Submitted Photo The Kratky method is a simple, low-maintenance way to grow plants hydroponically, meaning without soil. The method works best for fast-growing plants like lettuce, spinach and herbs. (NDSU photo)

Last summer I had an amazing opportunity to attend the National Urban Extension Leadership conference in Nashville, Tennessee. During the conference, I listened to a group talk about how they hydroponically grew lettuce in a gallon jug.

Immediately, I thought this was something I needed to try back home in North Dakota. I mean, growing lettuce in the middle of winter without needing a huge hydroponic tower? Count me in!

So, how do you build this hydroponic system?

Start with a gallon container or similar-sized container; make sure the container you choose can hold a two-inch net pod. A net pod is a small mesh-like container used to hold plants and growing medium in a hydroponic structure. Fill the container with water and add the appropriate amount of nutrient solution, or fertilizer designed specifically for hydroponics. Follow the product label for the correct amount of nutrient solution to add; more is not better.

Next, wrap the container in aluminum foil to prevent algae growth in the water. Place a rockwool cube into the net pod, and then the hydroponic seed variety. Rockwool is used as a medium to support the seed as it starts to germinate and grow. Set the net pod into your water container, then place it in a window with a bright light or under a grow light and wait for the harvest. That’s it!

How does this method of growing work? Based on the Kratky method developed by B.A. Kratky at the University of Hawaii, this method uses capillary action to grow plants without requiring a high-tech system. Capillary action is the movement of water from the roots to the leaves through straw-like plant tissue called xylem. The nutrients in the water are taken up by the plant roots allowing the plant to grow without soil. As the roots take up the water, they grow longer to reach the lowering water level. The lower water level creates an air gap, allowing the plant to receive more oxygen. Just as gaps in the soil provide oxygen to the plants.

Maybe you are thinking, “What can I grow using this method?” Well, just about anything! I grew a variety of butter lettuce from some extra seeds that I had. Other popular hydroponic crops include cucumbers, tomatoes, lettuce and other greens like kale and Swiss chard, and herbs such as basil.

When deciding what to grow, be sure to select a hydroponic seed variety. These seeds have been specially cultivated to perform well in hydroponic systems. Also, make sure that the container you use is big enough for the crop that you are growing. Lettuce is great for gallon-sized containers because it does not get too large. Other crops, like herbs, can be grown in glass jars; however, bigger crops, such as tomatoes and cucumbers, should be grown in a five-gallon bucket or similar-sized container.

Water you going to grow?