Christopher Currey

Departments - Three Questions

The Iowa State professor discusses his current research projects and how he hopes to help growers solve different problems in the greenhouse.

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April 24, 2019

Photo courtesy of Christopher J. Currey

Greenhouse Management: How do you approach research and what type of results are you typically looking for?

Christopher Currey: I like to use what I call a shotgun experiment, like figure out the response of 12 different herbs to all these nutrients or a dozen herbs to temperature or two dozen floriculture crops to reduce phosphorus. It’s not the most highly detailed work, but it’s trying to get an impression of how modifying our crop culture or environment can change production, so that’s why I like to have these big swings at things. I’m not necessarily figuring out what phosphorus molecules are doing in this specific plant on this specific cellular level, but I want to figure out how plants respond to low phosphorus.

GM: One project you are currently working on is determining nutrient concentrations for hydroponics solutions for specialty leafy greens. Is this a research area that is still being fleshed out?

CC: There’s not been a lot of baseline data. If you go from no fertilizer to nuclear amounts of fertilizer and you draw a curve, it’ll go up until you hit the optimal and then it’d start to get too much fertilizer or too much of anything. It starts to go down. I usually like to try and find the optimal [amount], to find what maximizes growth. The other thing that you can do in modeling is you can find out the minimum amount of nutrients needed to get an acceptable quality product. Right now, we’ve been chasing down magnesium and calcium because we’re trying to figure out if these greens are heavy-seeding crops — meaning they don’t even need a lot of fertilizer or if we’re seeing certain better responses under higher concentrations just because of one or two nutrients.

GM: Another project you are working on is phosphorus restriction. Where did the idea for this research come from, and what are the benefits of phosphorus restriction for growers?

CC: It’s in in conjunction with Brian Whipker from North Carolina State. He started doing some phosphorus reduction work and he did a really nice job with one of his master’s students, Josh Henry. I really like doing PGR work and that includes non-chemical PGR. So when I saw Brian’s stuff, I was just a fan. But I’m very, very keen on phosphorus restriction for a couple of reasons. One, when it works, you can use a non-chemical growth regulator, which is, I think, always a desirable thing. And I’ve got nothing wrong with chemical PGRs, but I like having non-chemical options. The other thing is some experiments, when you apply a treatment and there is no difference between your different treatments, you get kind of bummed out, like, ‘Oh, nothing happened.’ But if you think about it, if you’re growing a plant with zero to 50 parts per million phosphorus and there’s no difference. That’s huge good news because why would we keep on feeding it 40, 50, 60 parts per million if you don’t get any additional growth or plants that are grown with five parts per million look the exact same because we’re reducing phosphorus use.