Hydroponics 101

About Hydroponics

• Hydroponics (HY-dro-PON-ix) literally means "working water".

• Plants grown hydroponically can mature 25% faster and produce 30% more than the same variety grown in soil. This is because plants are grown in a readily available nutrient-rich solution and they don't have to spend valuable energy developing roots to seek out food.

• In hydroponics, the grower is responsible for providing all the necessary nutrients.

• Because hydroponics systems typically recycle the nutrient solution, plants in these systems actually use less water than their soil-based equivalent.

• Hydroponics can be set up indoors and out.

• Great for those with limited gardening space because several plants can be grown together in a small area. Plus you rarely contend with soil-borne disease or weeds!

Types of Systems

Passive

If you've ever taken a cutting from a houseplant and placed it in a container of water to establish roots, you've used a passive hydroponics method! With no moving parts, passive systems are great for beginners because they are inexpensive, portable, and simple to set up and maintain.

Active

Active systems, on the other hand, employ pumps and other devices to deliver nutrient solutions to plant roots. Here are some of the preferred types of active techniques:

Deep Water Culture (or Continuous Aeration Technique): With this self-contained method, plants are suspended above the water level and a submersible pump is used to constantly bathe roots in nutrient solution. As plants mature, the roots will grow into the continuously circulating reservoir. See the Garden, Planter and Jungle of Ease.

Flood and Drain (or Ebb and Flow): For this approach, plant roots are intermittently flooded with nutrient solution. The frequency of the flood depends on the type of growing medium and the size and type of plant, but typically 15 minutes every 2-4 hours during the day. Roots are nourished and aerated as the cycle repeats. Many boxed kits, plus mix and match components are available.

Drip: This is a substrate system where a pump delivers solution from a main reservoir to drip emitters positioned at the base of each plant via individual supply lines. Depending on the growing medium, some will drip continuously, others are set on a timer to drip 15 minutes every 2-4 hours during the day. Drip systems that use stonewool cubes and slabs give you the most "margin of error" as they retain water incredibly well. See the CocoGrower, EuroGrower, EcoGrower and Waterfarm.

Aeroponics: In aeroponics, plants are suspended without the use of a growing medium and their roots are continuously sprayed with a fine nutrient- and oxygen-rich mist. With this virtually unlimited access to oxygen, roots have maximum potential to absorb nutrients and plants can grow at a phenomenal rate. These systems have a small margin of error and are recommended for more experienced gardeners. Delicate sprayer nozzles must be kept free of debris as they can clog easily, and equipment or power failure can cause total crop loss very quickly. Popular for cuttings and fast harvesting plants. See the AeroFlo, EZ-Clone, Nutramist and RainForest.

Nutrient Film Technique (NFT): A bare-root system in which nutrient solution is constantly pumped over plant roots at a depth of 1/4" to 1/2" to form a thin film of nutrient, giving roots access to nutrient and air simultaneously. The solution cycles between the main reservoir and the grow channel (or gulley) which is tipped at a slight angle to create the desired film effect and prevent roots from "damming" the channels.

Reservoir and Nutrient Solution Maintenance

What is pH, EC and TDS and why should I care?

For proper growth, plants need nitrogen, phosphorus, potassium (primary macronutrients), sulfur, calcium, magnesium (secondary macronutrients), iron, manganese, zinc, copper, chlorine, boron, and molybdenum (micronutrients). If the pH of your hydroponics nutrient solution is too high or too low, certain elements will become unavailable to your plants. Ranging from 0 (acid) to 14 (base), the pH scale is used to determine the acidity or alkalinity of a substance. As a general guide, most plants are happy between 5.5 and 6.8 pH. If left unchecked (and untreated), deficiencies can occur and lead to a variety of problems. Variables such as evaporation, temperature, and amount of light can affect pH levels. As such, frequent monitoring of nutrient solution pH levels is critical.

Aside from staying on top of pH levels, you should also test the strength of your nutrient solution because, as the water in the solution evaporates, the nutrients become more concentrated. Also, as the plants take in what they need, the nutrient concentration can, in turn, weaken. Since hydroponics nutrients are mainly made up of salts, and salts in solution conduct electricity, you can measure the concentration of your nutrient solution by measuring the electrical conductivity (EC). Hydroponics gardeners can also determine the strength of the nutrient solution by examining the total dissolved solids (TDS) in a simple ratio known as parts per million (ppm).

