A fresh look at growing media

While media may be an old topic, there are new aspects to consider for this season and beyond.

The buzz in the industry centers around the peat moss shortage hitting the market.

“Any time you have a shortage, it will affect what’s going on and even costs,” says Rick Vetanovetz, manager of technical services in the Eastern region for Sun Gro Horticulture. “I’m speaking for a lot of different manufacturers, but when you have a poor harvest in one area, you have to rely on another area for supply of that material, and when you do that, it disrupts a lot of things.”

For instance, you have to start moving material longer distances. In the case of Sun Gro, they’ve seen a shortage in the far East in areas like New Brunswick and Quebec. But on the flip side, they’ve had a great harvest in Manitoba, but that means now they’re trying to service all their customers out of that area.

“You’ve got these dynamics occurring, and it puts a strain on any company,” he says.

It increases costs to ship, and, in the grand scheme, there is less overall product.

“It gets tricky when that occurs,” Vetanovetz says. “Often times, people will say, ‘Oh, they say that, but they always have it available.’ They don’t know what the suppliers are doing behind the scenes to make sure all their customers are getting supplied.”

In some cases, suppliers are purchasing peat from the outside to make up for their shortages.

“When you do that, it increases costs as well,” he says. “The bottom line for the industry is they want to make sure that all their customers are being serviced – that’s the bottom line. If you don’t service your customer, you’re going to lose them. Everyone is interested in making sure [proper service] occurs.”

With the shortage, you may be exploring other options for media due to increased costs.

“The peat shortage is driving demands, whether it be bark or peat from worldwide sources, and it’s causing growers to look outside of just using their standard mixes in terms of what other component can they add to give them benefits in propagation, production or on a retail bench,” says John Bonin, manager of business development and sales, Northeast U.S., for Jiffy Products.

If you decide to try new mixes, it’s important that you collect good data to make informed decisions in the first year of trying new products or mixes.

“I encourage growers to look at trials side by side in similar crops or same crops throughout production, and I really think, ultimately, it comes down to careful attention, monitoring the product and being prepared to, even in the trial phase, handle that product or material a little bit differently,” Bonin says.

He also says that whether you’re using different types of peat or amendments in the mix, you should be able to adjust.

“[A grower] should be able to look at the assessment of his crop as it’s growing and be able to adjust either his water or his fertility practices as he sees the crop growing,” Bonin says. “It’s not, ‘I’ve always done it this way, this is how I’m going to continue to do it,’ because each component does behave a little bit differently based on percentages within the mix.”

Ideally you should monitor on a seven- to 10-day basis, and if you don’t have the staff to be able to do that in-house, you should have an external lab handle it.

The other big issue you may face is determining how much media to purchase.

“It’s important to growers that when they purchase the products, they have a good idea of what they’re going to use in the season and not overbuy,” says Ed Bloodnick, director of grower services for Premier Tech Horticulture. “They can buy product, and they may say, ‘If I buy a little extra, I’ll get a better deal.’

It may look good on paper, but in the long run, it means extra management later because the product isn’t as effective as a fresh product.”

That’s because if the produce contains a starter charge, microbes that are found naturally in the organic component of the growing media can drawdown the Nitrogen contnet.

“When it’s carried over from one season, it can still be used, but it’s not the same freshness,” Bloodnick says. “Maybe it’s antiquated now, but it’s like film – you used to buy film and it’d say best by certain date. The film is still good, but it’s not the same when you take a picture with it [after the date]. Growing media is the same thing.”

If you’re using season-old media, you plan to buy extra to save on costs, or you already have bought extra, keep in mind what you’ll need to do in order to get a similar performance to fresh media.

To start, you need to know how to store it properly.

“Storage has a big impact on all of this,” Bloodnick says. “If it’s stored in cold conditions or cool or out of light, those are less likely you’ll see some changes in the product.”

You’ll also want to check it when you’re ready to use it.

“Best practices would be to, if you have product that’s left over, have it tested by a laboratory or the manufacturer to know what you’re starting with in terms of pH, EC and nutrient content,” Bloodnick says.

This is recommended for peat-based media more than nine months old, and bark- or coir-based media more than six months old. In warmer areas, monitor sooner, as high temperatures have a greater impact. Many growers will mix it with new media, but that’s not recommended.

“For a grower, it’s better not to mix it but to treat it separately,” he says. “If you plant trays with fresh mix versus a mix that’s a year old, there’s going to be a difference in how that plant grows versus if you water it untreated.

The best way to correct any imbalances from age is to fertilize immediately after transplanting. Apply water-soluable fertilizer in small amounts, about 75-100 ppm of Nitrogen for general purpose growing media and 25-50 ppm of Nitrogen for plug/germination media. This can bring it back up to a starter charge level.

Ultimately, you need media to grow your products, so make sure to run the numbers, trial new products and use the data from these two processes to make the best decisions for your greenhouse operations.