Hydroponic Basics

What is Hydroponics?

A person is holding a container in the grass.

Hydroponics is the method of growing plants in a solution of water and nutrients with or without inert growing media such as sand, coco, perlite, and hydroton. These media are used for supporting the plant and to keep the nutrient solution close to the roots. Hydroponic nutrient solutions are typically aerated because the roots need oxygen for respiration and growth.

What is Aeroponics?

A diagram of the aeroponic system with water and plants.

A plant-cultivation technique in which the roots hang suspended in the air while nutrient solution is delivered to them in the form of a fine mist. Aeroponic systems utilize misters and sprayers that periodically spray the roots with aerated nutrient solution. This type of system is a little more difficult to operate but the rapid rates at which plants grow results in amazing yields.

Advantages

  • The biggest advantage with hydroponics is the increased growth rates so you get maximum yields in the shortest amount of time. With a properly set up system, your plants will mature faster and provide over 30% increased yields. Properly set up systems include maintaining control of light levels, pH, nutrient solution strength, levels of dissolved oxygen in water, ventilation, and pest control.
  • Plants grown hydroponically always have an unlimited supply of water and nutrients which allows the plants to focus most of their energy growing shoots, foliage, fruits, and flowers.
  • Plants can be grown hydroponically both indoors and outdoors
  • Any plant can be grown hydroponically!

If you are not growing hydroponically, don't worry, Blue Planet Nutrients works excellent in soil as well!

Water Quality
Water is the foundation of all hydroponic systems. It is very important to know the quality of the water being used because most water already contains various minerals which can effect the pH stability of your nutrient solution as well as the availability of the nutrients for absorption by plants.

How Important is Water Quality in Growing?

A white shower head sitting on top of a floor.

Water containing excessive calcium and magnesium (ie. "Hard-Water") can cause serious problems. If the dissolved salts in your water supply measure 200 ppm or more, we strongly recommend that you obtain a water analysis to determine calcium content. Excessive calcium is the main factor in determining if your water is hard. If an analysis of your water supply reveals that the calcium content of your water supply is greater than 70 ppm (mg/liter) you should consider purchasing a reverse osmosis water filtration system to filter your water.

Is Chlorinated Water a Problem?

The most common issue regarding tap water and hydroponics is chlorine. Many growers don't realize that chlorine is a micro-nutrient required by plants in extremely minimal quantities. Chlorine is highly volatile and will evaporate from tap water within a day or sooner if the water is aerated. Because plants are able to absorb it, they wind up taking in far too much from unfiltered tap water resulting in diminished growth due to poor root health. The micro-flora and micro-fauna living in the root zone are very important for healthy vigorous plants and high yields. Don't let chlorine kill the good guys!

Chloramines are chemical compounds of ammonia and chlorine that are also used as municipal water supply sanitizers. Chloramines do not evaporate from water the way chlorine does and many water filters which remove chlorine cannot remove chloramine. The effects of chloramine on your garden are even more detrimental than chlorine. If you are concerned your tap water may contain chloramines, have it tested. To avoid problems caused by these chemicals, consider an investment in a water filter or reverse osmosis machine and make sure it takes out both chlorine and chloramine. The improvement in plant health can be considerable which translates to a substantial increase in harvest quality and quantity.

Oxygen and Roots?

A chart showing the temperature of an oxygen tank.

Plant root systems need oxygen for aerobic respiration, an essential plant process which releases energy for root growth and the uptake of nutrients. In a deep water culture hydroponic system, it is absolutely crucial to have adequate oxygen levels because roots are submerged. For optimal growth it is recommended to have 1 liter per minute of air pumped into each gallon of nutrient solution. Therefore a 100 gallon reservoir would require a 100 LPM air pump for maximum oxygenation. In every other hydroponic application it is only required to oxygenate the solution enough to prevent it from becoming anaerobic, which means much less air is required. Generally if you have good movement in the solution and the majority of the surface of the solution is broken with bubbles, your plants will do fine. This can be achieved with a simple fish tank pump and air stones.

