2018 State of the Growing Media Research

Cataloging the greenhouse industry’s use of growing media is important to us. We made some changes to our survey this year to better reflect how growers use growing media.

Updates to the survey include questions about controlling pH; as well as additional answer options regarding growing media expenses, types of growing media, use of additives/components, and if growers are purchasing growing media from both a manufacturer and a regional distributor. We also dug into the archives of our State of the Growing Media to analyze the results since 2011. Within these pages, you will find many comparisons with previous years’ research, as well as other insights.

Plus, on page 48, Brian E. Jackson of North Carolina State University provides an overview of selecting and using wood substrates. Then, on page 52, learn about how to conduct a successful growing media trial.

Although our survey is now closed, we’re still interested in learning what you think about the current trends in growing media and how those trends impact your business. Drop us a line at pwilliams@gie.net to share your thoughts!

More respondents are using fewer growing media mixes, with more of them using 1-2 mixes and fewer of them using 3-4 mixes than last year.

This is the highest percentage of respondents who have been using 1-2 mixes since 2014, when that number was 67.4%. This likely indicates that more specific mixes are beginning to meet more grower needs, reducing the need to employ several different ones as in the past.

Although different plants often require different growing mixes, growers have maintained or increased production of several crop types, according to our 2016 and 2017 State of the Industry Reports, so crop selection likely isn’t having a drastic effect on growing media choices throughout the industry. In addition, as indicated by a later question in this survey, fewer growers are facing issues with growing media than last year, so it appears many of them are sticking to the specific mixes that work for them.

More respondents are using combinations of commercial mixes and in-house mixes than last year, and more are preparing their own mixes in-house. Fewer respondents purchased standard mixes from a manufacturer than last year, and fewer bought custom-made mixes from a manufacturer. This year, we added an “Other” option, which yielded additional answers such as purchasing both standard and custom mixes.

This year, we added the answer option of purchasing both direct and from a regional distributor. While the number of respondents who said they buy from a regional distributor decreased 8.8% percent from last year, the number of respondents who said they buy direct decreased 18.7%, suggesting that growers who purchase from both sources may be buying a greater percentage of their product from regional distributors.

This year, we split up the answer option for growers who spend $4,999 or lower on growing media into two separate answer options — $3,000-$4,999 and $2,999 or lower. More respondents spend $2,999 or lower than any other price range.

Compared to last year, the number of respondents who spend in several price ranges above $4,999 remained flat. The market has been relatively stable the past few years, but not all growers are making the large-scale expansions that would lead them to purchase much higher quantities of growing media.

Growers wrote in with some of the other issues that they’ve had with their growing media, including weeds, pests and diseases, wet bags and inconsistent mixing.

Margery Daughtrey, plant pathologist at Cornell University, provides the following insight about how poor care of growing media can cause diseases: “Growing media needs to be handled with great care: One can’t pile it onto a cleaned area of the floor and then walk on the edges of the pile. Shoe soles can bring in lots of Rhizoctonia, Pythium and Fusarium from the outside world. Many of our root-attacking fungi are common soil dwellers.”

Daughtrey also recalls a recent contamination of Thielaviopsis basicola in a peat-based mix. She notes that on some occasions, pathogens appear in growing media, so growers should buy their mixes from a reputable source.

Weeds — one of the issues that growers cited — can lead to pest and disease issues, Lee Stivers, Penn State University extension educator told Greenhouse Management for the November 2017 issue. (Editor’s note: You can read the full article at bit.ly/2wAL596) And when it comes to weed management, it can be difficult to determine the source of weed seed, according to “Top 10 Practical solutions to growing media issues,” a June 2010 Greenhouse Management & Production article by Jamie Gibson, Bob Steinkamp, Michael Tilley and Hugh Poole. (Editor’s note: You can read the full article at bit.ly/2Ihg0c4)

We included several new answer options this year — wood chips, foam, pumice, biochar and clay pebbles. Out of these, wood chips are gaining the most traction. Fill-in answer options include no alternative growing mix components, wood fiber, PittMoss, coconut hulls and sand.

Compost has been on a consistent decline since 2015, when it was at 50.6%. And bark fell back down from its peak usage in 2016 and 2017, when it was at 53.9%, the highest it had been since our growing media survey’s inception in 2011.