Simple Hydroponics

Getting started with hydroponics is often an intimidating endeavor for most gardeners. However, with a simple introduction, most will find hydroponics an easy solution for growing plants as winter forces us to close our gardens. Urban gardeners with limited space or unsafe soil for vegetables will also find that hydroponic gardening offers new opportunities to grow vegetables year-round, even on concrete.

Hydroponic systems must deliver the essential components of plant life normally found in the garden. These are light, air, nutrients, and water. All methods of hydroponics have the advantage of efficiently delivering water and nutrients to plants. Large, complex hydroponic systems utilize energy to deliver these components in a finely tuned way. There are many designs including, Nutrient Film Technique, Ebb and Flow, Deep Water Culture, Drip System, and Aeroponics to name a few. All of these are considered Active Hydroponics because they require some sort of pump, aerator, or timer to make the system work. Sometimes these are all set up to a finely calibrated computer sensor that monitors the whole system. These active hydroponic systems can be advantageous for large scale crop production and plants that take a long time to harvest but will likely lead to frustration for the beginner hydroponics gardener.

In Passive Hydroponics a plant's ability to suck up water is utilized to drive the system. This is also called the Kratky method of hydroponics and effective, even attractive systems can be built from plastic buckets, mason jars, or wine bottles. As the plant grows, utilizing nutrients and water from the bucket, water level decreases pulling air down into the system to keep roots aerated. The plant effectively becomes the pump for the system. With an appropriately set up passive system the nutrient solution will not need to be changed during the maturation of the plant before harvest.  However, to take advantage of this simplicity, it is important to choose the correct types of plants for passive hydroponics and take care during initial system set-up.

Plants such as lettuce, kale, and non-woody herbs whose leaves are harvested frequently or all at once after several weeks in the system grow well in passive hydroponics. Plants that are harvested after fruition, such as cucumbers or tomatoes, are not good candidates for passive hydroponics because nutrient levels must be closely monitored and changed throughout the life of the plant for a good harvest. Similarly, long-lived plants or perennials can outgrow the system or may require nutrient solution changes so frequently that the simplicity of the system is negated.

Before setting up your system, start off with sterile seedlings or cuttings. Do not place any plant in your system that has been in contact with soil or soilless media. Doing so can inoculate the system with harmful microbes. Seeds or cuttings started in rockwool cubes are often recommended; however, you may find success with other methods. Experiment after you get started but do not reuse the propagation material. Fresh, unused propagation material is recommended to limit potential contamination.

For setting up a simple and effective lettuce growing system you can start off with a black, food-safe plastic 5-gallon bucket and lid. Many hydroponics suppliers have a wide selection of choices. Black limits light into the nutrient solution which could cause algal growth and food-safe plastic offers peace of mind. You can drill lids to accept mesh cups or choose from a wide variety of molded lids for different set-ups. You may need expanded clay pebbles to add stability to your plant depending on the design you go with. Before starting, rinse all the materials you will be using and spritz with a 10% bleach solution then allow to dry.

Tap water can contain high enough levels of chlorine to impact some plants. To set up your system it may be best to use distilled water. At a minimum, allow tap water to sit for 24 hours before mixing in nutrients. Following the directions on the label, mix in water-soluble nutrients at the rate suggested. Using nutrients designed for hydroponics will be helpful. After adding nutrients your solution pH will be still close to a neutral 7. The solution must be adjusted to 5.5 to 6.0 for optimum nutrient uptake. You can use white vinegar to lower pH. Typically, 2 teaspoons of white vinegar per gallon of water will adjust the pH appropriately. Cheap and simple pH testing strips are a good investment in checking pH. If the pH of your nutrient solution is not 5.5 to 6.0 your plants will not be able to absorb all the nutrients.

Set up your system when seedlings have roots long enough to touch the nutrient solution in your system. In a 5-gallon bucket, the nutrient solution should be 2 to 3 inches below the top of the bucket. This allows an initial air pocket which is critical for root health. Set your system in an area with good light and airflow. This could be a back patio, front stoop, or well-lit room. Supplemental light from basic fluorescent bulbs or LEDs designed for plants are helpful and may be necessary for indoor setups. Harvest your lettuce as you would normally. After mastering this system get creative and experiment with using dark-colored beer or wine bottles to grow plants in windows for a unique kitchen aesthetic. Or, take the leap into active hydroponic systems for some impressive hydroponic gardening.

For additional information visit:  Set It and Forget It Hydroponics