RC plant science class grows hydroponic lunchtime lettuce

RAYMOND — Many consumers like the idea of eating produce that was farmed locally and didn’t spend time in a mesh bag in the back of an 18-wheeler.

At Raymond Central High School, students enjoy a salad bar stocked with greens sourced from a classroom a few doors down the hall, and the farmers are their classmates.

In Katie Donahue’s plant science course, students oversee the production of vegetables — from germination to harvest — using a collection of hydroponics towers that the school district purchased in 2021. This school year is the first that the towers have been used extensively, and Donahue started the year by asking the school’s lunch staff if the crops produced in the towers could be used in students’ meals.

“I was like, ‘If we grow lettuce and tomatoes and other vegetables, would you put it out on your salad bar?’” Donahue said. “The head of the lunch department said absolutely.”

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Now, the lettuce grown in an indoor nursery at the school is appearing on lunch trays, and plant science student Aleyna Cuttlers said other kids like the idea of knowing where their food is coming from. As a bonus, the food tastes good.

The class meets two or three times per week, depending on the block schedule’s rotation. And Donahue said the students make the jaunt from the high school’s CTE wing to its science wing — where the nursery receives sunlight through large, south-facing windows — at least once per class period. Sometimes they’re there for 20 minutes, just topping off water supply and mineral nutrients. Other times, they spend the entire 90-minute class block harvesting their crops.

In the nursery, four hydroponics towers are operating, and three sit idle as they wait for new repair parts to arrive. Two have plants growing at the moment — one has small lettuce sproutlings that have taken off in the span of a couple days. The other tower is growing tomatoes, which were planted at the start of the school year.

“Second week of school, we were up here, planting seeds, germinating, getting stuff ready to rock and roll,” Donahue said.

To start the process, seedlings germinate in rockwool cubes, and once they’ve begun to grow, students place the cubes into pockets in the grow towers.

The towers operate on timers that regulate the amount of water and artificial light the plants receive. The lights come on at 6:30 a.m. and turn off at 5 p.m., Donahue says. The water pump kicks on every 45 minutes and runs for 15 minutes, transporting water from a tank at the tower’s base through a tubed path to the top, trickling the water onto the plants from the inside.

“It’s basically like a slow rainfall,” Donahue said.

Four fruits have emerged on the tomato tower so far, and the class expects several dozen more to arrive in the coming weeks. It’s important, too, Donahue said, that the students facilitate pollination by feathering the tomato plants’ leaves.

“There’s no bees or flies or anything in here to do it for us, so we have to do it ourselves,” Donahue said.

The process takes longer for tomatoes than lettuce, but in general, the major advantage of hydroponic growing systems is the speed at which the plants mature, says student Jaelynn Kliment.

“What takes us about a month to grow a head of lettuce to be able to use would take two months in a normal agricultural soil setting,” Kliment said.

Then, once the plants are ready to harvest, they’re removed from the towers, cut and sent down to the cafeteria kitchen, and the lunch staff takes it from there. By all accounts, the students who eat the food are happy with the product.

Kliment said there are limitations to what can be grown using the hydroponics towers — you wouldn’t be able to grow root vegetables like radishes or carrots, for instance. But she said the class has discussed the possibility of growing strawberries, peppers and eggplant.

Aside from the food itself, the students say their new education in water-based horticulture has given them a satisfaction in knowing that their work is having an impact outside the classroom.

“It’s definitely nice knowing that what we’re applying in the classroom and what we’re learning, we can actually use that to feed our school,” Kliment said. “We’re doing something for the school.”

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