Protecting your Nutrient Solution

Protecting your Nutrient Solution By Erik Biksa For the best results, growers tailor their nutrient solution composition throughout the different stages of their favourite plants' development.

There are many formulas in the market place, some have simplified mixing instructions, while others allow the grower a higher degree of flexibility in meeting their plants nutritional requirements. Plants, like people, will have changing requirements throughout different stages up to maturity.

In a micro-perspective, there are countless interactions occurring in the reservoir. The concentration, availability, and types of elements, compounds, and organic substances are constantly undergoing complex changes. The longer a nutrient solution is active, the greater the potential for change. So how can we protect the integrity of our nutrient solution, to ensure that the plants will receive a balanced uptake of the elements and compounds they require, while reducing the potential toxicity from buildups or adverse reactions occurring in the reservoir?

The first step is to start by mixing your nutrient solution with the highest quality water available to you. Keep in mind that mature plants can transpire tremendous volumes of water on a daily basis, so your source will also have to be practical. Ideally, your water source should be less than 100ppm in Total Dissolved Solids (TDS) and relatively neutral in pH before any nutrient additions are made. If this doesn't sound like an accurate description of your water source, do not panic. There is much that can be done to improve the quality of your water, thereby improving the results you achieve from your crop. I have spoken with experienced growers who practice sound growing methods with the appropriate varieties and planting densities but are not able to achieve the type of results that they would expect. After further discussion, I often find that the TDS of their water has been 300ppm+ before any nutrients have been added to the water. It is fairly safe to say that they are dealing with "hard water". Ideally a water analysis should be obtained to determine which elements can become over abundant, locking out other nutrients. Hard water tends to contain elevated amounts of calcium, magnesium, and sulfer, among other elements. Generally, water boards determine the hardness of water by the amount bi-carbonate present. These elements are essential to plant growth, but if not in balance with other elements in the nutrient solution, they can be detrimental to plant production. Plants might show deficiencies of phosphorous, iron, or zinc although present in the nutrient solution. If an element is in excess, other elements may become "locked out", as certain elemental ratios are required for optimal uptake by the plant.

For example, if you discover that you will be using hardwater for your next crop, you might consider one of the following options: 1) Reduce the "hardness" of your water supply -- This can be done by distilling the water (including solar distillation) or by filtration of dissolved solids. Reverse osmosis will effectively reduce the level of dissolved solids in your water, but the process is slow, so make sure that you have an accurate estimate of your daily water requirements, as RO devices list their daily output potential.
2) Use a high quality nutrient solution intended for use with hardwater. If you have greater than 75 ppm of calcium present in your water supply it is recommended that you use a hardwater formulation. If less than 75ppm of Calcium is present in the hardwater, try using half hardwater formula and half regular formula. If in doubt, try the "half and half' and experiment from there. Most growers who have been using hardwater to mix their nutrient solution are pleasantly surprised at harvest after switching to hardwater nutrient formulations. Well water is typically considered hardwater.

To growers with diseased plants, my first response is usually "prevention is the best cure". I realize that this might be frustrating, but it is true, and can save your money and health by avoiding toxic fungicides, etc. because your crop has become infected through a lack of preventative management.

Contaminants in the water can very adversely affecting the performance of your crop. Although community water supplies are typically treated for safe human consumption, they are not treated with plant welfare in mind. Rhizoctonia and fusarium, to name a couple of pathogens, can be present in your water supply and are vectors for causing plant diseases such as root rot. Viruses may also be present. Reverse osmosis may help to remove some pathogens, but for the highest level of protection, the water should be ozonated prior to mixing up your nutrient solution.

Some growers have been pre-treating their water with 35% hydrogen peroxide (food grade) to purify the water. Hydrogen peroxide (H202) is essentially water with an extra oxygen molecule attached to form the compound. It is relatively unstable, so the extra oxygen molecule is looking to break free from the compound and attach itself to another particle. In doing so, organic particles present in the water are oxidized "killed". Since the extra oxygen molecule has become neutralized, the remaining by-product is simply water (H20). Unfortunately, the additions of hydrogen peroxide do not create ozone gas in the water to effectively purify the water, only some of the organic matter present becomes oxidated or sterilized. Even if only a few spores survive, they will quickly multiply and infect your plants given appropriate conditions. With the increasing pressures for commercial growers to use re-circulating nutrient solutions, there has been a respectable amount of research with regards to inline U.V. sterilizers, as both a pre-treatment of water and used directly with the re-circulating nutrient solution. Used inline with nutrient solutions, U.V. sterilizers can help to reduce spore populations in the nutrient solution. Spore may survive being irradiated with UV light if they are "hiding" behind organic particles in the nutrient solution (i.e. organic supplements or root debris) as they pass by the light. Many studies suggest that U.V. sterilizers used in-line with recirculating nutrient solutions can break down the chelates (pronounced "key-lates") associated with most trace elements, thus making them unavailable to plants.

For pre-treatment of water to be used for nutrient solutions, U.V. sterilizers cannot offer complete purification. It is speculated that low gas concentration of ozone is produced as a by-product of U.V. irradiation, but is not produced in sufficient quantities for a long enough contact time in the water, before it dissipates through the water surface as a gas. Think of an ozone exhaust cleaner: 25 feet of ducting is always recommended after the ozone device, so that the ozone can mix with the air, as the reaction is not simultaneous. In order for ozone to be effective in water purification, huge quantities of ozone gas must pass through the water before escaping as a gas. In a sense, the water must be saturated with ozone.

