As you probably know, hydroponics is the art of raising plants without soil. In hydroponics, plants are grown in water that is enriched with the various nutrients that they need to thrive. This article explains a style of hydroponic growing called nutrient film technique, or NFT. I will explain just how easy it is to grow hydroponically and address a few common misconceptions about the method.
Sometimes I think people feel that it’s necessary to have a degree in chemistry in order to grow plants without soil. This is not the case. With today’s hydroponic fertilizers, all of the guess work and calculations have been taken care of for you. You can simply mix and grow and by choosing a complete fertilizer, there is no blending. You simply measure out the proper amount of fertilizer concentrate based on your stock tank volume and you are up and growing. Since you’re recycling the nutrient solution, you actually use much less water and fertilizer than you do in traditional growing. This makes hydroponic growing not only cost effective, but sustainable as well.
Besides your fertilizer levels, which are already proportioned for you, the only chemistry you really need to consider with hydroponics is managing the pH of your nutrient solution. pH is a measure of how acidic or basic your water is and is measured on a scale of 0 to 14, with 7 being neutral. Below 7 is considered acidic and above 7 is considered basic. Most plants thrive at a slightly acidic pH between 5.8 and 6.2. In this range, they are able to best utilize the available nutrients. This can be measured using a handheld, digital pH meter or litmus paper. At our technology center in Dyersville, IA, the water we use for our hydroponic systems comes out of the tap with a pH of 8.0. This is too basic for the plants and needs to be lowered. We use a diluted sulphuric acid to lower the pH of our water, but you can also use vinegar or citric acid. If the pH of your water is too acidic, you can use baking soda to increase the pH and make it more basic. There are also pH up and pH down solutions available that you can try. The bottom line is that if you can maintain a good pH, you are going to have hydroponic success.
Growing with NFT hydroponics really is as easy as one, two, three. All you need is a space to put the system, a little know-how and a few supplies and you are good to grow.
The first component is your water supply. You will need a stock tank and circulation pump. Common tank sizes for small-scale production are 50 or 100-gallon tanks. You can use a smaller tank, but the larger the volume of water you use, the fewer fluctuations you will have with your solution’s pH, temperature and fertilizer level. It is also recommended to have an aeration system in your stock tank to prevent algae. A circulation pump supplies the water to the NFT channels. The water should flow about 1/8” deep down the channels at a rate of four cups per minute.
The second component of a nutrient film technique system are the channels and the frame that holds them in place. NFT channels are supplied with a constant trickle of water at one end, sloping toward the other end where the excess water drains. The nutrient-rich water creates a thin “film” along the bottom of the channel where your plants’ roots are constantly bathed. The beautiful thing about NFT hydroponic production is that these systems can be customized to work well in almost any area so you can grow healthy produce all year round.
The third and final component of your NFT production is the seedlings. We start our seeds in rockwool cubes. These little cubes have great water and nutrient-holding capacity, while providing good aeration. The “mini” cubes that we use come pre-formed in a sheet of 98 that fits perfectly in a standard 1020 flat. For lettuce, kale, spinach, swiss chard, basil and other leafy greens, we start our seeds in the mini cubes and grow them for about two weeks. Good root growth coming out of the bottom of the cube means you are ready to transplant your seedlings into the NFT system. For lettuce, the seedlings will be in the channels for another four weeks or so until harvest. This will vary slightly depending on variety and season.
While NFT production is most commonly used to grow lettuce and other leafy greens, you can grow a wide variety of crops. Tomatoes, cucumbers, peppers and green beans are a few that we have grown quite successfully. However, in order to grow fruiting crops in an NFT system, you will need a deeper channel to accommodate the larger root mass of these crops and a fertilizer blend geared towards fruiting crops. If you choose to grow fruiting crops, you will also need to use supplemental lighting to keep them fruiting in the winter. You need more than 12 hours of light per day to induce flowering and fruit production, but 16 hours is optimal.
I hear this statement a lot: “But hydroponic vegetables just don’t taste as good.” I beg to differ! Not only is the shelf life far superior, the flavor is as well. The improvements in fertilizer programs since hydroponic vegetable production began have made a huge difference in the quality of the vegetables produced. Early fertilizers that were used in hydroponic vegetable production were not as advanced as they are today, which may have contributed to lack of flavor years ago. Growing hydroponically also eliminates the need for pesticides and harmful chemicals, so you are producing the most pure and clean vegetables possible. Don’t let that one bland encounter you may have had keep you from experiencing today’s great tasting hydroponic produce.
By utilizing an NFT hydroponic system to grow, you are eliminating variables that affect the yield and quality of plants grown in soil. Plants grown in soil are affected by the unpredictability of the climate, such as too much or too little rain or extreme temperatures. With NFT hydroponics you can optimize your overall production and ultimately, your harvest quality. Growing with an NFT hydroponic system will result in higher yields in significantly less time compared to soil growing. It sounds too good to be true, but it’s not. It’s NFT hydroponics!
Another exciting and sustainable way that we have been using NFT hydroponics is with our Fodder-Pro 2.0 Feed Systems. These systems are gaining notoriety as a cost-effective way to feed livestock with sprouted grasses and grain. Feeding hydroponically sprouted fodder to livestock instead of field-grown hay condenses what would take acres to grow into a few hundred square feet. Fodder systems are also becoming increasingly popular for growing microgreens. Microgreens are culinary herbs, edible flowers, baby lettuces or specialty greens that grow quickly and are big on flavor. These greens are in high demand, especially in the high-end restaurant business and can fetch a premium or make a great addition to your own salads. Another type of sprout that is really exciting is grasses, such as barley or wheat, used for juicing. If you haven’t heard of juiced grass yet, you will soon. The amazing nutritional and healing properties that these juiced grasses contain are currently being studied.
NFT hydroponics is a clean, nutritious, sustainable way to grow a wide variety of produce. Don’t have quality soil for gardening where you are? Or maybe you just want to grow fresh produce year round and old man winter thinks otherwise? You don’t need to be a chemist or mathematician, you just need to have an open mind and not be afraid to try something new.
Sam Shroyer has a bachelor’s degree in horticulture from South Dakota State University and 20 years of horticultural experience, it is his goal to “re-teach” the public that sustainability and self-sufficiency is well within everyone’s reach.