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Hydroponics can provide gardeners with a fun winter diversion

Editor's note: This is the second article in a three-part series about growing plants indoors, from Becker County Master Gardener Nicholas Williams. The Master Gardeners are part of the University of Minnesota Extension.

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Greenhouses can easily be adapted for hydroponic gardening. (Submitted photo)
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Hydroponics is a method for growing plants, either indoors or outdoors, without dirt. Plants are germinated in a supporting medium that will allow the roots to develop and support the plant; nutrients are provided by bathing the supporting medium in a solution of water and nutrient chemicals.

The first question one may ask is, “Why do this?" There is no good answer for that; plants grow just fine in dirt, and the machinery of hydroponics can be intimidating for the neophyte gardener. But if a person wants to try something different or enjoys the science of plant physiology, hydroponics may provide a gardener with a winter diversion as well as some pretty — or even edible — plants.

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In nutrient film technique (NFT) hydroponics, the plants sit in small openings on top of an enclosed channel, also known as a tray, into which nutrient-infused water is pumped continuously. (Submitted photo)

I would recommend a kit for the first attempt at hydroponics, and many are available. I would also suggest using an internet source that specializes in hydroponics rather than a general retailer. Proprietors of these specialty sites are usually excited to help a person start a project and can offer advice along the way. One can spend from $30 to several hundred on a system that would fit in a small room or closet.


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Hydroponic gardens don't need much room in which to flourish, just a readily available light source. (Submitted photo)

I use a large closet lined with what is essentially aluminum foil to reflect light, although hydroponics can be done anywhere if one doesn’t mind the extra light. Kits usually come with either liquid or dry nutrients, to be mixed with water for the feeding solution. The substrate for the plants to germinate and grow in is provided as well. As one gains experience, you can even experiment with various types of substrate and nutrient mixtures.

Lighting is critical, and it would be unrealistic to expect to grow hydroponically indoors without artificial light. LED technology has advanced dramatically in the last decade and the cost of acquiring these lights and using them has dropped significantly. And they do not produce as much heat as the lights that we used years ago. There are even "tunable" lights that emit specific wavelengths that can be changed throughout a plant's life cycle. Light at about 400 to 500 nanometers (nm) appears blue-tinted to humans and stimulates vegetative growth; light at about 620 to 780 nm appears more reddish to humans and when mixed with the lower wavelengths, encourages flowering. Timers are essential and can be used to simulate the lengthening days of the early growing season and the waning hours of light as the growing season ends.

One of the reasons I enjoy hydroponics is because one can experiment with variations on light quality and duration. I once "forgot" to add red light when tomatoes were ready to flower and as a result had 6 of the world’s tallest tomato trees with a total of about three tomatoes. (Of course, if lights come with a kit, they would emit all wavelengths that a plant would ever need and that would appear white to us.)

Nutrient combination products are available that provide every nutrient needed and even buffer the solution to the proper pH, almost guaranteeing success. With experience and a sense of adventure, a person can observe differences in growth and productivity based upon variations in the nutrient solution. Routinely checking pH, checking dissolved solids, and trying various combinations and relative strengths of nutrients and micronutrients has the aura of a chemistry experiment — this may appeal to some. The possibilities are almost limitless. I once produced tomatoes that tasted like grapes because of the addition of grape extract (and some other things) into the nutrient solution. They weren’t very good; I won’t do that again. Purple lettuce is not very appetizing either.

The two most common ways of nutrient delivery are "ebb and flow" and "nutrient film technique." The latter is probably the easiest, and I would recommend that as a first attempt at hydroponics. Almost any plant other than root vegetables can be grown. I once grew tobacco hydroponically and the native elders that used it in a ceremony said it was very good.

We usually have a crop of lettuce and tomatoes going in the basement over the winter months, and simply going downstairs to gather this is a blessing. This is not cost effective. It would probably be cheaper to drive to the store and buy it; it takes time and a bit of work too, but it is a joy to see (artificial) sunlight coming from the hydroponics room in the middle of these dark winters.


The Becker County Master Gardener program is operated by the University of Minnesota Extension.

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