Hydroponics - The Other Gardening, Part 1: Hydro Basics

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“What in the marthaforkin’ heck is hydroponics?… isn’t that a type of tomato?“

First off, no, it’s not a tomato…Very simply, if a plant (or crop) is grown without using soil and fed with a complete nutrient fertilizer, that’s hydroponics! It can be as basic as growing a plant in a pot of sand or cube of rockwool, or as complex as re-circulating deep water culture and aeroponic systems.

“Don’t plants NEED soil to grow?”

No, soil is NOT essential to plant growth. In fact, plants need 17 elements to sustain life and growth, and soil is not one of them; here’s why… Researchers in the 18th century found that plants absorb minerals from nutrients as inorganic ions in water. Soil contains composting materials that are constantly being consumed by worms, bacteria and other micro-organisms. This process creates ions (inorganic elements) that are dissolved in water. In hydroponics, nutrient minerals are applied directly to the water supply, completely eliminating the need for soil and soil organisms.

“Doesn’t organic soil-grown produce smell and taste better?”

The short answer to that is no, not necessarily. The general question of ‘organic vs. hydro’ is a Pandora’s box in the gardening world, with many gardeners firmly (and sometimes angrily) choosing sides. I can make valid points for both, but that argument is best saved for a different day, different article…

“Why should I go hydro? Mother Nature seems to be doing very well with soil…”

There are many good reasons to grow in a hydroponic system. One of the main reasons to go hydro is simply not having to deal with soil. That stuff is heavy, and not to mention dirty. Because it comes from the outdoors, soil can also introduce unwanted pests, like thrips and spider mites, to your grow room. Aside from that, the benefits of hydroponics are numerous. Nutrients are given to plants directly and at very precise levels. When done right, this results in growth rates and yields that are much higher than what soil/organic methods can achieve. Because of this, hydroponics have become a staple in the horticulture and agronomy industries.

“Sounds easy. I think I’ll go with hydro for sure!”

Not so fast my friend. Plants grown in a hydroponic system can have definite advantages over their soil grown counter-parts, but I never said it was easy. Hydro systems require that the PH and TDS of the nutrient solution be checked frequently, if not daily. Doing this ensures your plants are receiving the proper amount of minerals in the correct PH range. Also, because hydroponic nutrient solutions are made so readily available to plants, over-feeding is common. It can take multiple grows with the same variety of plant to successfully “dial-in” your feeding levels and schedule for maximum results.

This isn’t to say that growing in soil is easy either. Truly mastering either method requires knowledge and experience, and sometimes a lot of patience.

“OK, I think I’ll still give hydro a shot. So how much $ am I looking at spending?”

That depends. As I mentioned above, hydroponic gardening can be as simple as growing a plant in a pot full of sand. Add a crude siphon fed drip line to that, and you have a hydro system for under $5. If you decide on a more advanced system, your costs will range from around $50 for a top feed bucket to over $1000 for large multi-site systems. Other items to consider when purchasing a hydro system include water testing meters and kits, water chillers/heaters, and even water purifiers.

“What are the different ‘systems’ you keep referring to? And which one should I use?”

The question of which system to use really comes down to a matter of personal preference and which one best fits your needs. Each system has its advantages, and each has its limitations. When trying to choose one, the first thing you should consider is the size of your grow space. A 60 site Aeroflo won’t do you much good in a 2′x4′ space, while something like a Microgarden or Turbogarden would fit that space nicely. There are other things to consider besides size; so let’s take a closer look at some hydroponic systems and methods, and examine what makes them unique.

Static Culture
In a static culture system, plants are grown in containers of nutrient solution. The container can be anything from tubs, jars, or plastic buckets. The solution is usually aerated but does not have to be. If left with no aeration, the solution level is kept low enough that the roots are above the solution so they get plenty of dissolved oxygen. A hole is cut out of the lid of the container to accommodate one or more plants. An increase in container size may be necessary as the plants grow. If a high solution level is maintained, aeration must be used to provide oxygen to the plants roots. This is typically done with an aquarium or commercial air pump attached to air hoses and an air stone/diffuser. Clear containers must be completely blacked out as so no light gets to the solution. Light leaks to the water solution will cause algae to grow. The nutrient solution is changed on a controlled schedule. A float valve can be added to maintain water level with adding premixed nutrient solution. This way the solution will never drop below the required level.

Continuous Flow Culture, or NFT (Nutrient Film Technique)
In this technique the flow of nutrient solution is always (or “continuously”) being passing through the roots. This system is a little easier to automate than the static solution culture because taking readings and adjusting your nutrient concentrates happens in a larger storage tank (reservoir). The most widely used variation to this method is the NFT(nutrient film technique), whereby a very shallow stream of water containing all the dissolved nutrients is re-circulated past the bare roots of plants in a watertight thick root mat, which develops in the bottom of the channel. an abundant supply of oxygen is provided to the roots of the plants as well. NFT’s are designed to have the correct slope and channel length.

Gravity Fed Systems
This system brings nutrient solutions to the plants without the use of electricity, and instead using gravity. The solution is placed over a series of hydroponic pots. Each pot has a check valve to ensure an adequate amount of nutrients to the pot. Capillary action draws it up into the roots of the plant. This system is like a large constant feeding dog dish.

Aeroponics is a design that continuously keeps a very saturated environment by spraying or misting the root systems. These systems are set on timers to periodically spray the roots with the mineral nutrient solution. This also allows for excellent aeration of the nutrients. The advantage of aeroponics is that suspended plants receive 100% of the available oxygen and carbon dioxide to the roots zone, stems, and leaves,[11] thus accelerating biomass growth and reducing rooting times.

Passive Sub-Irrigation, or Wick System
This is also known as passive hydroponics or semi hydroponics, Where in this method plants are grown is a porous medium that transports the nutrients to the roots using capillary action. The pots sit in a shallow pool of solution and the plants draw the nutes up. There are alot of different mediums used in this technique. An advantage of passive hydroponics is the reduction of root rot due to less humidity.

Ebb and Flow or Flood and Drain Sub-Irrigaton.
In its most standard form, this method consists of a tray above a reservoir of nutrient solution. Either the tray is itself, or individual containers are filled with a medium. At regular intervals, a timer causes a submerged pump to fill the upper tray with nutrient solution. Once the upper tray fills past the high water drain, the solution begins re-circulating until the pump is turned off. When the pump no longer on, the water in the upper tray drains back into the reservoir. This flood and drain action keeps the medium regularly flushed with nutrients and air.

Deep Water Culture (DWC) and Re-circulating (RDWC)
In this method a plant is suspended above an aerated and oxygenated nutrient solution. This traditionally favors the use of 5 gal buckets or large containers. Plumbing these buckets together and connection them to a reservoir and pump will create a re-circulating deep water culture or RDWC. The keys to these systems is good solution movement and lots of aeration. The bigger the air pumps you supply, the better as you can never have enough good dissolved oxygen. An additional way to run this system is called bubbleponics. This method adds a top feed system to the deep water culture bucket.

That my friends is hydroponics, the basics. We’ll be covering some of the systems above in more detail, and also debate the ‘organic vs. hydro’ issue in future articles. But, that’s it for now. Remember to have fun, love your garden, and grow BIG flowers!




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Hydroponics - The Other Gardening, Part 1: Hydro Basics

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Hydroponics - The Other Gardening, Part 1: Hydro Basics

This article was published on 2011/05/09