Find your fertilizer balance

Features - Production

Plant nutrition experts weigh in about how to create — or readjust — your nutrition program to maximize your crops’ potential and minimize product loss.

February 24, 2016

Fred Hulme, director of technical services at ICL Specialty Fertilizers, says that growers should take a systems approach when crafting a nutrition program. Analyze the nutrients in your overall operation, then make tweaks to specific plants as needed.
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To talk fertilizer and nutrient solutions, we called on Fred Hulme, director of technical services at ICL Specialty Fertilizers, and Shiv Reddy, technical specialist at Sungro Horticulture, to lend their advice about how to create (or improve) your plant nutrition program.

Test your resources

If you’re developing a nutrition program, it’s good to test the water and growing media in your own facility, both experts advise. Reddy says that some fertilizer companies offer a free water analysis, and can then offer up recommendations.

Conducting routine testing can also help you quickly reference which nutrient program worked well, and which didn’t, says Hulme. “If you were doing testing and doing a cross journal and logging, you would know from previous years that the crops might have some issues,” he says. “A grower should have a periodic check of EC and pH, and health. There are a variety of ways you can [test].” One way, Hulme says, is to take soil samples or tissue samples and send them into a commercial lab once per year, which costs more, but will yield much more information regarding your crop. Right about now would be a good time to send samples to a lab, he says, to “get your handle before your crops start actively growing.”

Growers should also conduct weekly tests with inexpensive handheld meters to spot-check with, while also visually scouting.

After you’ve tested, keep testing

Reddy says that more established growers can sometimes get away from testing their water and growing media when their plants are doing well and everything is going according to plan. But he advises to “keep testing for that EC and pH the whole time. That way, you can quicker spot a problem.”

After growers do discover and correct a problem, it’s important to continue to test the crop, and not fall back into a routine of failing to regularly check for that nutrition deficiency or surplus. “After the problem happens, [the grower and I] both think, ‘Oh, I wish I had tested it and caught it,’” Reddy says.

Use a systems approach

Because growers often have many different crops growing in the greenhouse at given time, it’s best to find a one-size-fits-all program after you’ve discovered the components (or parameters) of your irrigation water and growing media, and then “special treat the finicky crops with special mixes or fertilizer supplements,” Hulme says.

For example, “A lot of vegetative [plants] tend to have a higher demand for iron,” he says. “At the same time, you have some geraniums or marigolds that have a sensitivity to iron. So you can’t really design one feed program that’s going to fit everything. What you should do is aim for the lower-demanding crop, like your iron levels for your geraniums, and then supplement the iron for petunias and calibrachoa,” by spot-checking with sprays or drenches with only iron, he says.

After the problem happens, [the grower and I] both think, ‘Oh, I wish I had tested it and caught it.’” — Shiv Reddy, technical specialist at Sungro Horticulture

Read the label

Hulme says not reading the back label properly is one of the biggest mistakes he regularly sees with growers. “There might be a crop name on the bag, and really, you need to look at the nutrients [on the back of the bag],” he says. “It takes a little bit of scrutiny … But if you consult with your fertilizer support person, you probably can select a better nutritional option based on what you need to add.”

Log information regularly

“It’s kind of an old-timey practice, but it’s a good practice,” Hulme says. He advises growers to document dates, what nutrient they adjusted for, along with the crop’s response to that treatment, to better reference that information in the future. “It’s all about consistency,” he says. “You still have environment and things you can’t control, but to an extent, you can. You can make some improvements based on observations instead of just making changes willy-nilly.”

Call on your resources

Keeping in contact with local extension office, your fertilizer support specialist and even other growers you’ve networked with is a good practice, in case a difficult nutrition program ever arises, both experts agree. Reddy suggests keeping in contact with your provider, especially, throughout the season to see if any changes are required during the time your crop is growing.