Seeking substrate

As CEA operations get bigger and more sophisticated, the industry demands ever more of the share of growing media available on the market. But what happens when the common backbone of nearly all growing media starts to become difficult to source?

“We’re relying on peat, and there is no better growing media out there than peat,” says Jeb Fields, Louisiana State University Ag Center associate professor and extension specialist. “But there’s only so much peat that can come out of the ground, especially here in North America.”

Fields explains that several factors have limited the peat supply: longer rainy seasons in the north, increased demand as new industries like cannabis and CEA food production boom, and strict control by North American governments and associations.

More growers than ever are concerned about the availability of their growing media. And even though scarcity adds stress to growers, it also drives changes in behavior that may turn out to be beneficial in the long run. See how growers responded to our survey earlier this year.

In 2024, more growers said that they were purchasing standard mixes from manufacturers and using a combination of in-house blends and manufactured mixes. Meanwhile, there was a reported drop in those purchasing custom mixes or mixing their own.

“I think this is out of necessity. During shortages, we buy more of the premium products because those are more available,” says Fields.

Fields offers that he’s spoken with growers who have mixing lines that haven’t been used at all this year. “They say, ‘What we could buy was already pre-made.’ So there’s no point in running them.”

But there are still mixing lines in use, according to the data. Of those who do mix their own, more respondents made that choice based on better control over the mix and the need for a variety of mixes to fit their crops rather than those who did so to keep costs low.

And while consistency and quality of pre-mixed media lead purchasing decisions, convenience and cost round out the top three reasons for buying from manufacturers.

Changes in desired ingredients are likely a necessity during a period of scarcity. The issue is so pressing that nearly three-quarters of respondents have changed their growing media formulation in the last two years because of lack of availability.

It’s clear that in 2024, growers are feeling a supply crunch. The most important attribute in a substrate is availability, followed by consistency and cost. Performance, which was the most sought-after quality in 2023, fell to fourth, above sustainability (fifth) and technical support (sixth).

Likely due to factors of availability, businesses are using a mix of sources rather than only buying direct from manufacturers or regional distributors. In fact, the number of growers using this tactic doubled since 2023, and the number of those reporting buying direct from distributors has halved.

Grower warehouse inventory is also growing scarcer. In the last year, there was a 20% drop in those holding extra substrate inventory and an equivalent increase in those taking just-in-time delivery.

Patrick Alan Coleman is editor of Produce Grower magazine. Contact him at pcoleman@gie.net.