The answer can be found with corona discharge water purifiers. They work with the following principle(s): A high concentration of ozone is first created in the air, which must then be bubbled into the water where it dissolves. After dissolving into water it is free to "seek and destroy" impurities in the water that can harm your crop. Any leftover ozone will escape the water as a gas, and the by-product of ozone that has reacted to neutralize impurities will be dissolved oxygen, which is required in abundance to fuel plant growth. If the ozone concentration output from the device is less than 250ppm, very little ozone will dissolve into the water, and will escape as a gas, having little effect in improving your water quality. When looking for corona discharge units for water purification, look for ones where the housing is not constructed of materials that could conduct electricity (i.e. metal). Tremendous voltages are being generated by the internal transformer to produce the ozone, it wouldn't be fun to learn "hands on" that water and electricity do not mix.

So, now you have water that would make Evian jealous, and you have high quality nutrients that can be tailored to your crops' changing requirements. The next step in protecting your nutrient solution is to ensure that all the individual elements present will continue to get along with each other and the plant as the chemistry begins to change, as elements and water are absorbed and organic acids are secreted back into the solution by the plant. Some elements are typically more difficult for plants to absorb than others. This is one of the main reasons that many micro nutrients are chelated. Chelates are chains of elements that attach to a plant required element such as iron that make it more available to the plant. Typically, if not supplied in a chelated form, plants will show nutrient imbalances or deficiencies, although a form of the required element(s) is present in the nutrient solution--it's simply unavailable to plants. If you have ever had to give a pet some medication, it's often easier to wrap a pill in a piece of meat or cheese than to simply try and force the pill down their gullet.

However, unlike pets, the plants will not absorb the "meat" or "cheese" to get the "medicine" if using common chelates such as EDTA. For example, the plant available iron present in a nutrient solution is in the form of Fe EDTA (iron chelate). The Fe molecule(s) are held in a bond with the EDTA chain of the compound. As the larger compound passes the roots, the iron is removed from the chain, and the EDTA is now free, typically picking up "free" element in the nutrient solution and thereby chelating it. This sounds great, but there are some limitations to consider:

1. If the chelating complex is not strong enough, the element can be freed before it reaches the plants' roots, and is therefore unavailable.

2. Some chelates such as EDTA are not effective under a wide range of pH conditions, thereby limiting nutrient uptake and plant performance.

3. An element required for growth can be held too tightly by the chelating complex, and the plant will have to expend more energy to remove the element from the chelate in a sort of "tug-of-war". Sometimes, the element may not be removed at all.

4. Although absorbed by the plant, some elements do not move very quickly throughout the plant, where they are required to satisfy the demands of rapidly growing plants. For example, leaf tip burn in lettuce: calcium is available to the plant, but it cannot be translocated to the actively dividing growing tip quick enough, so the plant exhibits a calcium deficiency, decreasing results for the grower. This is often a problem in warmer growing conditions, such as those found under artificial lighting.

So, what's the best way to make the essential elements required for plant growth available under a range of conditions and highly translocatable (moveable once inside the plant)? High quality fulvic acid.

Fulvic acid is a free radical found in humic matter. It is essentially a fraction of humic acid. However, because you add humic acid to the nutrient solution does not mean that you are adding fulvic acid and receiving the attributed benefits. As a matter of fact, some so-called "fulvic acids" are not fulvic acids at all, although they are being sold as such. The humic acids useful to plants are in the range of 700-70,000 Daltons. A Dalton is the measurement of the size of a molecule in comparison to that of a hydrogen molecule. The smaller the Dalton size, the more biologically active the molecule will be.

True fulvic acids range from 700-7000 Daltons. The quality and effectiveness of a fulvic acid can be measured by comparing which product has the most "smaller" particles within the solution. The potential for overall quality and effectiveness as a "bio-chelate" is greatly determined by the source and type of the material and the method used for extracting and separating the humic acid fractions that are useful to plant growth.

Leonardite and lignite are common sources. Leonardite is a soft, highly oxidized, brown coal-like deposit found in conjunction with deposits of lignite. This is typically a by-product for companies involved with oil exploration. As such, the deposits are not sought after for their qualities with regards to plant performance, but are considered to be "gravy" in the oil exploration process and are sold off relatively inexpensively. However, there are a few deposits in the world that have been sought after strictly for their agronomic (plant favourable) characteristics. General Hydroponics is one company that manufactures products such as Diamond Nectar from these sources, with extraction methods favourable to producing the most bio-active fulvic and humic acid available. By adding high-quality fulvic acid to your nutrient solution, you are in a sense, "magnetizing" the life blood of your plants. Nutrients become more available under a range of growing conditions and can be readily translocated throughout the plant for incredible results. Fulvic acids are typically supplied at the roots with the nutrient solution, but will also greatly increase the effectiveness of foliar sprays. Most flowering, annual plants will benefit most from fulvic acid during the vegetative and early flowering stages. Due to the fact that plants are flowering as a result of environmental stress (eg shortdays) they can stretch in later flowering if fulvic acid is supplied with the nutrients, as the plants are used to "working harder" in this developmental stage. Many growers report that a light foliar spray of fulvic acid the last week before harvest results in tremendous resin/essential oil production on the surface of the leaves. Granular leonardite products such as "Diamond Black" can be incorporated directly into the growing medium. This provides a range of humic acids (including fulvic acids) that will be released slowly throughout the cropping cycle. A study posted on the internet (Canadian Journal of Plant Science) reported a 27% dry matter yield increase in canola (an oil crop) with the addition of 10 grams of high quality, agricultural grade leonardite per 3 kg of soil. These types of results certainly call for some experimentation by indoor gardening enthusiasts. Please feel free to contact Maximum Yield along the way!