Hydroponics may seem like a modern technical marvel, but the truth is it has been around for most of modern history. The ancient Egyptians used it, as evidenced in their hieroglyphic writings. The Romans used it to grow food out of season. Today, it used to grow plants that are bigger, stronger, and more productive than anything that could be grown in the ground.
There are many advantages to using hydroponics over traditional growing methods. Hydroponics allows a grower to precisely control the water and nutrients a plant receives, as well as control the pH level, things that are very difficult to do with plants growing in soil. With hydroponics there is no pest or weed issues, no need to fertilize, use pesticides, use herbicides, or rotate crops. It can be done in a confined space, such as an apartment or balcony, and as implied above, can produce a much higher yield than with traditional methods.
Here are the general hydroponic systems available today, how they work and their advantages and disadvantages.
In a solution culture, there is no medium used for soil. The plant’s roots are placed directly into a nutrient solution, or even hang in open air.
Static solution cultures are some of the simplest forms of hydroponics. In them, plant roots are placed directly into a nutrient solution, and kept there.
1) Full Submersion
Full submersion is where a plant sits in a container filled with nutrient solution. The container can be as basic as a glass jar.
2) Lettuce Raft
In this system, holes are cut into a raft. In these holes low-lying crops, such as lettuce, are placed. The raft floats on a pool of nutrient solution, oxygenated with bubbles, allowing the plant roots continuous access.
3) Wick System
In a wick system, the growing tray stands over the nutrient solution, separated by space with only one or several wicks connecting them. The wicks serve as a choke point, allowing for a controlled flow of nutrients from pool to plant, with no maintenance needed.
Continuous Flow Solution
In these systems, nutrient solution continuously flows past the plants roots. This allows for easy automation, where nutrient levels, pH balance and temperature of the solution can be controlled within a storage tank.
In these types of systems, the disadvantage is relying on all parts of the system to work properly, particularly the pump. A functioning pump is of the utmost importance. They are relied on to deliver nutrients and water in a timed manner, and if they stop working the plant roots can dry out quickly.
1) Ebb and Flow/Flood and Drain Systems
These types are the simplest and most common. The plants sit in a growing tray, and every few hours the tray is flooded with nutrient solution. It is then allowed to drain back into the storage tank.
2) Drip Systems
In a drip system, solution is continuously dripped onto the roots of the plant.
3) NFT (Nutrient Film Technique)
In these systems, nutrients are pumped to the top of a long, slightly inclined growing area. The solution flows down the incline, feeding plant roots.
In NFT systems there is sometimes an issue with the plants at the front having first dibs on nutrients, and growing larger. Having multiple injection points can solve this problem.
In aeroponics, plant roots are suspended in air, and at regular intervals are fed through a mist of nutrient solution sprayed at them. The goal is to expose the roots to the highest amount of air as possible, while supplying all the nutrients they need in ideal proportions.
In Aerponic systems, plant roots absorb nutrients at a faster rate than any other method, leading to a greatest volume of growth of all the hydroponic techniques.
The disadvantages are high cost (as it is equipment intensive) and the need for greater maintenance (as the life of the plant relies on the pump working properly). For these reasons it is not popular among beginners.
A variation of this is to have the nutrient solution lying in a pool a few inches below the roots. Oxygen is pumped into the pool, forming bubbles that rise to the top and burst. This burst creates a send off of mist that feeds the plant roots.
(THIS SECTION FIRST APPEARED IN THE ARTICLE WHAT IS HYDROPONICS?)
In a medium culture, there is a solid medium for the roots to be contained in. The material used is inert (doesn’t supply nutrients to the soil) and is simply used as a solid structure for the roots to live in. Some common materials used in medium culture hydroponics:
Rockwool: Often used in drip irrigation systems. It is excellent at retaining water, and good at holding air.
Oasis Cubes: These are small cubes, good for starting seeds or cuttings. They are pH neutral, retain water, and can easily be placed in the soil or into a hydroponic system.
A 50/50 Perlite and Vermiculite Mix: These two mined materials complement each other nicely. Perlite is great for aeration and soil drainage. Vermiculite is great at holding onto water. A balanced mix of the two results in a great medium for plant growth.
Coconut Fibre: One of the top performing growth mediums. Contains hormones that stimulate roots and helps protect against disease and fungus infestation. A 50/50 mix of coconut fibre and expanded clay pellets in an extremely effective growth medium.
Good luck and stay prepared!