Although organic options are available for hydroponic growing, it is usually preferred to keep the hydroponic water as near sterile as possible. The reservoir and hydroponic system in general provides your plants with the food and water needed for it to grow and thrive. Unfortunately this also means a perfect environment for pathogenic and undesirable organisms to grow and thrive as well.


Bacteria and fungi thrive in the nutrient and moisture rich environments of hydroponic systems. Bacteria are single celled organisms that grow and multiply at incredibly fast speeds, and can become a problem in a matter of days if allowed to thrive. Being only single celled organisms however, they lack the ability to resist and defend against strong changes in their environments in the same way that plants have.

For example, plants have the ability to produce defensive cells on the root surface that takes the brunt of any abrasive or corrosive materials in the soil. They are basically designed to die and function as a shield for the living cells below. Bacteria do not have this ability, since they are only a single celled organism, and do not have the ability to spare cells as shields in this way. This is only one example of how plants can resist damage from their environment better than bacteria can, but there are many other examples of this.


How to keep the growing environment clean and disease free

Complete sterility is not possible in hydroponics and would result in the death of your plants. There are precautions however that can be used to make your hydroponic growing medium as close to sterile as possible without putting your plants in danger:


1. Change the reservoir water weekly

The easiest way to maintain the sterility of your hydroponic system is to change the reservoir water often. Once a week is sufficient for ensuring that you are not wasting your nutrients by dumping them away long before your plant even has a chance to use them, but before bacteria has a chance of taking over. When changing your reservoir it is also a good idea to give the inside of the tank a wipe to remove any adhering bacterial film, and clean the filters of any pumps or the surfaces of your air stones. These are all places where bacteria tend to hide, where they can then come out after new water is added to begin multiplying once more.


2. Use only clean, filtered water

Many consider this the most effective way of keeping your reservoir clean, but is not the easiest or the cheapest. You will need to purchase a filtration system, or buy filtered water in order to achieve this. Although this brings some added costs to the system, it will go a long way in preventing contamination and disease in your hydroponic system.

Reverse osmosis is by far the best option for this, as it removes up to 99.999% of the dissolved molecules of your tap water. It is virtually sterile from the beginning. Combine this with weekly reservoir changes and you will likely never have a problem with bacterial overgrowth in your hydroponic system. By the time bacteria get a chance to multiply you will have flushed the system and filled it once again with new filtered water.


3. Add enzymes or hydrogen peroxide to your water

Enzymes and hydrogen peroxide are great options for managing systems that already have some degree of bacterial or fungal growth, but are also useful as a preventative. Enzymes are a protein that have the specific task of breaking down dead materials. They can be added to your reservoir to attack and destroy any dead pieces of roots, dead bacterial bodies, or algae which would otherwise be used as food for fungi or bacteria. Removing this food source will help to deter and slow the growth of pathogenic organisms from taking over your hydroponic system.

The other option, hydrogen peroxide is useful in another way. Hydrogen peroxide is an oxidising agent, which means when it come into contact with a cell membrane it steals electrons from the surface, which causes it to fall apart. With bacteria and fungi, which are generally single celled organisms, this can easily kill the organism, even in low doses. More complex organisms like plants, which use many cells that all work together to live and work, have a much better ability of resisting oxidation. Plants actually produce chemicals specifically intended towards eliminating oxidising agents and prevent them from damaging the roots when given in low doses. This means that a gentle application of hydrogen peroxide to the reservoir can result in the mass death of bacteria and fungi without affecting the health of your plants.

It should be noted that hydrogen peroxide and enzymes should not be used together as the peroxide will also generally kill the enzymes as well.


4. Use chemical fertilizers

Chemical fertilizers are very misunderstood. Most people hear “chemical” and immediately associate it with negativity. All fertilizers are chemicals, no matter whether they are organic or not, the plant only sees the chemical structure of the fertilizers and does not care what the source of that chemical is. Bat guano for example is an organic fertilizer, yet is broken down into its individual components such as nitrogen, phosphorous, and potassium once reaching the plants roots. Chemical fertilizers simply offer the same nutrients only in more specific formulas that are already contained in the broken down versions. The plant then converts these nutrients into whatever structure or function it needs irrelevant of the original source.

The difference then, is that many of the organic fertilizers are not sterile to begin with. They come from natural sources, and therefore contain the natural bacteria, and fungi that comes along with them. Chemical fertilizer salts on the other hand are perfectly sterile as they are not extracted or collected from any direct living organism. Once being mixed into your water they do not add or inoculate any such organism into the water along with them. This goes a long way in maintaining the sterility and cleanliness of your hydroponic solution.


Keeping the reservoir clean is simple and straightforward

Keeping the reservoir water of hydroponics is crucial to your success as a hydroponic grower. This task may seem daunting at first, but with regular attention and a few precautions it will prove to be an easy and straightforward process that will go a long way in maintaining the health and yield of your plants.