How to check pH, EC and TDS.

Meters are the easiest way to determine the pH and nutrient strength of your hydroponics reservoir. Available as handheld portables or wall-mountable testers that take constant readings, there are several varieties to choose from. Some are specific to each test while others can check pH, EC and TDS in addition to temperature. Regardless of the type you choose, keep in mind that meters require regular calibration and cleaning to maintain accuracy.

If you find that your solution is too acidic or too alkaline, you can easily make incremental changes in pH with pH up or down additives as needed. Similarly, if your solution is extremely concentrated or weak, you can resolve the respective issue by diluting with water or adding more nutrients.

Other Useful Tips

• It's a good idea to change the nutrient solution in your reservoir about once every two weeks.

• If plants show discolorations or distortions, first check and correct the pH. If pH is not the problem, perform a nutrient flush with a product like Clearex, Final Flush or Flora Kleen, and consider using a micronutrient supplement to correct the problem.

• Plants don't like "hot or cold feet" so make sure your water is between 65 and 75 degrees Fahrenheit. Reservoir heaters can help raise and maintain temperatures.

• Pair an air pump with flexible air tubing or an air stone to increase circulation and add oxygen to your reservoir.

• When you have just finished a growing cycle or you're about to start a new one, you'll want to drain your reservoir, remove any plant debris you can find, and run a light, non-chlorine bleach solution—about an eighth of a cup for every gallon of water—through the system for about half a day. Then, drain your reservoir again and run fresh water through the system to remove any traces of bleach.

• Be sure to add nutrients and supplements according to their label instructions and add multiple-component nutrients separately.

Growing Media Options for Hydroponics:

• Stonewool provides a superior air-to-water ratio, a clean start for cultivation and strong structural support for plants. Compatible with most ebb and flow and drip systems, stonewool is available in several shapes and sizes.

• Expanded clay pellets are porous to leave plenty of room for air transport and root development while retaining moisture. This reusable clay aggregate is chemically inert with a neutral pH. Hydroton brand is a tried and true favorite.

• Silica stone is a lightweight and super-absorbent mineral that is completely non-toxic to plants and the environment. Over time, silica stone will deliver trace amounts of silicon to plants - which has been proven to strengthen them on a cellular level and contribute to faster growth, stronger roots, and improved resistance to pests and environmental stress.

• Coconut fiber - or coir - is a by-product of the coconut industry and a sustainable alternative to peat moss. Coconut coir is available as preformed pots, grow cubes and mats in addition to compressed and loose-fiber formulations.

• Perlite and vermiculite can be used by themselves or in combination with other additives to create a soilless mix for hydroponics. Vermiculite retains moisture well and perlite allows for adequate oxygenation. These are great for lightweight plants such as lettuce because they do not crush fine stems and delicate root systems.

A Quick and Easy Do-it-Yourself Hydroponics System

What You Need:

• Standard 5-gallon bucket

• 10" bucket lid

• Submersible water pump, 250-350 gph

• 2' section of 1/2" black tubing

• Heavy-duty rubber band

• Growing medium of your choice - we recommend Hydroton or Sunleaves Silica Stone

• Hydroponics nutrient of your choice

• Sharp, sterile cutting utensil (utility knife or similar)

• Plant you wish to grow

Start with a clean, food-safe five-gallon bucket to serve as your main hydroponics reservoir. Next, take your utility knife and carefully poke multiple holes along the length of your 1/2" tubing to effectively convert it into a spray line. Attach the 1/2" tubing to the submersible pump and position the pump in bottom of the bucket. Fold over the opposite end of the tubing and secure it with the rubber band. The tubing should now be connected to the pump on one end and closed off on the other. Now you want to coil the tubing within the bucket so that it gradually rises from bottom to top and rests along the edge of the bucket. Fill the bucket three-quarters of the way with water and nutrient (mixed according to instructions on label) and place the 10" lid in the bucket. Fill the lid one-half to three-quarters of the way with growing medium, add your plant and top off the lid with the remainder of medium.

Plug in your system and enjoy!