After covering all things hydroponics over the span of a couple weeks, what's left? NFT and aeroponics baby, that's what! NFT, short for Nutrient Film Technique, is a popular hydroponics application commonly used in greenhouse application. Although NFT systems may greatly differ in appearance depending on the scale of the application, the general concept remains the same as all hydroponic applications. A NFT system consists of a chamber, or series of chambers, constructed of gutters or PVC pipe. If gutters are used, a cover is often used to block out the light from above, preventing the roots from being exposed. Holes are drilled in the covers or pipe to accommodate the round, net baskets used to house the base of the plant. Net baskets come in a variety of sizes, some which include 2, 3, 3.75, 5, and 6 inch round. Square net pots are also available in a variety of sizes, but are often referred to as pond baskets. In either case, the walls and bottom of the net containers are made of a rigid, plastic mesh material. A net pot acts as an anchor or foundation for the plant. The roots grow through the mesh, thus enabling a plant to hold onto the walls of the basket and stand upright. Unlike a plant growing in a container of soil, the plant's root system is not restricted to the container. The roots grow through the mesh and down the growth chamber. The chamber needs to be deep enough to allow an inch or two of airspace between the bottom of the net pot and the bottom of the growth chamber. The next question is how deep should the layer of nutrient be. Most of the time, the depth of the nutrient solution should be no more than a trickle, as thin of a layer as possible. But, as in all aspects of life, there are exceptions to the rules. A seedling or freshly rooted cutting has a small root system that would not be able to reach the thin layer of nutrient solution flowing along the bottom of the chamber. Your plants will work as hard as they can to reach the bottom of the growth chamber, but that takes days. In times like these, occurring in the beginning of your growth cycle, you need to raise the level of nutrient solution so the bottoms of the net pots sit about 1/8 of an inch in the solution. Now let's take a couple steps back. We are talking NFT. We have a growth chamber. Nutrients are pumped in at one end of the growth chamber, which needs to be at the higher end of a slight incline. Nutrients flow down the entire length of the growth chamber with plants happily nestled up top with the roots basking in the nutrient solution. Nutrients run down to the drain. If the drain is flush with the bottom of the chamber at the drain, you have a thin layer of nutrients my friends, which is ideal most of the time. At those times you need to raise that level, risers need to be applied. This usually calls for a drain with adjustable risers, or a grommet fitted with a PVC pipe. More risers or PVC pipe exposed means more water in the growth chamber. Over the course of a week or so of the new plants being introduced into the NFT system, you want to monitor the plants root growth and lower the solution to accommodate the root development. Stay ahead of those roots. Make them work for food by keeping the level of nutrients in the chamber a quarter inch under the root mass until the nutrient level is down to a very thin layer, then let those babies soak it up. Now, as great as that system sounds, I've found that there is a flaw to the NFT design. That goes back to the golden rule of hydroponics; roots sitting in water will rot. The exceptions being aquatic plants, of course. Browning roots, fungus gnats, and pythium will challenge you if your roots are waterlogged. In comes aeroponics, the answer to our problems. Yes, I'm throwing another term at you. I know you're up for it. I'm running out of space so I'll keep this short and sweet. You have a growth chamber, much like what we just got done talking about with NFT. Instead of a nutrient layer flowing along the bottom of the chamber, you have a water line attached to a pump sitting in a reservoir like NFT. The water line runs down the center or circles the chamber. Misters are tapped into the water line and the pump is plugged in. From the outside, it may look like any other hydro system. But on the inside of those chambers are sprinklers loving those root systems. It rains everyday in your aeroponics system. Don't think I'm just brushing over a topic as important as aeroponics because that couldn't be further from the truth. Aeroponics just happens to be my favorite method of gardening and we will be spending plenty of time on it in the near future. Pat yourself on the back if you've been paying attention. We've gotten through most of the popular methods of hydroponic gardening. So what comes next? Well, there's only lights, nutrients, vegetable crops, tropical plants, ventilation, greenhouse applications, even aquaponics! That's what I'm talking about, or writing about. Be here next week! |