What About Water Temperature?

As the temperature of your nutrient solution increases, the less your nutrient solution holds dissolved oxygen. The oxygen content of a fully aerated solution at 10°C (50° F) is about 13 ppm, but once the solution warms up to 20° C (68° F) the oxygen content drops to 9 – 10 ppm. By the time the solution has reached 30° C (86° F), then oxygen content levels are only at 7 ppm. We recommended not exceeding 76° F in your nutrient solution (ideal temp is 24° C or 70° F) in order to keep oxygen dissolved and available for plant roots.

6 Types of Hydroponic Systems

Deep Water Culture

This is the simplest hydroponic system there is. It is the easiest to use and produces wonderful results. In a DWC system, you use a reservoir to hold a nutrient solution. The roots of your plants are suspended in that solution so they get a constant supply of water, oxygen, and nutrients. Air stones and an air pump are used to oxygenate the nutrient solution allowing the roots to respire and grow.

What You Need to Build a Water Culture System:

  • Container to hold the nutrient solution (reservoir)
  • Aquarium air pump
  • Air line/hose
  • Air stones (or soaker hose) to create the small bubbles
  • Baskets, pots, or cups to hold the plants
  • Some type of growing media

How a hydroponic Water Culture system operates is easy. The plant is actually suspended in baskets right above the nutrient solution in the reservoir. Usually by cutting through the lid covering the reservoir. The roots hang down from baskets the plants are in, and hang down directly into the nutrient solution where they are submerged. The roots remain submerged all the time 24/7. The roots don't suffocate because they get the air and oxygen they need from air bubbles rising through the nutrient solution, as well as from dissolved oxygen in the water itself.

The more air bubbles the better for water culture systems. The bubbles rising should make the water look like water boiling at a heavy rolling boil. The bubbles should be rising up through, and making direct contact with the roots as they rise to the top of the water to be most effective for the plants.

Flood and Drain (Ebb and Flow)

Ebb and Flow (Flood and Drain) systems are very popular with home hydroponic growers for many reasons. Besides how easy they are for anyone to build, you can use almost any materials you have laying around to build them with, so you don't need to spend much money to grow plants hydroponically. Also they can be built to fit in any available space you might have (both indoors or outdoors), and there is no limit to the different and imaginative ways to design them for that space. Along with being inexpensive and easy to build, plants grow very well in flood and drain systems. The flood and drain system works basically like it sounds, by simply flooding the plants root system with nutrient solution. Only periodically rather than continuously.

How a hydroponic flood and drain system operates quite simple. The main part of the flood and drain system holds the containers the plants are growing in. It can be just one plant, or many plants/containers in series. A timer turns on the pump, and water (nutrient solution) is pumped through tubing from the reservoir up into the main part of the system using a submersible fountain/pond pump. The nutrient solution continues to fill (flood) the system until it reaches the height of the preset overflow tube so that it soaks the plants roots. The overflow tube should be set to about 2 inches below the top of the growing media.

When the water filling/flooding the system reaches the overflow tube height, it drains back down to the reservoir where it recirculates back through the system again. The overflow tube sets the water level height in the flood and drain system, as well as makes sure the water (nutrient solution) doesn't spill out the top of the system while the pump is on. When the pump shuts off, the water siphons back down into the reservoir through the pump (draining the system).

What You Need to Build a Flood and Drain (Ebb and Flow) System:

  • A container for the plant's roots to grow in.
  • A container (reservoir) to hold the nutrient solution.
  • A submersible fountain/pond pump.
  • A light timer to turn the pump on and off.
  • Some tubing to run from the pump in the reservoir to the system to be flooded.
  • An overflow tube set to the height you want the water level.
    Growing medium of some kind.

Drip Systems

Drip systems are one of the most widely used types of hydroponic systems around the world, both for home growers as well as commercial growers alike. That's mainly because it's an easy concept and needs few parts, but yet it's a very versatile and effective type of hydroponic system. Even though it's an easy concept, it won't limit your imagination when building your own systems. The way a drip system works is just like it sounds, you simply drip nutrient solution on the plants roots to keep them moist.

