Professor Produce

Q: “I noticed that the Wedge has local tomatoes even in the winter, and I was wondering,
how is that possible?” – Janet, Minneapolis

Thank you for the excellent question. I can see how it would be a bit puzzling to see tomatoes in the produce section
advertised as local, while outside it’s down-parka season! But I can assure you there’s been no mistake. We do have
tomatoes grown right here in Minnesota all winter long, thanks to the wonders of hydroponics!

If you aren’t sure what that is, here’s a quick crash course: hydroponic agriculture is the process of growing plants in
a water-nutrient solution instead of soil. I know, how can plants grow without soil?! Very well it turns out, if you do
it right. Plants need a certain combination of nutrients to survive-17 in total. Some of these come from water and air,
like carbon, hydrogen and oxygen. The rest get absorbed through the plants’ root systems-things like nitrogen, phosphorus
and potassium. In traditional agriculture, these nutrients are supplied via synthetic
fertilizers, whereas in organic farming, they come from compost and cover crops. Hydroponics operates on the notion that
instead of adding nutrients to the soil, they go directly to the plants instead, with no middleman.

So what does this type of farming look like? Imagine greenhouses filled with rows and rows of long tubes (similar to
drain gutters on a house). Each one is connected back to a pump that creates a steady, slowmoving stream of water
that has been mixed with a precisely concocted cocktail of essential nutrients. This flows around the plants, which
are suspended in the upper part of the tube above, and bathes their roots with all the food and water they need to grow.

Because it’s a closed system, the exact amount of nutrients, water and light are all tightly controlled and there is
little effort needed on the part of the plant to survive. Which means they grow fast! Much faster than they would
outside. And they can grow year-round. At the Wedge we not only get tomatoes from our hydroponic growers, we
also get basil, lettuces, and microgreens. Look for Tomato King and Living Waters produce at the Wedge if you want
fresh product grown locally even in the middle of winter.

Now Janet, you may notice that some of these growers are not certified organic, but I must tell you, that’s pretty
common when it comes to hydroponics. That’s because most of the qualifications to get an organic certification concern
soil quality, something hydroponics doesn’t deal with at all! And while the USDA has made some modifications for
hydroponic farms, navigating that process gets pretty complicated for hydro growers, and many choose to remain
uncertified because of those obstacles. But that doesn’t mean they’re spraying chemicals willy nilly in their
greenhouses. It just means they feel confident that they are growing healthful, delicious food, even without a
certification. If you want to know more specifics about the growing operations of any of our local partners,
don’t be afraid to ask a friendly Produce staff person. He or she will be happy to help you understand exactly what’s
inside that juicy January tomato.

Send your own probing produce ponderings to the one and only Professor of Produce, at