of the operation, plants needs and more.
Photo courtesy of Michael's Greenhouses

Buffalo-berry Farm

Buffalo-berry Farm, a native and bedding plants grower based in McCall, Idaho, near the mountains in the central part of the state, has 10,000 square feet of growing space outside, but also has 4,000 square feet of greenhouse space. The mix they use inside is a combination of peat, perlite and vermiculite and designed specifically for growers in the Pacific Northwest.

In-house, they incorporate dipson, dolomite and mycorrhizae into their mix. Until last year, they also added compost to their mix. But a bad experience with compost moved them away from using it after 20 years.

“We had good experiences with it and we liked incorporating some organic matter,” says owner Margo Conitz. “[Fast forward one year, and we were not still 100 percent sure [why our mix went bad]. We got a new truckload of the compost we’ve been using for 20 years from the same company. But with this stuff, we started some discoloration and uneven germination. And then we started seeing stunted growth. It took us a year to figure out that it was the compost.”

In the future, Conitz says Buffalo-berry would like to be more environmentally friendly and conscious with their growing media by sourcing it only from sustainable, renewable sources.

Granby’s Greenhouse

With six acres of indoor growing space, Granby’s Greenhouse in Verona, Illinois, is built around wholesaling crops like celosias, mums and bedding plants. As a result, deciding what growing media works best for the business is based around one simple benchmark.

“Performance,” owner Greg Granby says when asked what goes into selecting the right mixes. Currently, Granby’s has three different mixes: a germination mix, a spring mix and a fall mix.

When selecting a new mix, Granby’s has a rigid vetting process that has been developed over the 50 years the operation has been open and is aided by Greg’s previous experience working at a growing mix facility. It’s a lot of trial and error and adjusting small aspects of the growing media, says Granby, and no significant alterations are made without proof that the change is good.

“We go with a trial, then full scale, and then eventually, replace,” Granby says. Among the current rotation of mixes, the germination mix has been around for five years, the spring mix for four years and the current fall mix is in its second year after small adjustments were made to the previous version. Both the summer and fall mixes are custom-made.

“The plant needs [require it],” Granby says of using a custom mix. “Here, where we are in the Midwest, we could have a real dry summer or a real wet summer. If we have a real wet summer, I need a mix that will drain and dry out because they need a break from being watered all the time. So, we’d use a real porous, fibrous mix.” The current fall mix is made of peat, perlite and ground-up stems and twigs.

For now, Granby doesn’t see any of the mixes that are currently in use changing in the near future. And that’s good for plant performance.