Hydroponic drip systems can easily be designed in many ways, as well as from small to large systems. But their especially useful for larger plants that take a lot of root space. That's because you don't need large volumes of water to flood the system, and the drip lines are easy to run over longer spaces. As well as when using a larger amount of growing media for larger plants, more growing media retains more moisture than smaller amounts, and that's particularly beneficial to large plants because it's more forgiving to the plants. Forgiving meaning that the plants arent as sencitive to watering times, so they don't stress imeditaly if they don't get waterd on time for one reason or another.

What You'll Need to Build a Drip System is:

  • A container for the plant's roots to grow in.
  • A container (reservoir) to hold the nutrient solution.
  • A submersible fountain/pond pump.
  • A light timer to turn the pump on and off.
  • Some tubing to run from the pump in the reservoir to the plants (and/or the drip lines if you use different sizes).
  • Tubing (PVC or flexible tubing) to run the return lines for the extra nutrient solution from the plants back to the to the reservoir.
  • (optional) You can use drip emitters, or you can just poke small holes in the tubing with a hot paper clip for the nutrient solution to drip out of like we like to do.
  • Growing media for the plants roots to grow in and help support the plants weight.

Nutrient Film Technique

The N.F.T. system is quite popular with home hydroponic growers as well. Mainly because of it's fairly simple design. However N.F.T. systems are best suited for, and most commonly used for growing smaller quick growing plants like different types of lettuce. Along with growing lettuce, some commercial growers also grow different types of herbs and baby greens using N.F.T. systems.

While there are a lot of different ways design an N.F.T. system, they all have the same characteristic of a very shallow nutrient solution cascading downward through the tubing. Where the bare roots of the plants come in contact with the water, and can absorb the nutrients from it. The major downside to an N.F.T. systems is that the plants are very sensitive to interruptions in the flow of water from power outages (or whatever reason). The plants will begin to wilt very quickly any time the water stops flowing through the system.

What You Need to Build a N.F.T. System:

  • Container to hold the nutrient solution (a reservoir)
  • Submersible fountain/pond pump
  • Tubing to distribute water from the pump to the N.F.T. growing tubes
  • Growing tubes for the plants to grow in (also called a gully/channel)
  • starter cubes, or small baskets and growing media to start seedlings in
  • Return system (tubing, channels) to guide the used nutrient solution back to the reservoir

How a hydroponic N.F.T. system operates is fairly simple. Nutrient solution is pumped up from the reservoir, usually to a manifold that connects the larger tubing to a number of smaller ones. Each one of these smaller tubes runs nutrient solution to one side of each one of the growing channels/gully's with the plants in it. A thin layer (film) of the nutrient solution flows through each of the channel's with the plants in it to the other side, passing by each plant and wetting the roots on the bottom of the channel as it does. The nutrient solution flows from one side to the other because the channel is sloped slightly so the water flows down hill.

The plants in the growing tubes (channel/gully) are typically suspended above the water by placing seedlings started in starter cubes or small one inch baskets of growing media into small holes in the top of the tube. The roots of the seedlings hang down to the bottom of the tube/channel where they get nutrients from the shallow film of nutrient solution flowing by. The excess nutrient solution flowing out of the low end of each of the channels drains into another channel or tube, and guided back to the reservoir where it is recirculated through the system again.

Wick System

The wick system is the simplest of all six types of hydroponic systems. That's because traditionally it doesn't have any moving parts, thus it doesn't use any pumps or electricity. However some people still like using an optional air pump in the reservoir. Because it doesn't need electricity to work, it's also quite useful in places where electricity can't be used, or is unreliable.

The wick system is an easy type of system to build when first learning about hydroponics, and/or you just your want to get your feet wet first. This type of hydroponic system is also often used by teachers in classrooms as experiments for kids. Both to help explain how plants grow, as well as getting them interested in hydroponics.

What You Need to Build a Wick System:

  • A bucket or container for the plant.
  • A bucket or container for the reservoir.
  • A good wicking growing media like coco coir, Vermiculite, or perlite.
  • Some strips of material like felt or good wicking rope.

How a wick system operates is like it sounds, it basically just wicks up nutrient solution from the reservoir to the plants using the process of capillary action. Meaning it sucks up water to the plants through the wick like a sponge. Typically good wick systems will have at least two or more good size wicks to supply enough water (nutrient solution) to the plant. The bucket/container with the plant in it basically sits right above the container used for the reservoir. That way the water doesn't need to travel up very far to get to the growing media with plants.

Aeroponics

While the concept of the aeroponic system is quite simple, it's actually the most technical of all 6 types of hydroponic systems. However it's still fairly easy to build your own basic aeroponic system, and a lot of home growers like growing in them as well, and even get really good results using this type of hydroponic system.

Like with any other type of hydroponic system, you can use many different kinds of materials to build it, as well as many different types of design setups to fit in your space. Your really only limited by the space you have, and your imagination.

Some advantages to using an aeroponic systems are they typically use little to no growing media. The roots get maximum oxygen, and the plants grow more rapidly as a result. Aeroponic systems also generally use less water than any other type of hydroponic system (especially true aeroponic systems). Also harvesting is usually easier, especially for root crops.

However there are a few downsides to aeroponic systems as well. Besides being a bit more expensive to build. The mister/sprinkler heads can clog from build up of the dissolved mineral elements in the nutrient solution. So make sure to have extras on hand to swap out when they do clog while you clean them. Also because the plants roots are hanging in mid air by design in aeroponic systems, the plants roots are much more vulnerable to drying out if there is any interruption in the watering cycle. Therefor, even any temporary power outage (for any reason) could cause your plants to die much more quickly than any other type of hydroponic system. Also there's a reduced margin for error with the nutrient levels in aeroponic systems, especially the true high pressure systems.

What You'll Need to Build Your Own Basic Aeroponic System:

  • Container to hold the nutrient solution (a reservoir).
  • Submersible fountain/pond pump.
  • Tubing to distribute water from the reservoir pump to the mister heads in the growing chamber.
  • Enclosed growing chamber for the root zone.
  • Mister/sprinkler heads.
  • Water tight container for the growing chamber where the plants root systems will be.
  • Tubing to return the excess nutrient solution back to the reservoir.
  • Timer (preferably a cycle timer) to turn on and off the pump.

How the aeroponic system operates is a fairly easy concept. First the purpose of the roots hang in mid air is so they can get the maximum amount of oxygen that they can get. The high volume of oxygen the roots get allows the plans to grow faster than they would otherwise, and the main benefit to this type of hydroponic system.

Second, there is typically very little if any growing media is used, exposing all the plants roots. The plants are suspended either by small baskets, or closed cell foam plugs that compress around the plants stem. These baskets or foam plugs fit in small holes at the top of the growing chamber. The roots hang down inside the growing chamber where they get sprayed with nutrient solution from mister heads at regular short cycles. The regular watering cycles keep the roots moist and from drying out, as well as provides the nutrients the plants need to grow.

The growing chamber the roots are in should be light proof, and almost air tight. It does need to allow fresh air in so the roots can get plenty of oxygen, but you don't want water to spill out, or pests to get in. Also you want the root chamber to hold in humidity. Ultimately what you want is the roots to get plenty of moisture, fresh oxygen, and nutrients. A a well designed aeroponics system provides a good balance of all three of those elements to the roots at the same time.

Lastly, a major factor in aeroponic systems is the water droplet size. Roots sprayed with a fine mist will grow much faster, bushier, and with more surface area to absorb nutrients and oxygen with than roots sprayed with small streams of water like from small sprinkler heads. That translates into the plant canopy growing more rapidly as well. Aeroponic system types are categorized by the water droplet size. e Nutrients

Hydroponic Growing Media

Expanded Clay Pellets (Hydroton)